Foto personale

Pagina personale di Massimo MESSORI

Dipartimento di Ingegneria "Enzo Ferrari"

Banach T.E.; Fiorini M.; Patel B.R.; Pilati F.; Berti C.; Marianucci E.; Messori M.; Colonna. M.; Toselli M. ( ) - Catalyst composition for the preparation of polyesters [Brevetto (285) - Brevetto]
Abstract

Polyesters are prepd. by the reaction of a dicarboxylic acid, preferably an arom. acid such as terephthalic acid, or an ester or ester-forming deriv. with a dihydroxy compd. such as 1,4-butanediol in the presence of a catalyst compn. comprising the combination of a Ti-based compd. such as tetra-Bu titanate, a Zr-based compd. such as Zr tetrakis(2,4-pentanedionate) and a phosphate-forming compd. such as Na dihydrogen phosphate. This catalyst compn. gives polyesters having relatively low melt viscosities in short reaction times and does not produce an excessive level of undesirable reaction byproducts. Thus, poly(butylene terephthalate) was prepd. from 705 g di-Me terephthalate and 458 g 1,4-butanediol, using tetra-Bu titanate, Zr tetrakis(acetylacetonate), and sodium dihydrogen phosphate at 0.8 mmol Ti and Zr compds./mmol di-Me terephthalate and 245°.

BANACH T E; PILATI F.; COLONNA M.; FIORINI M.; BERTI C.; TOSELLI M.; M. MESSORI; MARIANUCCI E. ( ) - Catalyst composition for the preparation of polyesters, and related processes [Brevetto (285) - Brevetto]
Abstract

The catalyst compn., an improved method of prepn. of a polyester on the two-stage process of ester interchange and polycondensation, comprises the combination of (a) a titanium-based compd. or zirconium-based compd. and (b) a lanthanide series compd. or hafnium, and optionally, a phosphate-forming compd. Thus, poly(butylene terephthalate) was prepd. by a two-stage polymn. of 1,4-butanediol and di-Me terephthalate in an ester interchange reaction process in the presence of 0.08 phr titanium tetrabutoxide and in a polycondensation stage of 0.14 phr hafnium tetrakis(acetylacetonate).

DJ BRUNELLE; C. BERTI; AM CELLI; M. COLONNA; M. FIORINI; E. MARIANUCCI; M. MESSORI; F. PILATI; L. SISTI; P. MARCHESE ( ) - Method for preparing poly(cyclohexane-1,4-dicarboxylate)s from cyclohexane-1,4-dicarboxylic acid, and composition [Brevetto (285) - Brevetto]
Abstract

Poly(1,4-cyclohexanedicarboxylate)s, esp. poly(1,4-cyclohexanedimethylene-1,4-cyclohexanedicarboxylate), are prepd. from at least one relatively non-volatile diol, such as 1,4-cyclohexanedimethanol, and cyclohexane-1,4-dicarboxylic acid by an esterification process in the presence of a catalyst, at a max. temp. of about 260°. In one embodiment the procedure employs a two-step process, the second of which may be performed in the melt or in the solid state. A volatile diol such as ethylene glycol may also be present. Thus, 1,4-cyclohexanedicarboxylic acid-1,4-cyclohexanedimethanol copolymer with Mw 3,500 and mn 1,400 was prepd. in the presence of tetrakis(2-ethylhexyl) titanate.

BANACH T.E.; FIORINI M.; PATEL B.R.; PILATI F.; BERTI C.; MARIANUCCI E.; M. MESSORI; COLONNA M.; TOSELLI M. ( ) - Phosphate-containing catalysts composition for the preparation of polyesters, and related processes [Brevetto (285) - Brevetto]
Abstract

Polyesters having relatively low melt viscosities and without excessive level of undesirable reaction byproducts in short reaction times are prepd. from a dicarboxylic acid/ester/ester-forming deriv. and a dihydroxy compd. in the presence of a catalyst compn. comprising a Ti-based compd., a Zr-based compd. and a phosphate. Thus, poly(butylene terephthalate) was prepd. from 705 g di-Me terephthalate and 458 g 1,4-butanediol, using tetra-Bu titanate, Zr tetrakis(2,4-pentanedionate), and sodium dihydrogen phosphate at 0.8 mmol Ti and Zr compds. per mmol di-Me terephthalate and 245°.

BRUNELLE D.J.; SURIANO J.A.; BERTI C.; CELLI A.M.; COLONNA M.; FIORINI M.; MARIANUCCI E.; MARCHESE P.; M. MESSORI; SISTI L. ( ) - Preparation of hydroxy terminated polyarylates [Brevetto (285) - Brevetto]
Abstract

Patent WO 2005021616, A1, 20050310, WO 2004-US27424, 20040824

D.J. BRUNELLE; A. CELLI; M. FIORINI; C. BERTI; M. COLONNA; P. MARCHESE; E. MARIANUCCI; M. MESSORI; F. PILATI ( ) - Two-step process for preparing poly(cyclohexane-1,4-dicarboxylate)s [Brevetto (285) - Brevetto]
Abstract

Poly(1,4-cyclohexanedicarboxylate)s, esp. poly(1,4-cyclohexanedimethylene-1,4-cyclohexanedicarboxylate), are prepd. from 1 relatively nonvolatile diol, such as 1,4-cyclohexanedimethanol, and cyclohexane-1,4-dicarboxylic acid by an esterification process in the presence of a catalyst, at .ltorsim.260°, which is a 2-step process, the second of which may be performed in the melt or in the solid state. A volatile diol such as ethylene glycol may also be present.

Nanni, A.; Messori, M. ( 2018 ) - A comparative study of different winemaking by-products derived additives on oxidation stability, mechanical and thermal proprieties of polypropylene - POLYMER DEGRADATION AND STABILITY - n. volume 149 - pp. da 9 a 18 ISSN: 0141-3910 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Three different solid wine wastes (peels, seeds and stalks) have been mixed with polypropylene (PP) and tested as stabilizers. Their stabilizing activity has been compared with that of a commercial tannin extract powder, rich in polyphenol. Thermogravimetric analysis, Oxidation Induction Time and Oxidation Onset Temperature measurements have been conducted to investigate the thermo-oxidative stability. Tensile tests, Dynamic Mechanical Analysis and Differential Scanning Calorimetry have been conducted on the samples in order to evaluate the effect of the additives also on the thermal and mechanical properties. Scanning Electron Microscopy have been used to assess the adhesion and distribution of the wine-wastes additives within the PP matrix. Experimental results evidence that all three wine-wastes derived additives do not significantly change the mechanical and thermal properties of PP, meanwhile they enhance its thermal stability. Moreover, the expectation to obtain better results with the commercial tannin extract has not been achieved. The obtained results show how wine wastes can be effectively used as polymer stabilizers and represent a valid alternative because of theirs environmental and cost-effects advantages.

Messori, Massimo; Nobili, Andrea; Signorini, Cesare; Sola, Antonella ( 2018 ) - Mechanical performance of epoxy coated AR-glass fabric Textile Reinforced Mortar: Influence of coating thickness and formulation - COMPOSITES. PART B, ENGINEERING - n. volume 149 - pp. da 135 a 143 ISSN: 1359-8368 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The mechanical performance of epoxy coated AR-glass fabric reinforced composite is investigated. A three-stage manufacturing process is considered, which involves fabric surface functionalization, liquid coating deposition and long-term setting and finally fabric embedment in the mortar matrix. Two epoxy coatings are considered, which only differ by the hardening agent. However, coating thickness is significantly diverse as a result of modified viscosity during liquid deposition. Performance is assessed in uni-axial tension as well as in three-point bending and it is expressed in terms of strength curves, data dispersion, crack pattern and failure mechanism. Remarkably, despite being very similar, the analyzed coatings produce a significantly different performance, especially when data dispersion is incorporated and design limits are considered. Indeed, although both coatings are able to consistently deliver fabric rupture at failure, only the thinnest is associated with small data scattering and an almost plastic post-peak behavior in bending. The associated design elongation limit reaches the maximum allowed value according to the ICC guidelines. In fact, it appears that coating thickness plays a crucial role in determining mechanical performance and fabric flexibility. The proposed manufacturing process proves extremely effective at enhancing matrix-to-fabric adhesion and thereby prevent telescopic failure.

Taormina, Gabriele; Sciancalepore, Corrado; Bondioli, Federica; Messori, Massimo ( 2018 ) - Special Resins for Stereolithography: In Situ Generation of Silver Nanoparticles - POLYMERS - n. volume 10 - pp. da 212 a 225 ISSN: 2073-4360 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The limited availability of materials with special properties represents one of the main limitations to a wider application of polymer-based additive manufacturing technologies. Filled resins are usually not suitable for vat photo-polymerization techniques such as stereolithography (SLA) or digital light processing (DLP) due to a strong increment of viscosity derived from the presence of rigid particles within the reactive suspension. In the present paper, the possibility to in situ generate silver nanoparticles (AgNPs) starting from a homogeneous liquid system containing a well dispersed silver salt, which is subsequently reduced to metallic silver during stereolithographic process, is reported. The simultaneous photo-induced cross-linking of the acrylic resin produces a filled thermoset resin with thermal-mechanical properties significantly enhanced with respect to the unfilled resin, even at very low AgNPs concentrations. With this approach, the use of silver salts having carbon-carbon double bonds, such as silver acrylate and silver methacrylate, allows the formation of a nanocomposite structure in which the release of by-products is minimized due to the active role of all the reactive components in the three dimensional (3D)-printing processes. The synergy, between this nano-technology and the geometrical freedom offered by SLA, could open up a wide spectrum of potential applications for such a material, for example in the field of food packaging and medical and healthcare sectors, considering the well-known antimicrobial effects of silver nanoparticles.

Sciancalepore, C.; Gualtieri, A. F.; Scardi, P.; Flor, A.; Allia, P.; Tiberto, P.; Barrera, G.; Messori, M.; Bondoli, F. ( 2018 ) - Structural characterization and functional correlation of Fe3O4 nanocrystals obtained using 2-ethyl-1,3-hexanediol as innovative reactive solvent in non-hydrolytic sol-gel synthesis - MATERIALS CHEMISTRY AND PHYSICS - n. volume 1 - pp. da 337 a 349 ISSN: 0254-0584 [Articolo in rivista (262) - Articolo su rivista]
Abstract

An original non-hydrolytic sol-gel approach, using 2-ethyl-1,3-hexanediol as reactive solvent, was proposed to synthetize nanostructured magnetite. Iron-oxide nanoparticles were prepared and studied as a function of the precursor-to-solvent ratio. The crystallization degree of nanoparticles was followed by the combined Rietveld and Reference Intensity Ratio method. This procedure has allowed the determination of both amorphous and crystalline content of nanomagnetite, using hematite as suitable internal standard. The results of Rietveld method show that the crystalline content decreases as the precursor-to-solvent is increased, ranging from 67 to 60 wt%. Information on the crystallite size-strain distribution and microstructural evolution of nanocrystals was supplied by line profile analysis of the powder diffraction patterns, employing the Whole Powder Pattern Modeling analysis: the obtained log-normal distribution curves become increasingly narrow and symmetrical, while nanoparticle microstrain increases as the precursor concentration is increased. The dimensional analysis of the Transmission Electron Microscopy images has allowed to obtain the nanoparticle grain-size distribution. Nanoparticle dimensions decreases from 15 to 9 nm increasing the precursor concentration. The comparison between the results of X-ray diffraction and microscopic characterization techniques highlighted the effect of several factors, such as size, shape and microstructure of magnetite nanoparticles, on their functional magnetic response. Magnetic characterizations show that magnetite nanoparticles are not in the superparamagnetic phase even at room temperature, independent of the precursor concentration. On the other hand, the room-temperature saturation magnetization, ranging from 73 to 60 emu/g, is a function of the nanoparticle average size, decreasing as the precursor concentration increases.

Sciancalepore, Corrado; Moroni, Fabrizio; Messori, Massimo; Bondioli, Federica ( 2017 ) - Acrylate-based silver nanocomposite by simultaneous polymerization-reduction approach via 3D stereolithography - COMPOSITES COMMUNICATIONS - n. volume 6 - pp. da 11 a 16 ISSN: 2452-2139 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This study demonstrates the feasibility of printing 3D composite objects based on acrylic photocurable formulations, containing in situ generated silver nanoparticles (AgNPs). In fact, the laser radiation of a commercial stereolithography printer was used to both selectively cure, layer by layer, the acrylic resin and to reduce a silver salt to AgNPs (having dimensions ranging between 10 and 25 nm). The most suitable formulation was developed using silver acetate to obtain 1% by weight of AgNPs in the final 3D structures. The presence of the filler causes an increase in the physical and mechanical properties of the samples that become significantly stiffer and stronger than the pristine matrix. Antibacterial properties and electrical conductivity measurements performed on the printed samples gave promising results for the use of the developed formulation for the building of 3D polymeric structures with improved multifunctional properties.

Marziano, M.; Tonello, S.; Serzanti, M.; Borghetti, M.; Lopomo, N. F.; Serpelloni, M.; Pandini, S.; Merlettini, A.; Gualandi, C.; Focarete, M. L.; Messori, M.; Toselli, M.; Uberti, D.; Memo, M.; Dell’era, P.; Sardini, E. ( 2017 ) - Carbon on poly(epsilon-caprolactone) (PCL) ink-jet printed sensor for monitoring cell cultures of myoblasts ( Joint Conference of the European Medical and Biological Engineering Conference, EMBEC 2017 and Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, NBC 2107 - Tampere, Finland - 2017) ( - IFMBE Proceedings ) (Springer Verlag ) - IFMBE PROCEEDINGS - n. volume 65 - pp. da 783 a 786 ISBN: 9789811051210 ISSN: 1680-0737 [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Nowadays techniques for sensitive non-invasive, real-time monitoring of cell differentiation and maturation are highly demanded. In light of this, the development of electrochemical printed sensors impedance-based could represent a promising tool. In the present work, we developed 2D ink-jet printed sensors for myoblasts adhesion monitoring, using carbon-based ink on a substrate consisting in non-woven electrospun mats made in crosslinked poly(ε-caprolactone) (PCL). First of all, sensors printability was optimized and the biocompatibility tested. In order to determine the possibility to employ the prepared systems as scaffolds for dynamic cellular cultures, the mechanical response of the PCL scaffold was evaluated through the application of cyclic deformation tests. After that, electrical characterization of ink and substrate was performed, followed by electrochemical impedance-based measurements to evaluate myoblasts adhesion. Biocompatibility assessment showed good results for both carbon and PCL. Mechanical tests findings suggested that a training of 50 cycles and a proper value of strain should be applied before the cell seeding, in order to ensure a subsequent controlled strain amplitude. The sensorized scaffold allowed us to correlate cell adhesion with an increase of impedance module, in agreement with biocompatibility testing. Thus, this first preliminary testing suggested that this non-invasive impedance spectroscopy-based measurement system can be used for sensitive monitoring of cells adhesion, in static and moreover, as suggested from mechanical characterization, in dynamic conditions.

Gullo, Maria; Sola, Antonella; Zanichelli, Gabriele; Montorsi, Monia; Messori, Massimo; Giudici, Paolo ( 2017 ) - Increased production of bacterial cellulose as starting point for scaled-up applications - APPLIED MICROBIOLOGY AND BIOTECHNOLOGY - n. volume 101 - pp. da 8115 a 8127 ISSN: 0175-7598 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Bacterial cellulose is composed of an ultrafine nanofiber network and well-ordered structure; therefore, it offers several advantages when used as native polymer or in composite systems. In this study, a pool of 34 acetic acid bacteria strains belonging to Komagataeibacter xylinus were screened for their ability to produce bacterial cellulose. Bacterial cellulose layers of different thickness were observed for all the culture strains. A high-producing strain, which secreted more than 23 g/L of bacterial cellulose on the isolation broth during 10 days of static cultivation, was selected and tested in optimized culture conditions. In static conditions, the increase of cellulose yield and the reduction of by-products such as gluconic acid were observed. Dried bacterial cellulose obtained in the optimized broth was characterized to determine its microstructural, thermal, and mechanical properties. All the findings of this study support the use of bacterial cellulose produced by the selected strain for biomedical and food applications.

Barrera, G.; Sciancalepore, C.; Messori, M.; Allia, P.; Tiberto, P.; Bondioli, F. ( 2017 ) - Magnetite-epoxy nanocomposites obtained by the reactive suspension method: Microstructural, thermo-mechanical and magnetic properties - EUROPEAN POLYMER JOURNAL - n. volume 94 - pp. da 354 a 365 ISSN: 0014-3057 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Magnetite nanoparticles are prepared by non-hydrolytic sol-gel process in the presence of iron(III)-acetylacetonate as precursor and 2-ethyl-1,3-hexanediol as reactive solvent; the nanoparticle size is affected by the precursor-to-solvent ratio. The suspensions, mixed with bisphenol-A diglycidyl ether, are cured in the presence of ytterbium(III) trifluoromethanesulfonate as cationic initiator. The chain-growth polymerization results in a three-dimensional network where the diol, acting at the same time as reactive solvent and suspending medium, is covalently linked to the epoxy network according to the “activated monomer” mechanism. The filler induces stiffening because of hydrodynamic effects and of a better cross-linking ability in the nanocomposite. Magnetite nanoparticles form aggregates whose size and shape depend on concentration. Isothermal magnetization loops and FC/ZFC DC susceptibility curves indicate that all nanocomposites are dominated by interparticle magnetic interactions resulting in a collective response whose details depend on nanoparticle concentration and degree of aggregation.

Pandini, Stefano; Agnelli, Silvia; Merlettini, Andrea; Chiellini, Federica; Gualandi, Chiara; Paderni, Katia; Focarete, Maria Letizia; Messori, Massimo; Toselli, Maurizio ( 2017 ) - Mutifunctional Electrospun Nonwoven Mats with Two-Way Shape Memory Behavior Prepared from Sol-Gel Crosslinked Poly(epsilon-Caprolactone) - MACROMOLECULAR MATERIALS AND ENGINEERING - n. volume 302 - pp. da 1 a 19 ISSN: 1438-7492 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Nonwoven fibrous mats based on semicrystalline networks are prepared starting from poly(ε-caprolactone) and properly combining electrospinning and sol–gel reactions. The mats are obtained as continuous, randomly oriented micrometric fibers with different network densities. The systems are subjected to thermomechanical cycles to investigate their one-way and two-way shape memory behavior. One-way tests aim at exploring the effects of the deformation temperature on the materials response, with particular interest to the less investigated cold-working conditions (i.e., deformation temperature below Tm). The materials display two-way shape memory capabilities (i.e., the ability to change between two distinguished shapes upon heating and cooling under a fixed nonzero stress) and the effect of the applied stress is explored. The shape memory characterization is accompanied by an ex situ SEM analysis, to describe the concurrent microstructural evolution during the macroscopic shape variation, and by the assessment of their biocompatibility, to explore the suitability of the nonwovens for biomedical applications. (Figure presented.).

Khademeh Molavi, Fatemeh; Ghasemi, Ismaeil; Messori, Massimo; Esfandeh, Masoud ( 2017 ) - Nanocomposites based on poly(L-lactide)/poly(epsilon-caprolactone) blends with triple-shape memory behavior: Effect of the incorporation of graphene nanoplatelets (GNps) - COMPOSITES SCIENCE AND TECHNOLOGY - n. volume 151 - pp. da 219 a 227 ISSN: 0266-3538 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In this study, a novel thermally actuated triple-shape memory polymer (triple-SMP) based on poly(L-lactide) (PLA)/poly(ε-caprolactone) (PCL)/graphene nanoplatelets (GNps) nanocomposite was prepared by facile solution mixing method and the design of which was based on two well-separated melting temperatures. In order to improve the dispersion of GNps in the matrix, functionalization reactions were carried out on the GNPs surface. Functionalization was confirmed by various techniques including FTIR, Raman and TGA analysis. TEM micrographs revealed an exfoliated morphology for the functionalized GNps (FGNps) and a homogenous dispersion in the matrix. The crystallinity behaviour of nanocomposites was investigated by DSC and variable temperature XRD (VT-XRD) analysis and an increase in crystallinity was observed. Dynamic mechanical analysis (DMA) showed that the presence of FGNps improves the fixity and recovery ratios because of increase in crystallinity and thermal conductivity. The best shape memory behavior was obtained for PLA50/PCL50/FGNp 1.5 nanocomposite.

Sciancalepore, Corrado; Bondioli, Federica; Messori, Massimo ( 2017 ) - Non-hydrolytic sol–gel synthesis and reactive suspension method: an innovative approach to obtain magnetite–epoxy nanocomposite materials - JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY - n. volume 81 - pp. da 69 a 83 ISSN: 0928-0707 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Innovative magnetite–epoxy nanocomposites were prepared starting from magnetite nanoparticles suspended in alcoholic or amino reactive solvents, synthesized by non-hydrolytic sol–gel process from iron (III) acetylacetonate. The obtained suspensions, also synthesized using microwave heating, were mixed with an epoxy monomer (bisphenol A diglycidyl ether, DGEBA), and the formulations were subsequently cured. The thermally activated ring-opening polymerization produced a three-dimensional network in which the suspending medium was covalently linked to the epoxy network according to the chain or step polymerization mechanisms during the cross-linking reaction. This synthetic strategy allowed to obtain nanocomposites in which the nanoparticles play an active role in the polymeric structure, affecting the structural (mechanical and thermal) and functional (magnetic) properties of the final system. The presence of magnetite nanoparticles in the composite resulted in distinct reinforcing effects, acting as rigid filler and/or as cross-linking point, depending on the different chemical environment at the nanoparticle–polymer interphase.

Spinella, Alberto; Bondioli, Federica; Nasillo, Giorgio; Renda, Vincenzo; Caponetti, Eugenio; Messori, Massimo; Morselli, Davide ( 2017 ) - Organic-inorganic nanocomposites prepared by reactive suspension method: investigation on filler/matrix interactions and their effect on the nanoparticles dispersion - COLLOID AND POLYMER SCIENCE - n. volume 295 - pp. da 695 a 701 ISSN: 0303-402X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Epoxy resin/TiO2 nanocomposites prepared by both reactivesuspension method, based on in situ synthesis, and conventional mechanical mixing are analysed by solid-state nuclear magnetic resonance and transmission electron microscopy in order to have a deeper insight into the nature of interactions at the polymer/particle interface and their effect on the nanoparticles dispersion. Specifically, solid-state nuclear magnetic resonance experiments showed that the nanoparticles, synthesized by reactive suspension method, can efficiently link the matrix by hydrogen bonds forming a hybrid organic-inorganic 3D network. Such evidences strongly supports our previously reported theory, in which the nanoparticles in situ synthesized by reactive suspension method act not only as rigid filler, but also as actual cross-linking points, dramatically improving the mechanical properties of the polymeric matrix. Moreover, as revealed by transmission electron microscopy investigations, the formation of such hydrogen bonds significantly affect also the nanoparticles distribution, thanks to a stabilizing effect on the nanoparticles’ surface that prevents their aggregation and improves their dispersion.

Boumezgane, Oussama; Messori, Massimo ( 2017 ) - Poly(ethylene glycol)-based shape-memory polymers - INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION - n. volume 22 - pp. da 463 a 471 ISSN: 1023-666X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(ethylene glycol) (PEG) blends photo-curable and thermal activated shape-memory polymers (SMPs), with different activation temperature (Tswitch), have been synthesized and characterized. PEG blends with different molecular weights were chain-end functionalized with isocyanate ethyl methacrylate and photo-cured with UV lamp. Degree of cross-linking of the blend network, determined by gel content measurement, resulted as higher than 95%. The thermal and thermomechanical properties of these SMPs PEG blends were characterized by differential scanning calorimetry and dynamic mechanical analysis. The shape-memory properties of the networks were quantified using thermomechanical three-point bending experiments and showed strain fixity rates higher than 99% and a minimum strain recovery ratio of 82%.

Checchi, Marta; Bertacchini, Jessika; Grisendi, Giulia; Smargiassi, Alberto; Sola, Antonella; Messori, Massimo; Palumbo, Carla ( 2017 ) - Proposal of a Novel Natural Biomaterial, the Scleral Ossicle, for the Development of Vascularized Bone Tissue In Vitro - BIOMEDICINES - n. volume 6 - pp. da 3 a 10 ISSN: 2227-9059 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Recovering of significant skeletal defects could be partially abortive due to the perturbations that affect the regenerative process when defects reach a critical size, thus resulting in a non-healed bone. The current standard treatments include allografting, autografting, and other bone implant techniques. However, although they are commonly used in orthopedic surgery, these treatments have some limitations concerning their costs and their side effects such as potential infections or malunions. On this account, the need for suitable constructs to fill the gap in wide fractures is still urgent. As an innovative solution, scleral ossicles (SOs) can be put forward as natural scaffolds for bone repair. SOs are peculiar bony plates forming a ring at the scleral-corneal border of the eyeball of lower vertebrates. In the preliminary phases of the study, these ossicles were structurally and functionally characterized. The morphological characterization was performed by SEM analysis, MicroCT analysis and optical profilometry. Then, UV sterilization was carried out to obtain a clean support, without neither contaminations nor modifications of the bone architecture. Subsequently, the SO biocompatibility was tested in culture with different cell lines, focusing the attention to the differentiation capability of endothelial and osteoblastic cells on the SO surface. The results obtained by the above mentioned analysis strongly suggest that SOs can be used as bio-scaffolds for functionalization processes, useful in regenerative medicine.

Fabbri, Paola; Messori, Massimo ( 2017 ) - Surface Modification of Polymers: Chemical, Physical, and Biological Routes ( - Modification of polymer properties ) - pp. da 109 a 130 ISBN: 9780323443531 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Modification of Polymer Properties provides, for the first time, in one title, the latest information on gradient IPNs and gradient copolymers. The book covers the broad range of polymer modification routes in a fresh, current view representing a timely addition to the technical literature of this important area. Historically, blends, copolymers, or filled polymers have been developed to meet specific properties, or to optimize the cost/properties relationship. Using the gradient structure approach with conventional radical polymerization, it has been shown that it is possible to optimize properties if appropriate gradients in the composition of copolymer chains are obtained. An overview of the gradient structure approach for designing polymers has not appeared in the recent literature and this title covers the different methods used to modify properties, offering the whole range of ways to modify polymers in just one volume and making this an attractive option for a wide audience of practitioners. The approach for each chapter is to explain the fundamental principles of preparation, cover properties modification, describe future research and applications as examples of materials that may be prepared for specific applications, or that are already in use, in present day applications. The book is for readers that have a basic background in polymer science, as well as those interested in the different ways to combine or modify polymer properties.

Tana, Francesca; Messori, Massimo; Contini, Davide; Cigada, Alberto; Valente, Teodoro; Variola, Fabio; De Nardo, Luigi; Bondioli, Federica ( 2017 ) - Synthesis and characterization of scratch-resistant hybrid coatings based on non-hydrolytic sol-gel ZrO2 nanoparticles - PROGRESS IN ORGANIC COATINGS - n. volume 103 - pp. da 60 a 68 ISSN: 0300-9440 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Hybrid transparent coatings based on zirconia nanoparticle fillers and epoxy resin were designed to increase scratch resistance of commodity polymers without impairing their optical properties. Suspensions of nano-crystalline ZrO2 in benzyl alcohol were synthesized via a versatile non-hydrolytic sol-gel process using ZrCl4 as precursor. The obtained ZrO2 nanoparticles showed a crystalline structure attributable to a tetragonal phase and an average particle size of 2 nm. ZrO2 nanoparticles, suspended in tert-butanol, were mixed with a commercial epoxy resin (5 and 10%wt.). The organic solvent was then evaporated and hybrid composites were deposited on polycarbonate and poly(methyl methacrylate). The obtained coatings showed a homogeneous adhesion and a negligible effect on the transparency of these polymers. An increased scratch-resistance was obtained by increasing the ZrO2 nanoparticles content.

Yari, H.; Mohseni, M.; Messori, M. ( 2016 ) - A scratch resistant yet healable automotive clearcoat containing hyperbranched polymer and POSS nanostructures - RSC ADVANCES - n. volume 6 - pp. da 76028 a 76041 ISSN: 2046-2069 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In this paper a typical acrylic melamine clearcoat has been modified with hyperbranched polymer and polyhedral oligomeric silsesquioxane nanostructures to simultaneously enhance its scratch resistance and healing ability. Scratch behaviour and healing performance of clearcoats were investigated by micro-scratching and confocal profilometry techniques. Various techniques were employed to correlate scratch resistance and healing enhancements to the various mechanical and structural characteristics of nano clearcoats. Enhanced scratch resistance was attributed to the increased elastic recovery of the clearcoats in the presence of nano-structured modifiers. In addition, the improved self-healing performance was assigned to the partial replacement of covalent cross-links with physical ones i.e. H-bonding. Simultaneous reinforcement with covalent and physical linkages led to the formation of a more flexible network which maintains its mechanical integrity at ambient temperature and also provides dynamic chain movements for thermal healing treatments at high temperature.

Merlettini, Andrea; Pandini, Stefano; Agnelli, Silvia; Gualandi, Chiara; Paderni, Katia; Messori, Massimo; Toselli, Maurizio; Focarete, Maria Letizia ( 2016 ) - Facile fabrication of shape memory poly(ϵ-caprolactone) non-woven mat by combining electrospinning and sol-gel reaction - RSC ADVANCES - n. volume 6 - pp. da 43964 a 43974 ISSN: 2046-2069 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(ϵ-caprolactone)-based non-woven fibrous mats showing excellent one-way shape memory properties were obtained through a straightforward approach by combining electrospinning process and sol-gel reaction. A solution of partially crosslinked α,ω-triethoxysilane-terminated poly(ϵ-caprolactone) was used to obtain bead-free fibers through electrospinning. Non-woven mats with different crosslinking degrees have been prepared and the effect of the different crosslinking extent and of the microfibrous structure were correlated to the mechanical and shape memory properties of the material. The evolution of fiber architecture within the non-woven mat following deformation and shape memory cycles was also investigated.

Lashgari, Soheila; Karrabi, Mohammad; Ghasemi, Ismaeil; Azizi, Hamed; Messori, Massimo ( 2016 ) - Graphene nanoplatelets dispersion in poly(l-lactic acid): preparation method and its influence on electrical, crystallinity and thermomechanical properties - IRANIAN POLYMER JOURNAL - n. volume 25 - pp. da 193 a 202 ISSN: 1026-1265 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(l-lactic acid) (PLLA)/graphene nanoplatelets (GnP) nanocomposites were prepared through solvent casting and coagulation methods. The better dispersion of graphene was achieved by ultrasounds and its effect on crystallinity, thermomechanical and electrical properties of PLLA were studied and compared in both methods. Differential scanning calorimetry (DSC) was used to investigate the crystallinity of PLLA and its composites. Field emission gun scanning electron microscope (FEG-SEM) and wide-angle X-ray scattering (WAXS) were employed to characterize the microstructure of PLLA crystallites. Dynamic mechanical thermal analysis (DMTA) was performed to study the thermomechanical properties of the nanocomposites. FEG-SEM images illustrated finer dispersion of GnP in samples obtained by coagulation method with respect to solvent casting method. Graphene imparted higher electrical conductivity to nanocomposites obtained by solvent casting under ultrasound due to better formation of graphene network. DSC thermograms and their resulting data showed positive effects of GnP on crystallization kinetics of PLLA in both methods enhanced by the nucleating effect of graphene particles. Meanwhile, the effect of GnP, as nucleating agent, was more prominent in samples produced by coagulation method without utilization of ultrasounds. WAXS patterns represented the same characteristic peaks of PLLA in nanocomposite specimens suggesting similar crystalline structure of PLLA in presence of graphene, and the intensified peaks of nanocomposites compared to neat PLLA confirmed the DSC results regarding its improved crystallinity. Graphene increased storage modulus in rubbery region and glass transition temperature of nanocomposites in the coagulation method due to restricted mobility of PLLA chains.

Sangermano, Marco; Perrot, Alexandre; Gigot, Arnaud; Rivolo, Paola; Pirri, Fabrizio; Messori, Massimo ( 2016 ) - Hydrophobic Scratch Resistant UV-Cured Epoxy Coating - MACROMOLECULAR MATERIALS AND ENGINEERING - n. volume 301 - pp. da 93 a 98 ISSN: 1438-7492 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A selective modification of the surface properties of UV-cured epoxy films was achieved, with an important enhancement of hydrophobicity and scratch resistance, by dispersion on the UV-curable formulations of fluorinated functionalized silica particles. The photopolymeriza- tion process was investigated and the films were fully characterized. Contact angle measurements with water on UV-cured films showed a linear increase of the contact angle of cross-linked films by increasing the functionalized SiO2 content in the photocurable formulation. Also, a consistent and linear improvement of penetration resistance was noted in terms of penetration depth by increasing the fluorinated functionalized silica content.

Lashgari, S.; Karrabi, M; Ghasemi, I.; Azizi, H.; Messori, M.; Paderni, K. ( 2016 ) - Shape memory nanocomposite of poly(L-lactic acid)/graphene nanoplatelets triggered by infrared light and thermal heating - EXPRESS POLYMER LETTERS - n. volume 10 - pp. da 349 a 359 ISSN: 1788-618X [Articolo in rivista (262) - Articolo su rivista]
Abstract

In this study, the effect of graphene nanoplatelets (GNPs) on the shape memory properties of poly(L-lactic acid) (PLLA) was studied. In addition to thermal activation, the possibility of infrared actuating of thermo-responsive shape memory PLLA/GNPs nanocomposite was investigated. The incorporated GNPs were expected to absorb infrared wave’s energy and activate shape memory PLLA/GNPs. Different techniques such as differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), field emission gun scanning electron microscope (FEG-SEM) and dynamic mechanical thermal analysis (DMTA) were used to characterize samples. DSC and WAXD results indicated that GNPs augmented crystallinity due to nucleating effect of graphene particles. GNPs improved both thermal and infrared activating shape memory properties along with faster response. Pure shape memory PLLA was slightly responsive to infrared light and its infrared actuated shape recovery ratio was 86% which increased to more than 95% with loading of GNPs. Drastic improvement in the crystallinity was obtained in nanocomposites with lower GNPs contents (0.5 and 1 wt%) due to finer dispersion of graphene which resulted in more prominent mechanical and shape memory properties enhancement. Infrared activated shape memory PLLA/GNPs nanocomposites can be developed for wireless remote shape control of smart medical and bio-systems.

Yahyaei, Hossein; Mohseni, Mohsen; Ghanbari, Hossein; Messori, Massimo ( 2016 ) - Synthesis and characterization of polyhedral oligomeric titanized silsesquioxane: A new biocompatible cage like molecule for biomedical application - MATERIALS SCIENCE AND ENGINEERING. C, BIOMIMETIC MATERIALS, SENSORS AND SYSTEMS - n. volume 61 - pp. da 293 a 300 ISSN: 0928-4931 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic-inorganic hybrid materials have shown improved properties to be used as biocompatible coating in biomedical applications. Polyhedral oligomeric silsesquioxane (POSS) containing coatings are among hybrid materials showing promising properties for these applications. In this work an open cage POSS has been reacted with a titanium alkoxide to end cap the POSS molecule with titanium atom to obtain a so called polyhedral oligomeric metalized silsesquioxane (POMS). The synthesized POMS was characterized by FTIR, RAMAN and UV-visible spectroscopy as well as 29Si NMR and matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) techniques. Appearance of peaks at 920 cm- 1 in FTIR and 491 cm- 1 and 1083 cm- 1 in Raman spectra confirmed Si-O-Ti linkage formation. It was also demonstrated that POMS was in a monomeric form. To evaluate the biocompatibility of hybrids films, pristine POSS and synthesized POMS were used in synthesis of a polycarbonate urethane polymer. Results revealed that POMS containing hybrid, not only had notable thermal and mechanical stability compared to POSS containing one, as demonstrated by DSC and DMTA analysis, they also showed controlled surface properties in such a manner that hydrophobicity and biocompatibility were both reachable to give rise to improved cell viability in presence of human umbilical vein endothelial cells (HUVEC) and MRC-5 cells.

Pandini, S.; Dioni, D.; Paderni, K.; Messori, M.; Toselli, M.; Bontempi, E.; Ricco, T. ( 2016 ) - The two-way shape memory behaviour of crosslinked poly(e-caprolactone) systems with largely varied network density - JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES - n. volume 27 - pp. da 1388 a 1403 ISSN: 1045-389X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The two-way shape memory behaviour of semicrystalline networks was investigated on systems based on poly(e-caprolactone) featuring significantly different network architecture. Crosslinked poly(e-caprolactone)s were prepared by thermal curing from methacrylic end-capped linear chains having various methacrylation degrees. By conveniently reducing the methacrylation degree, the crosslink density of cured materials was varied over a range of one order of magnitude, leading to comparable changes in the material compliance in the rubbery region, but only to moderate variations in melting and crystallization temperatures (Tm and Tc) and in the crystallinity content. When subjected to constant non-zero stress and to cooling–heating cycles from above Tm to below Tc, the materials undergo a reversible two-way elongation–contraction effect, whose extent depends on material structure and applied stress. The structural changes in the crystalline phase accompanying the cooling-induced elongation were studied through differential scanning calorimetry and X-ray diffraction analyses. The elongation process involves different contributions of entropy- and crystallization-driven processes, whose amounts were investigated as a function of the loading conditions and the molecular architecture. The role of the network density towards a controlled two-way response is evidenced, showing that a proper value of the crosslink density has to be identified to maximize the two-way elongation capabilities.

Sciancalepore, Corrado; Bondioli, Federica; Messori, Massimo; Barrera, Gabriele; Tiberto, Paola; Allia, Paolo ( 2015 ) - Epoxy nanocomposites functionalized with in situ generated magnetite nanocrystals: Microstructure, magnetic properties, interaction among magnetic particles - POLYMER - n. volume 59 - pp. da 278 a 289 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Magnetite nanoparticles in the range 7-10.5 nm were prepared by non hydrolytic sol-gel (NHSG) process in the presence of benzyl alcohol in different concentrations. The suspensions were mixed with bisphenol A diglycidyl ether (DGEBA) and cured in the presence of ytterbium(III) trifluoromethanesulfonate as cationic initiator. Magnetite nanoparticles and epoxy nanocomposites were characterized by structural, chemical and magnetic techniques. A procedure of data analysis is proposed to determine value, sign and surface contribution of the magnetic anisotropy of nanoparticles by comparing the information gained from field-cooled/zero-field-cooled magnetization curves and TEM images. Above blocking temperature, the nanoparticles dispersed in the epoxy resin give rise to an interacting superparamagnetic system and follow the corresponding scaling law. A model explains why the magnetic interaction energy depends not only on nanoparticle concentration in the epoxy but also on concentration fluctuations, being larger in samples where the nanoparticle dispersion is not uniform.

Morselli, Davide; Bondioli, Federica; Sangermano, Marco; Messori, Massimo ( 2015 ) - Epoxy networks reinforced with TiO2 generated by nonhydrolytic sol-gel process: a comparison betweenin situandex situsyntheses to obtain filled polymers - POLYMER ENGINEERING AND SCIENCE - n. volume 55 - pp. da 1689 a 1697 ISSN: 0032-3888 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Titania nanoparticles suspended in benzyl alcohol (BzOH) were generated by nonhydrolytic sol–gel process starting from titanium tetrachloride. The obtained suspensions were mixed with 3,4-epoxycyclohexylmethyl-3,4-epoxycy- clohexanecarboxylate epoxy resin, and the formulations were cured in the presence of ytterbium(III) trifluoromethanesulfonate as cationic initiator. The thermally activated cationic ring-opening polymerization produced a three-dimensional network in which the suspending medium BzOH was covalently linked to the epoxy network according to the “activated monomer” mechanism during the propagation step. The presence of titania nanoparticles resulted in a reinforcing and stiffening effect due to both their hydrodynamic effect and, most important, a significantly higher cross-linking density of the composite material with respect to the unfilled epoxy resin. A comparison with similar composites obtained by physical incorporation of preformed titania particles was also reported in order to compare the in situ and ex situ filler generation for preparing nanocomposites.

Acebo, Cristina; Fernández-Francos, Xavier; Santos, José-Ignacio; Messori, Massimo; Ramis, Xavier; Serra, Àngels ( 2015 ) - Hybrid epoxy networks from ethoxysilyl-modified hyperbranched poly(ethyleneimine) and inorganic reactive precursors - EUROPEAN POLYMER JOURNAL - n. volume 70 - pp. da 18 a 27 ISSN: 0014-3057 [Articolo in rivista (262) - Articolo su rivista]
Abstract

New epoxy–silica hybrid coatings were prepared by a dual process consisting of a sol–gel process using tetraethoxysilane (TEOS) or 3-glycidyloxypropyl trimethoxysilane (GPTMS) in the presence of hyperbranched poly(ethyleneimine) with ethoxysilyl groups at the chain ends (PEI-Si) followed by a homopolymerization of diglycidylether of bisphenol A (DGEBA) using 1-methylimidazole (1-MI) as anionic initiator. The influence of the amount of TEOS and GPTMS in the characteristics of the coating was examined. Thin transparent films were obtained and their morphology was observed by transmission electron microscopy (TEM). The hydrolytic condensation was confirmed by 29Si NMR studies. Cage-like nanometric structures were formed in case of adding GPTMS and bigger silica particles on adding TEOS to the formulation. Thermal stability was evaluated by thermo- gravimetry and the scratch resistance properties were also investigated, showing an improvement in resistance to break and to detachment in all the coatings containing GPTMS.

Mokhothu, T.H.; Luyt, A.S.; Morselli, D.; Bondioli, F.; Messori, M. ( 2015 ) - Influence of in situ-generated silica nanoparticles on EPDM morphology, thermal, thermomechanical, and mechanical properties - POLYMER COMPOSITES - n. volume 36 - pp. da 825 a 833 ISSN: 0272-8397 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Silica nanoparticles were synthesized by means of a sol–gel method and generated in ethylene propylene diene monomer rubber (EPDM) by in situ synthesis. The properties were determined using scanning elec- tron microscopy, attenuated total reflectance Fourier- transform infrared spectroscopy, thermogravimetric analysis, tensile testing, dynamic mechanical analysis, swelling tests, and gel content determination. The silica particles were homogenously dispersed in the EPDM matrix, with the presence of agglomerates, especially for high silica contents. The swelling experi- ments showed a decrease in the crosslinking density of the vulcanized rubber due to the presence of the silica nanoparticles. The mechanical properties, how- ever, were significantly improved by the presence of the stiff silica nanoparticles. The effect of the amount of silica on the thermomechanical properties and ther- mal degradation of EPDM was also investigated. The presence of silica showed an increase in the storage and loss moduli at high temperatures, probably due to the increasing filler content. The thermal degradation analysis showed that the presence of silica particles incorporated in the EPDM matrix had no significant influence on the thermal stability of the composites.

Yari, H.; Mohseni, M.; Messori, M. ( 2015 ) - Toughened acrylic/melamine thermosetting clear coats using POSS molecules: Mechanical and morphological studies - POLYMER - n. volume 63 - pp. da 19 a 29 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work attempts to introduce polyhedral oligomeric silsesquioxane compounds as a novel toughening agent for thermosetting systems. For this purpose, an acrylic/melamine thermosetting system was modified by OH-functional silsesquioxane nano-cage. Mechanical and thermo-mechanical behavior of resultant nanocomposites were studied by tensile and DMTA techniques. It was found that low content of silsesquioxane building blocks is sufficient to shift the mechanical behavior of the matrix from a brittle character to a flexible tough one. Various morphological techniques (SEM and TEM equipped with elemental analyzer together with XRD) were also utilized to clarify how nano-cages have been oriented within the matrix. It was revealed that nano-cages have been well dispersed in a molecular scale within the thermosetting network. The good dispersion of silsesquioxane compounds was assigned to the high compatibility within the matrix owing to their compact structure and OH-functional groups available on the cage.

Sangermano, M.; Roppolo, I.; Messori, M. ( 2015 ) - UV-Cured Functional Coatings ( - Photocured Materials ) (Royal Society of Chemistry GBR ) - n. volume 2015 - pp. da 121 a 133 ISBN: 9781782620013 ISSN: 2046-0066 [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

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M. Sangermano; I. Roppolo; M. Messori ( 2014 ) - CHAPTER 7. UV-Cured Functional Coatings ( - RSC Smart Materials - Photocured Materials ) (Royal Society of Chemistry Cambridge GBR ) - pp. da 121 a 133 ISBN: 9781782620013 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

UV-cured functional coatings review

Messori M.; Paderni K.; M. Toselli; S. Pandini ( 2014 ) - Compositi a memoria di forma a base di poli(ε-caprolattone) ( XXI Convegno Nazionale dell’Associazione Italiana di Scienza e Tecnologia delle Macromolecole - Torino - 14-19/09/2014) ( - XXI Convegno Nazionale dell'Associazione Italiana di Scienze e Tecnologie delle Macromolecole ) (Edizioni Nuova Cultura Roma ITA ) - pp. da 199 a 203 ISBN: 9788868123697 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

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Paderni, Katia; Morselli, Davide; Bondioli, Federica; Luyt, Adriaan S.; Mokhothu, Thabang H.; Messori, Massimo ( 2014 ) - EPDM rubber reinforced with titania generated by nonhydrolytic sol-gel process - POLYMER ENGINEERING AND SCIENCE - n. volume 54 - pp. da 2544 a 2552 ISSN: 0032-3888 [Articolo in rivista (262) - Articolo su rivista]
Abstract

EPDM rubber was reinforced with titania in situ generated by using a nonhydrolytic sol-gel (NHSG) process starting from TiCl4 as titania precursor and tert-butanol as oxygen donor. Titania particles in anatase form and with average diameter of 6 nm were synthesized via NHSG route and then the same procedure was adopted in presence of EPDM rubber to obtain composites containing up to 30 wt% of filler. Extraction and equilibrium swelling tests suggested an interfering effect of the NHSG reaction on the vulcanization process of the rubber resulting to a crosslink density which decreased in the presence of titania. Quasistatic and dynamic-mechanical characterizations indicated that the presence of titania as rigid filler in both the unvulcanized and vulcanized EPDM matrix led to a significant increase in stiffness and stress at break. The experimental values of modulus were systematically higher than the values predicted by classical equations suggesting an additional stiffening contribution deriving from the molecular interaction between the rubber and the filler.

Davide Morselli; Federica Bondioli; Marco Sangermano; Ignazio Roppolo; Massimo Messori ( 2014 ) - Epoxy resins reinforced with TiO2 generated by non-hydrolytic sol-gel process - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 131 - pp. da 40470 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Innovative epoxy-titania nanocomposites were prepared starting from titania nanoparticles suspended in benzyl alcohol (BzOH) generated by nonhydrolytic sol–gel process from TiCl4. The obtained suspensions were mixed with an epoxy resin (bisphenol A diglycidyl ether, DGEBA) and the formulations were cured in the presence of ytterbium(III) trifluoromethanesulfonate as cationic initiator. The thermally activated cationic ring-opening polymerization produced a three-dimensional network in which the suspend- ing medium BzOH was covalently linked to the epoxy network according to the “activated monomer” mechanism during the propa- gation step. The presence of titania nanoparticles resulted in a reinforcing and stiffening effect due to both their hydrodynamic effect and, most important, a significantly higher cross-linking density of the composite material with respect to the unfilled epoxy resin.

Pandini, Stefano; Borboni, Alberto; Bodini, Ileana; Vetturi, David; Cambiaghi, Danilo; Paderni, Katia; Messori, Massimo; Toselli, Maurizio; Riccò, Theonis ( 2014 ) - Evaluation of the shape memory performances of poly(ε-caprolactone)- based tubular devices for potential biomedical applications ( 7th International Conference on Times of Polymers (TOP) and Composites 2014 - Ischia, Italy - 22–26 June 2014) ( - AIP CONFERENCE PROCEEDINGS ) - AIP CONFERENCE PROCEEDINGS - n. volume 1599 - pp. da 306 a 309 ISSN: 0094-243X [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

The shape memory behavior of tubular specimens based on crosslinked poly(epsilon-caprolactone) was investigated in order to evaluate their ability i) to restore their shape after being folded in a more compact one, and ii) to exert stress under external confinement (recovery stress). The specimens were prepared following different crosslinking methodologies and with different network densities, in order to tailor the material response in terms of transformation temperatures and recovery stress capabilities. The devices are able to fully recover their shape once heated close to the melting temperature and to exert moderate stresses, that may be controlled through thickness and crosslink density, and whose values were employed to develop a new testing apparatus for the measurement of radial dilation capabilities.

Borsacchi, Silvia; Paderni, Katia; Messori, Massimo; Toselli, Maurizio; Pilati, Francesco; Geppi, Marco ( 2014 ) - Insights into shape-memory poly(ε-caprolactone) materials by solid-state NMR - MACROMOLECULES - n. volume 47 - pp. da 3544 a 3552 ISSN: 0024-9297 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Polymeric materials showing shape-memory behavior are attracting large interest especially in the field of biomaterials. Despite the large number of studies aimed at charaterizing macroscopic features, detailed investigations of properties at the nanometric scale and molecular level are still very few. In this work we present a multinuclear and multitechnique solid-state NMR investigation on recently developed hybrid materials formed by sol-gel cross-linked alkoxysilane terminated poly(e-caprolactone), showing very interesting shape-memory behavior. By investigating several spectral and relaxation properties of Si-29, C-13, and H-1 nuclei present in the hybrid material, we could characterize and compare the structural, dynamic, and phase properties of a sample fixed in a stretched temporary shape with those of a sample in the permanent shape. Interesting differences could be observed: in particular, the sample fixed in the temporary shape showed a larger amount (40% instead of 35%) of crystalline phase and amorphous domains in which polymeric chains experienced a more restricted molecular mobility, as inferred from proton T-2 values. Moreover, from C-13 spectra recorded by varying the orientation of the sample with respect to the direction of the magnetic field, it was possible to clearly detect that about 90% of PCL chains, mainly in the crystalline domains, but also in the amorphous ones, were strongly aligned along the stretching direction. If subjected to heating, so to remove the temporary shape, the sample showed a melting temperature a few degrees higher, a sligthly more rigid melt phase, and a complete loss of molecular alignment.

Galizia, Michele; De Angelis, Maria Grazia; Messori, Massimo; Sarti, Giulio C. ( 2014 ) - Mass transport in hybrid PTMSP/silica membranes - INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - n. volume 53 - pp. da 9243 a 9255 ISSN: 0888-5885 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Hybrid silica/poly(trimethylsilylpropyne) (PTMSP) membranes in which the silica particles are generated in the polymer solution with a sol gel reaction from a tetraethoxysilane (TEOS) precursor were fabricated. The membranes are characterized with microscopic, thermogravimetric, and pycnometric analysis; their sorption and diffusion properties with respect to n-C-4 and n-C-5 vapors are also measured at 25 degrees C. A significant reduction of the polymer specific volume, organic vapor solubility, and diffusivity is observed after incorporation of silica, according to a combination of free volume filling and compressive constraints. The behavior of the hybrid membranes (HM) is opposite that of mixed matrix membranes (MMM) obtained by physical mixing of preformed silica nanoparticles into PTMSP solutions, which show, on the contrary, free volume, vapor solubility, and diffusivity values higher than pure PTMSP. The hybrid membranes are characterized by larger silica domains than mixed matrix ones. Remarkably, however, the transport behavior of both types of membranes can be interpreted, by the same theoretical background, on the basis of a single structural parameter, namely the density of the polymer phase. This parameter allows a direct estimation of the variation of free volume and vapor solubility and diffusivity in both types of membranes, through a NELF/free volume approach.

Messori M.; Fabbri P.; Fabbri E. ( 2014 ) - Melt blending of natural rubber and PBDMS [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Luca Valentini; Paola Fabbri; Massimo Messori; Micaela Degli Esposti; Silvia Bittolo Bon ( 2014 ) - Multilayer films composed of conductive poly(3-hydroxybutyrate)/carbon nanotubes bionanocomposites and a photoresponsive conducting polymer - JOURNAL OF POLYMER SCIENCE. PART B, POLYMER PHYSICS - n. volume 52 - pp. da 596 a 602 ISSN: 0887-6266 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In order to develop new electronic devices, it is necessary to find innovative solutions to the eco-sustainability problem of materials as substrates for circuits. We realized a photoresponsive device consisting of a semiconducting polymer film deposited onto optically semitransparent and conductive biodegradable poly(3-hydroxybutyrate) (PHB)/carbon nanotube (CNT) substrates. The experiments indicated that the PHB-CNT bionanocomposite substrate behaves as an optical window trapping electric charges produced by the photoexcitation of the semiconducting polymer. Such PHB-CNT functional substrates are expected to be attractive for eco-friendly electronics.

Cristina Acebo; Xavier Fernández-Francos; Massimo Messori; Xavier Ramis; Àngels Serra ( 2014 ) - Novel epoxy-silica hybrid coatings by using ethoxysilyl-modified hyperbranched poly(ethyleneimine) with improved scratch resistance - POLYMER - n. volume 55 - pp. da 5028 a 5035 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new hyperbranched poly(ethyleneimine) with ethoxysilyl groups at the chain ends has been synthesized and characterized and then used in epoxy formulations to generate new organic/inorganic hybrid materials. Formulations of different proportions of diglycidylether of bisphenol A and the prepared ethoxysilylated hyperbranched poly(ethyleneimine) were maintained in a thermostatized controlled humidity chamber to form the inorganic silica network by a sol-gel process and then the epoxy resin was cured at higher temperature using 1-methylimidazole as anionic initiator. Transparent hybrid materials were prepared and characterized by thermal tests and their fine morphology was observed by transmission electron microscopy. The formation of the silicon structure was confirmed by 29Si NMR studies. Thermal stability was evaluated by thermogravimetry. Improvement of the mechanical coating performance was confirmed by scratch measurement.

T. H. Mokhothu; A. S. Luyt; M. Messori ( 2014 ) - Preparation and characterization of EPDM/silica composites prepared through non-hydrolytic sol-gel method in the absence and presence of a coupling agent - EXPRESS POLYMER LETTERS - n. volume 8 - pp. da 809 a 822 ISSN: 1788-618X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Ethylene propylene diene monomer (EPDM) rubber composites containing in situ generated silica particles was prepared through a non-hydrolytic sol-gel (NHSG) method with silicon tetrachloride as precursor. The silica particles were homogenously dispersed in the EPDM matrix, but there were agglomerates at high silica contents. The swelling experi- ments showed a decrease in the crosslinking density of the vulcanized rubber due to the presence of the silica particles for both the composites prepared in the presence and absence of a coupling agent, bis-[-3-(triethoxysilyl)-propyl]-tetrasulfide (TESPT). Unlike the composites prepared through a hydrolytic sol-gel (HSG) method with TEOS as precursor, the TESPT did not seem to take part in the sol-gel reaction. The presence of TESPT influenced the interaction and dispersion of the sil- ica particles in the EPDM matrix, which gave rise to increased thermal stability of the EPDM when compared to the com- posites prepared in the absence of TESPT. However, ethylene chloride and TESPT evaporated from the samples at temperatures below the EPDM decomposition range. The values of the Nielsen model parameters, that gave rise to a good agreement with the experimentally determined Young’s modulus values, indicated improved dispersion and reduced size of the silica aggregates in the EPDM matrix. There was also good agreement between the storage modulus and Young’s mod- ulus values. The filler effectiveness (Factor C) indicated a mechanical stiffening effect and a thermal stability contribution by the filler, while the damping reduction (DR) values confirmed that the EPDM interacted strongly with the well dispersed silica particles and the polymer chain mobility was restricted. The tensile properties, however, were in some cases worse than those for the samples prepared through the HSG method in the presence of TEOS.

Taurino, Rosa; Fabbri, Elena; Pospiech, Doris; Synytska, Alla; Messori, Massimo ( 2014 ) - Preparation of scratch resistant superhydrophobic hybrid coatings by sol-gel process - PROGRESS IN ORGANIC COATINGS - n. volume 77 - pp. da 1635 a 1641 ISSN: 0300-9440 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic-inorganic hybrid coatings on glass substrates with superhydrophobic properties and with improved scratch resistance were obtained by means of applying a multilayer approach including multiple sol-gel processes. The coatings exhibited a water contact angle (WCA) higher than 150 degrees. Ultraviolet (UV)-curable vinyl ester resins and vinyltriethoxysilane (VTEOS) as coupling agent were employed to increase the adhesion between substrate and the inorganic layers. The surfaces were characterized by means of dynamic contact angle and roughness measurements. Indeed, the occurrence of superhydrophobic behavior was observed. The scratch resistance of the hybrid coatings was tested to evaluate the adhesion of the coatings to the glass substrate. The proposed preparation method for scratch resistant, mechanically stable, superhydrophobic coatings is simple and can be applied on large areas of different kinds of substrates.

F. Bisi; M. Messori; F. Pilati; M. Toselli ( 2014 ) - Preparazione e caratterizzazione di idrogeli nanocompositi a base di poli(acrilonitrile-co-acrilammide) contenenti grafene ossido ( XXI Convegno Nazionale dell’Associazione Italiana di Scienza e Tecnologia delle Macromolecole - Torino - 14-19/09/2014) ( - XXI Convegno Nazionale dell'Associazione Italiana di Scienze e Tecnologie delle Macromolecole ) (Edizioni Nuova Cultura Roma ITA ) - pp. da 311 a 314 ISBN: 9788868123697 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

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T.H. Mokhothu; A.S. Luyt; M. Messori ( 2014 ) - Reinforcement of EPDM rubber with in situ generated silica particles in the presence of a coupling agent via a sol–gel route - POLYMER TESTING - n. volume 33 - pp. da 97 a 106 ISSN: 0142-9418 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Ethylene propylene diene monomer rubber (EPDM)-silica (SiO2) composites were pre- pared by means of an in situ sol–gel process with tetraethoxysilane (TEOS) as precursor and bis-[-3-(triethoxysilyl)-propyl]-tetrasulfide (TESPT) as coupling agent. Homogenous dispersion of the silica particles was observed in all cases, as well as good adhesion be- tween the filler and the matrix. The swelling and gel content results indicated that the number of crosslinks decreased, while the network was still extensive enough to maintain the high gel content. These results indicate that the coupling agent acted as a bridge be- tween the hydrophilic silica and the hydrophobic rubber and enhanced the rubber-silica interactions. This enhanced interaction gave rise to increased thermal stability of the EPDM. The values of the Nielsen model parameters, which gave rise to good agreement with the experimentally determined Young’s modulus values, indicate improved dispersion and reduced size of silica aggregates in the EPDM matrix. Good agreement was found between the storage modulus and Young’s modulus values. The filler effectiveness (Factor C) indicated a mechanical stiffening effect and a thermal stability contribution by the filler, while the damping reduction (DRNorm) values confirmed that the EPDM interacted strongly with the well dispersed silica particles, and the polymer chain mobility was restricted.

M. Messori; D. Morselli; F. Bondioli; M. Sangermano ( 2014 ) - Resine epossidiche rinforzate con titania generata con processo sol-gel non idrolitico: un confronto fra generazione in situ ed ex situ ( XXI Convegno Nazionale dell’Associazione Italiana di Scienza e Tecnologia delle Macromolecole - Torino - 14-19/09/2014) ( - XXI Convegno Nazionale dell'Associazione Italiana di Scienze e Tecnologie delle Macromolecole ) (Edizioni Nuova Cultura Roma ITA ) - pp. da 353 a 355 ISBN: 9788868123697 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

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Katia Paderni; Paola Fabbri; Maurizio Toselli; Massimo Messori ( 2014 ) - Shape Memory Properties of PBS-Silica Hybrids - MATERIALS - n. volume 7 - pp. da 751 a 768 ISSN: 1996-1944 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A series of novel Si–O–Si crosslinked organic/inorganic hybrid semi-crystalline polymers with shape memory properties was prepared from alkoxysilane-terminated poly(butylene succinate) (PBS) by water-induced silane crosslinking under organic solvent-free and catalyst-free conditions. The hydrolyzation and condensation of alkoxysilane end groups allowed for the generation of silica-like crosslinking points between the polymeric chains, acting not only as chemical net-points, but also as inorganic filler for a reinforcement effect. The resulting networks were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic-mechanical analysis (DMA) and tensile and shape memory tests to gain insight into the relationship between the polymeric structure, the morphology and the properties. By controlling the molecular weight of the PBS precursor, a fine tuning of the crosslinking density and the inorganic content of the resulting network was possible, leading to different thermal, mechanical and shape memory properties. Thanks to their suitable morphology consisting of crystalline domains, which represent the molecular switches between the temporary and permanent shapes, and chemical net-points, which permit the shape recovery, the synthesized materials showed good shape memory characteristics, being able to fix a significant portion of the applied strain in a temporary shape and to restore their original shape above their melting temperature.

Massimo Messori; Elena Fabbri ( 2014 ) - Studio di membrane realizzate con elastomeri termoplastici [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Pandini, Stefano; Riccò, Theonis; Borboni, Alberto; Bodini, Ileana; Vetturi, David; Cambiaghi, Danilo; Toselli, Maurizio; Paderni, Katia; Messori, Massimo; Pilati, Francesco; Chiellini, Federica; Bartoli, Cristina ( 2014 ) - Tailored one-way and two-way shape memory capabilities of poly(ε-Caprolactone)-based systems for biomedical applications - JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE - n. volume 23 - pp. da 2545 a 2552 ISSN: 1059-9495 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This paper investigates the shape memory capabilities of semicrystalline networks, focusing the attention on poly(epsilon-caprolactone) (PCL) systems, a class of materials that allows to satisfy important requirements for their applications as biomedical devices, such as the good biocompatibility, the fast recovery of large "temporary" shape configurations, and the easy tailoring of the transformation temperatures. The materials were prepared with various crosslink densities and crosslinking methodologies; in particular, beside a thermal crosslinking based on reactive methacrylic end groups, a novel type of covalently crosslinked semicrystalline systems was prepared by a sol-gel approach from alkoxysilane-terminated PCL precursors, so as to avoid potentially toxic additives typically used for free-radical thermal curing. The materials were subjected to biological tests, to study their ability in sustaining cell adhesion and proliferation, and to thermal characterizations, to evaluate the possibility to tailor their melting and crystallization temperatures. The one-way shape memory (i.e., the possibility to set the material in a given configuration and to recover its pristine shape) and the two-way shape memory response (i.e., the triggered change between two distinguished shapes on the application of an on-off stimulus) were studied by applying optimized thermo-mechanical cyclic histories. The ability to fix the applied shape and to recover the original one on the application of heating (i.e., the one-way effect) was evaluated on tensile bars; further, to investigate a potential application as self-expandable stents, isothermal shape memory experiments were carried out also on tubular specimens, previously folded in a temporary compact configuration. The two-way response was studied through the application of a constant load and of a heating/cooling cycle from above melting to below the crystallization temperature, leading to a reversible elongation/contraction effect, involving maximum strain changes up to about 80%, whose extent may be controlled through the crosslink density.

Pandini, Stefano; Dioni, Daniele; Paderni, Katia; Messori, Massimo; Toselli, Maurizio; Riccò, Theonis ( 2014 ) - The network density as tailoring parameter for the two-way shape memory response of crosslinked poly(ε-caprolactone) ( 7th International Conference on Times of Polymers (TOP) and Composites 2014 - Ischia, Italy - 22–26 June 2014) ( - AIP CONFERENCE PROCEEDINGS ) - n. volume 1599 - pp. da 270 a 273 ISSN: 0094-243X [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

The "two-way" shape memory response of semicrystalline networks was studied on poly(epsilon-caprolactone)-based systems, crosslinked by thermal curing of methacrylic end-capped linear chains. By changing the methacrylation degree of the precursors, it was possible to vary the network density over one order of magnitude, without any remarkable change in their transition temperatures and crystallinity content. When subjected to a constant stress and to a cooling-heating cycle from above T-m to below T-c, the materials display reversible two-way shape memory capabilities, consisting in a cyclic elongation-contraction effect, which involves significant variations of strain. Two different cooling induced elongational processes are evidenced, one due to entropy elasticity and the other to a crystallization driven effect. The amount of elongation that may be achieved depends on the network density and on the applied stress, and it is maximized for systems with a crosslink density that allows to exploit both the entropy-and the crystallization-induced effect.

Nicotra, Marco; Moncalero, Matteo; Messori, Massimo; Fabbri, Elena; Fiorini, Maurizio; Colonna, Martino ( 2014 ) - Thermo-mechanical and impact properties of polymeric foams used for snow sports protective equipment - PROCEDIA ENGINEERING - n. volume 72 - pp. da 678 a 683 ISSN: 1877-7058 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The thermo-mechanical and impact properties of materials used for hard-shell and soft-shell back protectors have been analysed in order to understand the mechanism of action of the foams used for protective equipment. Dynamical mechanical analysis has shown that materials used for soft-shell protectors present frequency-sensitive properties that permit to have a soft response when stressed at low speed and a hard response when subjected to a high-speed impact. Furthermore, by means of drop weight impact tests, the shock absorbing characteristics of the materials have been investigated at two temperatures pointing out the differences between soft and hard-shell protectors; in addition it has been demonstrated that the materials used for soft-shell protectors maintain their protective properties after multi-impacts on the same point.

Yari, H.; Mohseni, M.; Messori, M.; Ranjbar, Z. ( 2014 ) - Tribological properties and scratch healing of a typical automotive nano clearcoat modified by a polyhedral oligomeric silsesquioxane compound - EUROPEAN POLYMER JOURNAL - n. volume 60 - pp. da 79 a 91 ISSN: 0014-3057 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The present work has studied the influence of an OH-functionalized polyhedral oligomeric silsesquioxane(POSS) nano-structure on the scratch resistance of a typical acrylic melamine clearcoat. Scratch resistance and the healing ability of clearcoats were investigated by micro-scratch studies and confocal profilometry techniques. In addition, hardness and thermo-mechanical characteristics of clearcoats were investigated by micro-indentation and dynamic mechanical thermal analysis (DMTA) respectively, to correlate the scratch behavior to the mechanical and structural properties of the clearcoats. The results revealed that incorporation of FOSS cages into clearcoats could effectively enhance the scratch resistance. This was attributed to the higher hardness and cross-linking density of the resulting nanocomposite coatings. The healing results also demonstrated that nanocomposites had a higher healing ability compared to the neat clearcoat. The higher healing of nanocomposites was explained by the physical H-bonding interactions formed in vicinity of POSS cages. The transparency measurements proved that these improvements were fulfilled without any negative effect on the optical quality of clearcoats.

M. Messori; M. Degli Esposti; K. Paderni; S. Pandini; S. Passera; T. Riccò; M. Toselli ( 2013 ) - Chemical and thermomechanical tailoring of the shape memory effect in poly(epsilon-caprolactone)-based systems - JOURNAL OF MATERIALS SCIENCE - n. volume 48 - pp. da 424 a 440 ISSN: 0022-2461 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The thermally activated shape memory response of polymeric materials results from a combination of the material molecular architecture with the thermal/deformational history, or ‘programming’. In this work, we investigate the shape memory response of systems based on poly (epsilon-caprolactone) (PCL) so as to explore the adoption of proper chemical and thermomechanical tailoring routes. Cross-linked semicrystalline PCL-based materials are prepared by different molecular architectures starting from linear, three- and four-arms star PCL functionalized with methacrylate end groups, allowing to tune the melting temperature, Tm, ranging between 36 and 55 °C. The materials’ ability to display the shape memory is investigated by the application of proper thermomechanical cycles on specimens deformed at two different temperatures (23 and 65 °C, i.e. below and above the Tm, respectively). The shape memory response is studied under dynamic thermal conditions in thermally activated recovery tests, to identify the typical transformation temperatures, and under isothermal conditions at given recovery temperatures, to monitor shape recovery as a function of time. All the specimens are capable of full recovery on specific thermal ranges influenced by both melting and deformation temperatures. Specimens deformed above Tm are able to recover the whole deformation in a very narrow temperature region close to Tm, while those deformed at room temperature display broader recovery processes, those onset at about 30 °C. Isothermal tests reveal that when the deformed material is subjected to a constant recovery temperature, the amount of recovered strain and the time required strongly depend on the particular combination of melting temperature, deformation temperature and recovery temperature.

M. Messori ( 2013 ) - Confronto fra materiali plastici per applicazioni nell'imballaggio (proprietà̀ barriera e resistenza chimica) [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Il progetto riguarda una ricerca bibliografica mirata al confronto di diversi materiali plastici utilizzabili nel settore imballaggio. In particolare verranno ricercate proprietà barriera (permeabilità a gas e a vapori), proprietà di resistenza chimica e ogni altra proprietà utile per un esaustivo confronto fra i materiali.

Sangermano, Marco; Naguib, Mohamed; Messori, Massimo ( 2013 ) - Fracture toughness enhancement of UV-cured epoxy coatings containing Al2O3 nanoparticles - MACROMOLECULAR MATERIALS AND ENGINEERING - n. volume 298 - pp. da 1184 a 1189 ISSN: 1438-7492 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Commercially available alumina powder (-Al2O3 nanoparticles with 150nm diameter) is added up to 4 vol% into cycloaliphatic epoxy resins and cured using UV light. Chemical and physical investigations of these UV-cured, reinforced epoxy resin are carried out. The FTIR analysis indicates decreasing effect of these nanoparticles on the curing rate. The FESEM study for the fracture surface of reinforced epoxy resins revealed increase in the surface roughness that might be a sign of toughness enhancement. Also, an improvement in the scratch resistance was noticed for samples containing alumina filler.

P. Fabbri; M. Messori ( 2013 ) - Melt blending of thermoplastic polyurethanes (TPU) and PBDMS [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Marco Sangermano; David Foix; Galder Kortaberria; Massimo Messori ( 2013 ) - Multifunctional antistatic and scratch resistant UV-cured acrylic coatings - PROGRESS IN ORGANIC COATINGS - n. volume 76 - pp. da 1191 a 1196 ISSN: 0300-9440 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic–inorganic antistatic hybrid acrylic coatings were prepared. Trialkoxy-silyl ammonium salt was added to the photocurable formulations in order to introduce an antistatic additive which could be covalently linked to the hybrid network through a co-condensation reaction involving the alkoxy groups. The influence of the antistatic additive on the radical photopolymerization reaction of the acrylic resin was evaluated by real time FTIR, keeping the inorganic precursor content constant at 20 phr and increasing the trialkoxy-silyl ammonium salt in the range between 5 and 15 phr. When the samples were cured under nitrogen atmosphere, a complete conversion of acrylic double bonds was achieved after 90 s of irradiation both for the acrylic resin and the formulations containing the ammonium salt. The scratch behavior of coatings was investigated by carrying out of progressive load scratch test. The penetration depth (Pd) and the residual depth patterns were investigated for all the hybrid films. A consistent improvement of penetration resistance by increasing alkoxy-ammonium salt content was noted in terms of Pd. Inorganic component and antistatic additives increase ε′ and σAC values of the hybrid coatings and decrease the resistivity ones, showing their efficiency for increasing antistatic properties of coatings, improved with respect to the pure acrylic resin.

H. Yari; M. Mohseni; Z. Ranjbar; M. Messori; M.R. Naimi-Jamal ( 2013 ) - Novel toughened automotive clearcoats modified by a polyester-amide hyperbranched polymer: structural and mechanical aspects - POLYMERS FOR ADVANCED TECHNOLOGIES - n. volume 24 - pp. da 495 a 502 ISSN: 1042-7147 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The present work attempts to study the mechanical properties and toughness behavior of a typical acrylic melamine clearcoat modified by a polyester-amide hyperbranched polymer (HBP). Formulations were such that 0, 5, 10, 25 and 50% (molar percent) of total acrylic hydroxyl groups were stoichiometrically substituted by those of HBP. Bulk and surface of the clearcoats were studied by various mechanical techniques including hardness, tensile, dynamic mechanical thermal analysis (DMTA), nano-indentation and scratch tests. In addition a scanning electron microscope (SEM) was utilized to observe the morphology of the fractured films. The bulk mechanical properties showed that a low loading (5 molar %) of HBP was sufficient to considerably increase the bulk hardness, cross-linking density and toughness. DMTA and SEM results proved the occurrence of a single-phase blend and that the shear deformation was the main toughening mechanism of HBP modified clearcoats. In general, it was revealed that the HBP not only could act as an excellent compatible toughening agent, but also maintained the clarity of the clearcoat and increased its scratch resistance.

S. Pandini; F. Baldi; K. Paderni; M. Messori; M. Toselli; F. Pilati; A. Gianoncelli; M. Brisotto; E. Bontempi; T. Riccò ( 2013 ) - One-way and two-way shape memory behaviour of semi-crystalline networks based on sol-gel cross-linked poly(ε-caprolactone) - POLYMER - n. volume 54 - pp. da 4253 a 4265 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In this work we have explored the shape memory capabilities of a novel type of covalently cross-linked semi-crystalline polymers, prepared by exploiting the mild solegel chemistry, starting from alkoxysilane-terminated poly(ε-caprolactone) (PCL), and using silica-based domains as cross-link points. By adopting PCL precursors with different molecular weights, semi-crystalline networks with well defined cross-link densities and with different crystallization and melting temperatures were obtained. Beside a satisfying one-way shape memory behaviour, the materials have displayed a significant two- way shape memory response, undergoing a reversible elongation-contraction process between two distinguished strain levels when subjected to a constant load and cyclically heated/cooled on a temperature region spanning from below the crystallization temperature to above the melting temperature. The applied load and the cross-link density are revealed as key-parameters to obtain tailored actuations. Concurrent wide-angle X-ray diffraction (WAXD) and DSC analyses allowed to ascribe the effect to a structural evolution process occurring during melting and crystallization.

Massimo Messori; Marco Sangermano ( 2013 ) - Organic–Inorganic Hybrid Coatings with Enhanced Scratch Resistance Properties Obtained by the Sol–Gel Process ( - Polymer Nanocomposite Coatings ) (CRC Press Inc Bosa Roca/US USA ) - pp. da 79 a 99 ISBN: 1466557303; 9781466557314 | 9781466557314 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

State of the art of organic–inorganic hybrid coatings with enhanced scratch resistance properties obtained by the sol–gel process

M. Messori; F. Bondioli ( 2013 ) - Ottimizzazione di formulazioni per applicazioni di impasti a base di argille crude come materiale da rivestimento [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Il presente progetto di ricerca riguarda lo studio e l'ottimizzazione di formulazioni per sistemi di rivestimento a base di argille crude e resine termoindurenti (resine epossidiche e/o poliuretaniche). In particolare verranno studiate e definite le proprietà chimico-fisiche dei materiali e le condizioni di lavorabilità più adatte a rispondere alle varie richieste sia nell'applicazione a pavimento che a rivestimento verticale.

M. Sangermano; P. Allia; P. Tiberto; G. Barrera; F. Bondioli; N. Florini; M. Messori ( 2013 ) - Photo-cured epoxy networks functionalized with Fe3O4 generated by non-hydrolytic sol-gel process - MACROMOLECULAR CHEMISTRY AND PHYSICS - n. volume 214 - pp. da 508 a 516 ISSN: 1521-3935 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Magnetite nanoparticles were prepared by means of non hydrolytic sol-gel (NHSG) process in the presence of benzyl alcohol. The obtained magnetite suspensions were mixed with an aliphatic epoxy resin and the formulations were photopolymerized to achieve composite materials with magnetic properties. The prepared magnetite nanoparticles and epoxy composites were fully characterized in terms of their magnetic properties.

Davide Morselli; Federica Bondioli; Adriaan S. Luyt; Thabang H. Mokhothu; Massimo Messori ( 2013 ) - Preparation and characterization of EPDM rubber modified within situgenerated silica - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 128 - pp. da 2525 a 2532 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This article is concerned with the preparation of a filled elastomer by means the nonconventional bottom-up approach to polymer composites, alternatively with the conventional mechanical compounding of preformed filler particles with rubber. EPDM rubber was modified with in situ generated silica particles prepared by means of a sol–gel process adopting a solution process. The used synthetic procedure permitted the preparation of highly filled rubbers (up to 40 wt % of silica) with silica particle dimensions ranging from 0.2 to 2 um. Equilibrium swelling and extraction tests indicated a hindering effect of the presence of in situ generated silica on the vulcanization process which reduced the cross linking degree of the rubber matrix. Both tensile tests and dynamic–mechanical analysis showed a significant improvement in the mechanical properties due to the presence of the reinforcing filler, with an enhancement more significant than that expected from a simple hydrodynamic reinforcing mechanism.

A. Spaggiari; D. Castagnetti; G. Scire' Mammano; E. Dragoni; M. Messori; P. Fabbri ( 2013 ) - Thermo-Mechanical analyses of the capillary extrusion process: chemical and mechanical aspects of coiling problem [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Comprensione ed alla ricerca sperimentale della motivazione dei difetti di produzione che compromettono l'integrità meccanica dei capillari in poliuretano, con particolare attenzione al fenomeno dell'adesione durante la fase di roccatura

D. Morselli; F. Bondioli; M. Messori ( 2012 ) - Gomma EPDM rinforzata con silice generata in-situ ( XI Convegno Nazionale AIMAT - Gaeta - 16-19 Settembre 2012) ( - Atti XI Convegno Nazionale AIMAT ) (Tipografia Pontone Cassino (FR) ITA ) - pp. da 387 a 390 ISBN: 9788897930037 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

gomma EPDM è stata rinforzata generando silice in situ mediante tecnica sol-gel. Il processo in soluzione adottato ha permesso l’ottenimento di campioni a elevata quantità di filler (fino a un 30% in peso). Sia il test a trazione che il comportamento dinamico meccanico hanno dimostrato un netto miglioramento delle proprietà meccaniche dovuto alla presenza del filler rigido in grado di rinforzare la matrice gommosa. Dalle prove a trazione è stato trovato un modulo elastico iniziale significativamente incrementato se confrontato a quello teorico calcolato dall’equazione di Smallwood-Guth-Einstein considerando un semplice meccanismo di rinforzo idrodinamico.

F. Bignotti; S. Borsacchi; R. de Santis; M. Geppi; M. Messori; U. P. Sudhakaran ( 2012 ) - Interrelation between preparation conditions, structure, and mechanical reinforcement in isoprene rubber filled with in situ generated silica - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 126 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The sol–gel technique was used to reinforce isoprene rubber (IR) by generating silica in situ from tetraethoxysilane (TEOS). The aim of the research was to elucidate the effect of the preparation conditions on the structural and morphological characteristics of silica and the resulting mechanical reinforcement. The structure of the in situ generated silica was analyzed by 29Si high-resolution solid-state NMR spectroscopy, which evidenced a high condensation degree of TEOS that decreased with increasing the sol–gel reaction time. The silica dispersion became less homogeneous as the TEOS content and the reaction time were increased. The incorporation of a coupling agent (OTES, octyltriethoxysilane) in the reaction mixture promoted full conversion of TEOS. Lower particle size, better silica dispersion, and higher filler-matrix adhesion were noticed if the incorporation of OTES was delayed compared to TEOS. Uniaxial tensile tests evidenced that the tensile strength typically increased in the first 60 min of reaction and then leveled off. A similar behavior was observed for the high deformation stiffness, whereas at low deformations, the stiffness increased monotonically with the reaction time. In the vulcanizates with silica contents higher than 25 wt %, a drastic stiffness decrement was observed passing from low to high deformations. This reduction was ascribed to the disruption of the secondary filler network occurring in these materials when severely stretched.

A. Pegoretti; G. Giusti; A. Dorigato; M. Messori; F. Bondioli; ( 2012 ) - Memoria di forma elettro-attivata di compositi polimerici contenenti nanocariche conduttive ( XI Convegno Nazionale AIMAT - Gaeta - 16-19 Settembre 2012) ( - Atti XI Convegno Nazionale AIMAT ) (Tipografia Pontone Cassino ITA ) - pp. da 411 a 414 ISBN: 9788897930037 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Sono stati preparati e caratterizzati nanocompositi elettricamente conduttivi, al fine di creare un dispositivo a memoria di forma elettro-attivato. Come matrice polimerica è stata utilizzata una base epossidica, reticolata con un indurente amminico tal quale e nanocaricato con particelle di argento (Ag) generate in-situ. Per incrementare la conducibilità del materiale risultante, sono state inoltre aggiunte varie percentuali di nanoparticelle di carbon black (CB) e nanofibre di carbonio (NF). Le analisi termiche (DSC) mostrano come l’aggiunta di nanocariche carboniose porti ad un lieve abbassamento della Tg rispetto al materiale tal quale, mentre le osservazioni morfologiche (FESEM) hanno evidenziato come il carbon black (CB) tenda a creare degli agglomerati uniformemente dispersi nella matrice, con dimensioni crescenti all’aumentare del contenuto di carica. Sia il modulo elastico che le proprietà a snervamento diminuiscono con l’introduzione del CB, mentre le nanoparticelle di Ag garantiscono un interessante effetto irrigidente ed un incremento della resistenza flessionale. La presenza di CB contribuisce maggiormente all’abbassamento della conducibilità elettrica rispetto alle nanofibre di carbonio. E’ stato inoltre osservato un interessante abbassamento della resistività, dovuto all’effetto sinergico tra le nanocariche con diversa morfologia. L’introduzione di CB garantisce un rapido riscaldamento del campione per effetto Joule, mentre l’utilizzo di nanoparticelle di Ag assicura la stabilizzazione della temperatura per tempi di applicazione del voltaggio elevati. La valutazione del grado di recupero della forma su un dispositivo preparato a partire dalla composizione più interessante ha evidenziato un recupero completo della forma per tempi limitati (< 60 s) con una tensione di 220 V.

Ignazio Roppolo; Massimo Messori; Sandrine Perruchas; Thierry Gacoin; Jean-Pierre Boilot; Marco Sangermano ( 2012 ) - Multifunctional Luminescent Organic/ Inorganic Hybrid Films - MACROMOLECULAR MATERIALS AND ENGINEERING - n. volume 297 - pp. da 680 a 688 ISSN: 1438-7492 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Transparent light-emitting hybrid materials are produced by UV curing of acrylic resins containing silica precursors and photoluminescent [Cu4I4L4] clusters. Acrylic double-bond conversion is followed by means of FT-IR spectroscopy, and optical measurements are performed on cured films showing a high transparency of the films up to a content of 30wt% TEOS and a bright luminescence with a maximum of emission centered at 565nm (yellow-orange). This study shows the possibility to obtain new advanced materials in which functional properties such as photoluminescence and scratch resistance are successfully conjugated in a hybrid film that maintains high transparency.

D. Morselli; F. Bondioli; M. Sangermano; M. Messori ( 2012 ) - Photo-cured epoxy networks reinforced with TiO2 in-situ generated by means of non-hydrolytic sol-gel process - POLYMER - n. volume 53 - pp. da 283 a 290 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Suspensions of titania nanoparticles in benzyl alcohol were synthesised from TiCl4 by means of non- hydrolytic sol-gel (NHSG) process. The stable suspensions were mixed with an aliphatic epoxy resin and subsequently photo-polymerised in the presence of a cationic photo-initiator to produce transparent composite films. The presence of titania didn’t influence significantly the polymerisation rate, while a progressive decrease in the maximum value of epoxy groups conversion was observed by increasing the titania content. Gel content analysis demonstrated that all organic species (benzyl alcohol and corresponding by-products) were covalently linked to the epoxy network, suggesting that both ‘active chain end’ and ‘activated monomer’ mechanisms were active during the propagation step in the cationic ring- opening polymerisation. The presence of titania increased significantly both glass transition temperature and modulus (in the rubbery region) confirming the reinforcing and stiffening effect due to both the presence of inorganic nanofillers and, most importantly, a higher cross-linking density of the composite material with respect to the pristine epoxy matrix. Nano-indentation and scratch tests also showed a systematic increase of hardness and scratch resistance by increasing the filler content.

T.E. Motaung; A.S. Luyt; F. Bondioli; M. Messori; M.L. Saladino; A. Spinella; G. Nasillo; E. Caponetti ( 2012 ) - PMMA-titania nanocomposites: Properties and thermal degradation behaviour - POLYMER DEGRADATION AND STABILITY - n. volume 97 - pp. da 1325 a 1333 ISSN: 0141-3910 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Titania nanoparticles were prepared using a sol-gel method and calcination at 200 and 600 C in order to obtain anatase and rutile phases, respectively. The obtained powders were used to prepare PMMA-titania nanocomposites by a melt compounding method. The effect of the crystalline phase and the amount of titania, in the range 1-5 wt.%, on the morphology, mechanical properties and thermal degradation kinetics of PMMA was investigated by means of X-ray diffractometry (XRD), transmission electron microscopy (TEM), 13C cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy (13C{1H}CP-MAS NMR), including the measurement of proton spin-lattice relaxation time in the rotating frame (T1ρ(H)), in the laboratory frame (T1(H)) and cross polarization times (TCH), and dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and Fourier-transform infrared (FTIR) spectroscopy. Results showed that both types of titania were well dispersed in the polymeric matrix, whose structure remained amorphous. The two types of nanoparticles influenced the degradation of the polymer in different ways because of their different carbon content, particle size and crystal structures.

D. Morselli; F. Bondioli; M. Fiorini; M. Messori ( 2012 ) - Poly(methyl methacrylate)–TiO2 nanocomposites obtained by non-hydrolytic sol–gel synthesis: the innovative tert-butyl alcohol route - JOURNAL OF MATERIALS SCIENCE - n. volume 47 - pp. da 7003 a 7012 ISSN: 0022-2461 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The present article concerns the preparation of poly(methyl methacrylate)/titania nanocomposites by a non-conventional bottom-up approach, as alternative to the conventional mechanical compounding of preformed filler particles. Poly(methyl methacrylate) (PMMA) was modi- fied with in situ generation of titania nanoparticles by means of the so-called non-hydrolytic sol–gel (NHSG) process in the presence of tert-butyl alcohol (tBuOH) as oxygen donor and polymer solvent. The results showed that the synthetic procedure used permitted the preparation of the highly filled PMMA (up to 20 phr of titania in anatase form) with titania actual content values very close to the nominal ones and with enhanced filler dispersion and homogeneous distribution within the polymeric matrix, avoiding the typical rheological problems related to distributive and dispersive mixing of conventional compounding methods. The presence of titania nanoparticles led to increases in glass transition temperature and E' modulus in the rubbery region for all the prepared samples with respect to the pristine PMMA. Finally, the nano-composites showed an interesting photo-catalytic activity towards organic molecules. The findings led us to conclude that the NHSG process was successfully employed to produce anatase titania in the presence of tBuOH and PMMA. The proposed process seems to offer a very promising method to produce polymer nanocomposites with good filler dispersion and homogeneous distribution and with interesting functional properties such as photo-catalytic activity.

D. Morselli; F. Bondioli; M. Sangermano; M. Messori ( 2012 ) - Resine epossidiche rinforzate con titania generata in situ mediante processo dol-gel non idrolitico ( XI Convegno Nazionale AIMAT - Gaeta - 16-19 Settembre 2012) ( - Atti XI Convegno Nazionale AIMAT ) (Tipografia Pontone Cassino (FR) ITA ) - pp. da 391 a 394 ISBN: 9788897930037 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Sospensioni di nanoparticelle di titania in alcol benzilico sono state preparate mediante processo sol-gel non-idrolitico e miscelate a una resina epossidica alifatica. Le formulazioni ottenute sono poi state foto-polimerizzate in presenza di un foto-iniziatore cationico per produrre film nanocompositi. La presenza di titania non ha variato significativamente la velocità di foto-polimerizzazione, mentre è stata osservata una riduzione della conversione massima di gruppi epossido all'aumentare del contenuto di titania. Attraverso l'analisi del contenuto di gel è stato evidenziato che tutte le specie organiche presenti (alcol benzilico e relativi sottoprodotti) sono covalentemente legati al reticolo epossidico indicando che entrambi i meccanismi 'active chain end' e 'activated monomer' sono attivi nella fase di propagazione della polimerizzazione cationica per apertura di anello. La presenza di titania ha portato a significativi aumenti sia della temperatura di transizione vetrosa che del modulo e questo effetto di rinforzo è stato attribuito, oltre che all'atteso effetto idrodinamico legato alla presenza di particelle rigide, anche a una maggiore densità di reticolazione nel materiale composito rispetto alla resina epossidica pura.

K. Paderni; S. Pandini; S. Passera; F. Pilati; M. Toselli; M. Messori ( 2012 ) - Shape-memory polymer networks from sol–gel cross-linked alkoxysilane-terminated poly(e-caprolactone) - JOURNAL OF MATERIALS SCIENCE - n. volume 47 - pp. da 4354 a 4362 ISSN: 0022-2461 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A novel type of covalently cross-linked semi- crystalline polymer with shape-memory and biocompatibility properties was prepared from alkoxysilane-terminated poly(e-caprolactone) (PCL) by sol–gel process that allowed the generation of silica-like cross-linking points. A fine tuning of the cross-linking density and thermal properties (melting temperature) of the materials was obtained by controlling the molecular weight of the PCL precursor (and thus the molecular structure of the resulting network) and the curing conditions. The shape-memory behaviour was investigated with bending tests. Recovery times of less than one second were observed in water depending on the temperature, and a linear correlation of the recovery time with cross-linking density and molecular weight of PCL network precursor was observed.

M. Sangermano; F. Sordo; M. Messori ( 2012 ) - Surface Property Modification of Epoxy Coatings by Polydimethylsiloxanes - MACROMOLECULAR MATERIALS AND ENGINEERING - n. volume 297 - pp. da 257 a 262 ISSN: 1438-7492 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Surface properties of epoxy coatings are modified by PDMS additives in cationic UV curing of a cycloaliphatic epoxy resin. The cured films show a very high hydrophobicity that does not depend on PDMS concentration, indicating that a threshold is reached even at 0.3wt% additive. A slight increase of the water contactangle as a function of PDMS molecular weight is observed. The additive selectively modified the air-side of the film, while the glass-side retains the surface properties of the pure resin. This segregation phenomenon permits to obtain highly hydrophobic films with still good adhesion properties on polar substrates, which is an important advantage over common surface-modified resins.

Pandini, Stefano; Passera, Simone; Riccò, Theonis; Borboni, Alberto; Bodini, Ileana; Vetturi, David; Dassa, Luca; Cambiaghi, Danilo; Paderni, Katia; Degli Esposti, Micaela; Toselli, Maurizio; Pilati, Francesco; Messori, Massimo ( 2012 ) - Tailored One-Way and Two-Way Shape Memory Response of Poly(ε-Caprolactone)-Based Systems for Biomedical Applications ( Symposium A on Adaptive, Active and Multifunctional Smart Materials Systems of CIMTEC / 4th International Conference on Smart Materials, Structures and Systems - Montecatini Terme, ITALY - JUN 10-14, 2012) ( - ADAPTIVE, ACTIVE AND MULTIFUNCTIONAL SMART MATERIALS SYSTEMS ) - ADVANCES IN SCIENCE AND TECHNOLOGY - n. volume 77 - pp. da 313 a 318 ISSN: 1662-0356 [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

A series of crosslinked poly(epsilon-caprolactone) (PCL) materials were obtained starting from linear, three- and four-arm star PCL functionalized with methacrylate end-groups, allowing to tune the melting temperature (T-m) on a range between 36 and 55 degrees C. After deforming the specimens at 50% above T-m, the materials are seen to fully restore their original shape by heating them on a narrow region close to T-m; further, when the shape memory effect is triggered under fixed strain conditions, the materials are able to exert stress on a range between 0.2 and 7 MPa. The materials also display two-way shape memory features, reversibly moving between two shapes when cooled and heated under a fixed load. Finally, to investigate the application of the PCL materials as self-expandable stents, one-way shape memory experiments are currently carried out on tubular specimens.

S. Pandini; S. Passera; M. Messori; K. Paderni; M. Toselli; A. Gianoncelli; E. Bontempi; T. Riccò ( 2012 ) - Two-way reversible shape memory behaviour of crosslinked poly(ε-caprolactone) - POLYMER - n. volume 53 - pp. da 1915 a 1924 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Polymers capable of reversible “two-way” shape memory behaviour are of great interest for applications where reversible actuation is demanded, and semicrystalline crosslinked systems have been indicated as an interesting solution towards this end. In this work we have explored the two-way shape memory response of semicrystalline poly(ε-caprolactone)-based polymer networks, prepared with various macromolecular architectures starting from linear, three- and four-arm star poly(ε-caprolactone) functionalized with methacrylate end-groups. All the materials have revealed two-way shape memory capabilities. The effect arises from an elongation process that takes place when the material is cooled under an applied load below the crystallization temperature, and that is completely reversed when heated again above melting temperature, in a manner that strongly depends on the applied load and on the material crosslink density. Two-dimensional XRD analysis, carried out on elongated specimens, shows that the elongation on cooling is accompanied by a change in the crystallinity orientation along the direction of stretch.

M. Messori; F. Pilati; M. Toselli; F. Bisi; M. Dinelli ( 2012 ) - Valutazione di nuovi materiali per l’enologia [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

AZIONE n. 1: Sviluppo di una procedura innovativa per la produzione di vino a bassa gradazione alcolica AZIONE n. 2: Sviluppo di una procedura innovativa per il miglioramento della qualità/conservazione del vino

M. Sangermano; E. Gaspari; L. Vescovo; M. Messori ( 2011 ) - Enhancement of scratch-resistance properties of methacrylated UV-cured coatings - PROGRESS IN ORGANIC COATINGS - n. volume 72 - pp. da 287 a 291 ISSN: 0300-9440 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Methacrylic based organic–inorganic hybrid coatings containing silica, titania or alumina domains, were generated in situ combining a UV-induced polymerization reaction with a sol–gel process of metal alkoxide precursors. While the presence of TEOS and ALP did not influence significantly the rate of curing and the final methacrylic double bond conversion, a certain effect is evident when TIP is added as inorganic precursor both on UV-curing rate and final double bond conversion. An increase of the rigidity of the cured coating was achieved in the presence of the inorganic fillers with an increase of Tg values by increasing the metal alkoxide content in the photocurable formulations. Scratch test showed a general increase of first and second critical load values for hybrid coatings together with an increase in the Persoz hardness values.

Federica Bondioli; Maria Elena Darecchio; Adrian S. Luyt; Massimo Messori ( 2011 ) - Epoxy resin modified with in situ generated metal oxides by means of sol–gel process - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 122 - pp. da 1792 a 1799 ISSN: 1097-4628 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic–inorganic hybrids were prepared with silica, zirconia, or titania in situ generated within epoxy resins based on bisphenol A diglycidyl ether and Jeffamine® by means of the aqueous sol–gel process. The morphology of the prepared hybrids varied from a particulate dispersed phase to a co-continuous morphology. Silica and zirconia filled epoxies were characterized by a significant increase in thermal stability, attributable to the high thermal stability of silica and zirconia phases. On the contrary, the introduction of titania induced a strong decrease in thermal stability of the epoxy/titania hybrids compared with the pure epoxy resin, attributable to metal-catalyzed oxidative decomposition mechanism in the polymer/titania composite. Hybrids were much more transparent than unfilled epoxy. The transmittance of silica- and titania-based hybrids showed a slight decrease by increasing the content of filler, while the transparency of zirconia-based hybrids was very high and almost constant independently by the nominal content of filler. The presence of in situ generated fillers significantly enhanced the scratch resistance of the epoxy resin as indicated by the marked increase of critical load for all the hybrids.

Mauro Comes-Franchini; Massimo Messori; Guido Ori; Cristina Siligardi ( 2011 ) - Flame retardant SBS-clay nanocomposites ( - Thermally Stable and Flame Retardant Polymer Nanocomposite ) (Vikas Mittal Cambridge GBR ) - pp. da 360 a 382 ISBN: 9780521190756 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Polymer nanocomposites have revolutionized material performance, most notably in the plastcs, automotive, and aerospace industries. In this book leaders in the field outline the mechanism behind the generation of suitable polymer systems, pulling together recent research to provide a unified and up-to-date assessment of recent technological advances.

M. Messori; F. Bondioli; K. Paderni; D. Morselli; P. Fabbri ( 2011 ) - In situ generation of fillers within polymer matrices: an innovative way to reinforced plastics [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Massimo Messori ( 2011 ) - In Situ Synthesis of Rubber Nanocomposites ( - Recent Advances in Elastomeric Nanocomposites ) (Springer-Verlag Berlin Heidelberg DEU ) - n. volume 9 - pp. da 57 a 85 ISBN: 9783642157875 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

The preparation and characterization of rubber based nanocomposites prepared by in situ generation of inorganic oxides by means of the hydrolytic sol– gel process are reviewed in the present chapter. The sol–gel approach has been applied to several rubber matrices to prepare reinforced vulcanized and unvul- canized rubbers. Several synthetic procedures are presented while the most investigated filler is silica obtained by hydrolysis and condensation of tetraeth- oxysilane. The effects of the different preparation conditions and of the filler content are generally discussed in terms of morphology (investigated by electron microscopy and small angle X-ray scattering) and mechanical properties (modulus, strength and extensibility). The mechanical properties of the in situ filled nano- composites are generally better than those of the corresponding materials prepared with the conventional mechanical mixing of preformed particulates and elasto- mers. This enhancement is generally attributed to a lower tendency to filler–filler aggregation due to a lower particle surface interaction resulting from the ‘bottom- up approach’ of the sol–gel process applied to the preparation of organic–inorganic hybrid materials.

Massimo Messori; Maurizio Fiorini ( 2011 ) - Isoprene Rubber Filled with Silica Generated In Situ - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 119 - pp. da 3422 a 3428 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

We modified synthetic isoprene rubber by means of the in situ generation of silica particles through the sol–gel process starting from tetraethoxysilane (TEOS) as an inorganic oxide precursor. Different reaction condi- tions were investigated with variations in the initial TEOS content, the reaction time of the sol–gel process, and the presence of a coupling/surfactant agent (octyltriethoxy- silane). Organic–inorganic hybrid materials with a silica content up to 70 phr were obtained with the complete con- version of TEOS to silica for a long enough sol–gel reac- tion time. A very homogeneous dispersion of silica particles was observed in all cases together with a very good adhesion between the filler and matrix. The size of the in situ generated silica was controlled by the appropri- ate addition of octyltriethoxysilane. Swelling and extrac- tion tests and dynamic mechanical analysis indicated that the vulcanization process of isoprene rubber was per- turbed by the sol–gel process; this led to a slight decrease in the crosslinking degree. However, a significant reinforc- ing effect due to the presence of silica particles was observed for all of the investigated samples.

M. Messori; P. Fabbri; F. Pilati; C. Tonelli; M. Toselli ( 2011 ) - Perfluoropolyether-based organic–inorganic coatings - PROGRESS IN ORGANIC COATINGS - n. volume 72 - pp. da 461 a 468 ISSN: 0300-9440 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In the present paper a comprehensive analysis on the preparation and characterization oforganic–inorganic hybrids containing perfluoropolyethers (PFPE) as organic component and silica (in situgenerated from tetraethoxysilane by means of the sol–gel process) as inorganic counterpart is reported.PFPE with different molecular weights and functionalities have been used in order to improve the miscibilitywith respect to other reactants and solvents comprising the final formulation of the coating. Inthis respect, PFPE oligomers have been used with or without chain extension with polycaprolactonesegments. The hybrids have been applied with different techniques onto glass substrates as functionalcoatings and the effects of different molecular structures, molecular weights and organic–inorganic ratioshave been thoroughly investigated in terms of surface properties (i.e. water and oil wettability and surfacesegregation of PFPE segments).

A.S. Luyt; M. Messori; P. Fabbri; J.P. Mofokeng; R. Taurino; T. Zanasi; F. Pilati ( 2011 ) - Polycarbonate reinforced with silica nanoparticles - POLYMER BULLETIN - n. volume 66 - pp. da 991 a 1004 ISSN: 0170-0839 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Nanocomposites of polycarbonate (PC) reinforced with nanosized silica particles were prepared by a melt mixing technique in an internal mixer. Two kinds of commercial hydrophilic fumed silicas differing in their specific surface area were added in amounts up to 5% by volume, and their reinforcing action was compared to that of organically modified silica, loaded in the same amounts. Particle–matrix interactions were investigated by means of rheological and dynamic-mechanical thermal analysis, demonstrating the important role played by the organic modifi- cation in the interactions with the polymer matrix, and showing an optimal nano- particle loading around 2 vol%. The scratch resistance of the nanocomposites obtained from hydrophilic silicas was investigated, and a remarkable enhancement in the indenter’s penetration resistance was observed for all the compositions with respect to pristine PC. The same behaviour was observed for the Shore D hardness and for the impact resistance of the nanocomposites that also significantly improved with the maximum load shifting from a minimum value of 521 N for pristine PC up to values grater than 1330 N for the nanocomposites, demonstrating the activation of effective mechanisms of energy dissipation due to the presence of the nanofillers.

D. Morselli; M. Messori; F. Bondioli ( 2011 ) - Poly(methyl methacrylate)-TiO2 nanocomposite obtained by non-hydrolytic sol–gel synthesis - JOURNAL OF MATERIALS SCIENCE - n. volume 46 - pp. da 6609 a 6617 ISSN: 0022-2461 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(methyl methacrylate) (PMMA)/titanium dioxide (TiO2) nanocomposites were prepared by means of in situ generation of TiO2 through a non-hydrolytic sol–gel process (NHSG), starting from titanium chloride, as titania precursor, benzyl alcohol, as oxygen donor, and commer- cial PMMA. TiO2 nanoparticles (average size of 30 nm) were obtained in the anatase and amorphous forms. The in situ generation led to a very homogeneous distribution of particulate fillers within the polymeric matrix avoiding the problems related to distributive and dispersive mixing of conventional compounding methods (top down approach). A slight increase of glass transition temperature was observed for all prepared composites with respect to the pristine PMMA. The NHSG process did not affect the molecular weight of the polymers indicating the absence of any degradation reaction for PMMA. The presence of titania in the anatase phase increases the photodegradation of the PMMA matrix due to UV irradiation.

M. Colonna; C. Berti; E. Binassi; A. Celli; M. Fiorini; P. Marchese; M. Messori; D.J. Brunelle ( 2011 ) - Poly(1,4-cyclohexylenedimethylene-1, 4-cyclohexanedicarboxylate): analysis of parameters affecting polymerization and cis-trans isomerization - POLYMER INTERNATIONAL - n. volume 60 - pp. da 1607 a 1613 ISSN: 0959-8103 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Weatherable semicrystalline polyesters based on 1,4-cyclohexanedimethanol, 1,4-cyclohexanedicarboxylic acid (CHDA) or dimethyl 1,4-cyclohexane dicarboxylate (DMCD) can be prepared under normal melt-phase conditions, using titanium tetrabutoxide as catalyst. The effect of monomer ratio, reaction temperature and catalyst loading on the final polymer properties was studied. Under the proper polymerization conditions, poly(1,4-cyclohexylenedimethylene-1,4-cyclohexanedicarboxylate) polymers with high molecular weight can be obtained. During polymerization, isomerization can occur towards the thermodynamically stable cis-trans ratio of 34-66 mol%. Carboxylic acid end groups can catalyze the isomerization and therefore the polymerization is more critical starting from CHDA rather than DMCD. Moreover, temperature control becomes a key factor to avoid or to limit isomerization. The study of the isomerization of the different monomers permitted a better understanding of the isomerization and therefore of the polymerization process.

S. Werner; D. Pospiech; D. Jehnichen; K. Eckstein; H. Komber; P. Friedel; A. Janke; F. Näther; U. Reuter; B. Voit; R. Taurino; M. Messori ( 2011 ) - Synthesis and Phase-Separation Behavior of a,x-Difunctionalized Diblock Copolymers - JOURNAL OF POLYMER SCIENCE. PART A, POLYMER CHEMISTRY - n. volume 49 - pp. da 926 a 937 ISSN: 1099-0518 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A series of diblock copolymers of n-pentyl methacrylate and methyl methacrylate (PPMA/PMMA BCP) with one or two terminal functional groups was prepared by sequential anionic polymerization of PMA and MMA using an allyl-functionalized initiator and/or and end-capping with allyl bromide. Allyl functional groups were successfully converted into OH groups by hydroboration. The morphology in bulk was examined by temperature-dependent small-angle X-ray measurements (T-SAXS) and transmission electron microscopy (TEM) showing that functional groups induced a weak change in d-spacings L-0 as well as in the thermal expansion behavior. T-SAXS proved that the lamellar morphologies were stable over multiple heating cooling cycles without order-disorder transition (ODT) until 300 degrees C. While non-functionalized BCP formed parallel lamellae morphologies, additional OH-termination at the PMMA block forced in very thin films (ratio between film thickness and lamellar d-spacing below 1) the generation of perpendicular lamellae morphology through the whole film thickness, as shown by Grazing-incidence small-angle X-ray scattering experiments (GISAXS) measurements. Functionalized BCP were successfully used in thin films as templates for silica nanoparticles in an in-situ sol-gel process.

Dorigato, A.; Pegoretti, A.; Bondioli, Federica; Messori, Massimo ( 2010 ) - Improving Epoxy Adhesives with Zirconia Nanoparticles - COMPOSITE INTERFACES - n. volume 17 - pp. da 873 a 892 ISSN: 0927-6440 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Zirconia nanoparticles were synthesized by a sol–gel route and dispersed into an epoxy base for struc- tural adhesives. Nanoparticles were used as-synthesized or after calcination. Moreover, the effect of silane functionalization was also investigated. According to preliminary tensile mechanical tests on bulk nanocom- posite samples, calcined and untreated zirconia nanoparticles were selected for the preparation of adhesives with various filler contents.The glass transition temperature increased up to a filler content of 1 vol% and then decreased, probably due to the concurrent and contrasting effects of chain blocking and reduction of the crosslinking degree. Also tensile modulus, stress at break and fracture toughness of bulk adhesives samples were positively affected by the presence of an optimal amount of zirconia nanoparticles.Mechanical tests on single lap aluminium bonded joints indicated that zirconia nanoparticles led to rele- vant enhancements of the shear strength of the joints. In particular, the shear strength increased by about 60% for an optimal filler content of 1 vol%, and an adhesive failure mechanism was evidenced for all the tested specimens. Concurrently, a significant decrease of the equilibrium contact angle with water was observed for adhesives containing zirconia nanoparticles. It can therefore be concluded that the addition of zirconia nanoparticles can effectively improve epoxy adhesives, both by increasing their mechanical properties and by enhancing the interfacial wettability with an aluminium substrate.

Fabbri, Paola; Bondioli, Federica; Messori, Massimo; Bartoli, C.; Dinucci, D.; Chiellini, F. ( 2010 ) - Porous scaffolds of polycaprolactone reinforced with in situ generated hydroxyapatite for bone tissue engineering - JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE - n. volume 21 - pp. da 343 a 351 ISSN: 0957-4530 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Polycaprolactone/hydroxyapatite (PCL/HA) composites were prepared by in situ generation of HA in the polymer solution starting from the precursors calcium nitrate tetrahydrate and ammonium dihydrogen phosphate via sol–gel process. Highly interconnected porosity was achieved by means of the salt-leaching technique using a mixture of sodium chloride and sodium bicarbonate as porogens. Structure and morphology of the PCL/HA composites were investigated by scanning electron microscopy, and mechanical properties were determined by means of tensile and compression tests. The possibility to employ the developed composites as scaffolds for bone tissue regeneration was assessed by cytotoxicity test of the PCL/HA composites extracts and cell adhesion and pro- liferation in vitro studies.

Sangermano, M.; Messori, Massimo ( 2010 ) - Scratch Resistance Enhancement of Polymer Coatings - MACROMOLECULAR MATERIALS AND ENGINEERING - n. volume 295 - pp. da 603 a 612 ISSN: 1438-7492 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This review presents the state of the art regarding the improvement of scratch resistance of polymeric coatings. In particular, our attention is focused on the effect of inorganic nano- metric fillers on the scratch resistance of organic coatings. Two main strategies are described for the achievement of such nanostructured hybrid organic/inorganic coatings: either a top- down or a bottom-up approach.

Sangermano, M.; Messori, Massimo; Rizzoli, A.; Grassini, S. ( 2010 ) - UV-cured epoxy coatings modified with perfluoropolyether-based materials - PROGRESS IN ORGANIC COATINGS - n. volume 68 - pp. da 323 a 327 ISSN: 0300-9440 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Hydroxy terminated PFPE were chain extended with short PCL segments in order to enhance the com- patibility towards the epoxy resin. The obtained PFPE–PCL block copolymers were used as additives to modify toughness of a UV curable bisphenol-A-based epoxy coating. A certain degree of phase separation was achieved during UV curing. The morphology of the obtained cured materials depends on the poly- caprolactone PCL length. The perfluoropolyether PFPE additive, without any PCL segment (additive TX), clearly showed a biphasic morphology with separated domains within 50–100 um. By increasing the PCL segment it was not identified any second distinct phase. It was shown that the addition of TX additive can generate a strong phase separation and this allowed to achieve an improvement of the toughness properties of the cured samples without affecting the thermo-mechanical properties.

M. Messori ( 2010 ) - Verniciatura di substrati plastici ( - Rivestimenti polimerici - Materiali, tecnologie e proprietà ) (Edizioni Nuova Cultura Roma ITA ) - pp. da 235 a 245 ISBN: 9788861344617 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Atti del XXXI Convegno Scuola AIM Mario Farina su “Rivestimenti polimerici - Materiali, tecnologie e proprietà” - 17-20 Maggio 2010, Gargnano (BS)

P. Fabbri; M. Messori; M. Toselli; P. Veronesi; J. Rocha; F. Pilati ( 2009 ) - Enhancing the scratch resistance of polycarbonate with poly(ethylene oxide)-silica hybrid coatings - ADVANCES IN POLYMER TECHNOLOGY - n. volume 27 (2) - pp. da 117 a 126 ISSN: 0730-6679 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Scratch-resistant coatings for bisphenol-A polycarbonate sheets were obtained by the sol–gel synthesis of an organic–inorganic hybrid system based on poly(ethylene oxide) and silica. The organic–inorganic hybrids were thermally cured into hard transparent coatings by using conventional and microwave (MW) ovens. Both techniques proved to be equally efficient in promoting the system’s crosslinking, as evaluated by 29Si MAS-NMR. The MW-assisted curing, however, was much faster. Photoelasticity analysis showed that MW-assisted curing causes localized overheating of the samples, inducing a state of residual plane stresses that bring about dimensional instability of the coated material. Instrumented scratch tests for the coated samples revealed an increase of 1 order of magnitude in the minimal load at which a scratch track appears on the sample surface. However, the friction coefficient values for samples with thermally cured coatings were lower than those produced by MW-assisted curing.

F. Bondioli; A. Dorigato; P. Fabbri; M. Messori; A. Pegoretti ( 2009 ) - Improving the creep stability of high-density polyethylene with acicular titania nanoparticles - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 112(2) - pp. da 1045 a 1055 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Acicular titania nanoparticles with average dimensions of 15 X 60 nm2 were produced by hydrothermal crystallization of TiOCl2. Titania particles were surface- functionalized with octadecylsilane to obtain an organophilic surface. High-density polyethylene (HDPE) nanocomposites were prepared by melt compounding with 2, 3, and 5 vol % concentrations of untreated and surface-functionalized titania nanoparticles. Quasi-static mechanical tensile tests evidenced slight increments of both the elastic modulus and stress at yield, which were accompanied by a marked reduction of the strain at break at high filler contents. The introduction of titania nanoparticles induced a substantial reduction of the creep compliance of the HDPE matrix and of its creep rate, especially at long loading times. Untreated titania nanoparticles were more effective in reducing the creep compliance than the functionalized ones.

M. Messori; F. Bignotti; R. De Santis; R. Taurino ( 2009 ) - Modification of isoprene rubber by in situ silica generation - POLYMER INTERNATIONAL - n. volume 58 - pp. da 880 a 887 ISSN: 0959-8103 [Articolo in rivista (262) - Articolo su rivista]
Abstract

BACKGROUND: The reinforcement of elastomers by the addition of fillers is one of the most important aspects in rubber science and technology. In order to optimise the filler – polymer interface, innovative in situ generation of silica within isoprene rubber was carried out by means of a bottom-up approach through a sol – gel process starting from tetraethoxysilane as silica precursor. The main aim was the study of the effect of the silica concentration and of the presence of coupling agent on the morphology and the dynamic mechanical behaviour of the composites.RESULTS: The in situ generated silica particles were homogeneously dispersed in the vulcanised rubber with dimensions from a few nanometres to the submicrometre scale. In the presence of coupling agent a good polymer – filler adhesion was observed. The dynamic mechanical behaviour was nonlinear for silica contents higher than 20 wt%. In this range of compositions silica exerted a marked reinforcement on the low-amplitude storage modulus, which is related to the silica content according to the Huber–Vilgis model.CONCLUSION: Isoprene rubber can be effectively reinforced by the in situ generation of silica for silica contents higher than 20 wt%, and the interaction at the silica – rubber interface can be optimised by using suitable coupling agents.

M. Iotti; P. Fabbri; M. Messori; F. Pilati; P. Fava ( 2009 ) - Organic–Inorganic Hybrid Coatings for the Modification of Barrier Properties of Poly(lactic acid) Films for Food Packaging Applications - JOURNAL OF POLYMERS AND THE ENVIRONMENT - n. volume 17 - pp. da 10 a 19 ISSN: 1566-2543 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic–inorganic hybrid coatings based on poly(e-caprolactone), poly(ethylene oxide) or poly(lactic acid) as organic phase and silica from tetraethoxysilane as inorganic phase were prepared by the sol–gel approach. Coatings were applied onto poly(lactic acid) films for food packaging in order to improve its barrier properties towards oxygen and water vapour. All the prepared coatings were dense, homogeneous layers characterized by a good adhesion to the substrate. The permeance of the coating layers resulted one order of magnitude lower than that of the uncoated poly(lactic acid) (PLA) film. The hydrophilic character of the coating did not permit to gain a significant decrease in the water vapour permeance. The perfect visual transparency of the coatings allows their application without worsening of the esthetical properties of the sub- strate PLA film.

Sangermano, M.; Messori, Massimo; Martin Galleco, M.; Rizza, G.; Voit, B. ( 2009 ) - Scratch resistant tough nanocomposite epoxy coatings based on hyperbranched polyesters - POLYMER - n. volume 50 - pp. da 5647 a 5662 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Advanced multifunctional coatings were prepared by UV curing of epoxy based formulations containing hyperbranched polymers (HBP) and an epoxy functionalized alkoxysilane additive. The addition of HBP to the UV curable epoxy resin induced an important flexibilization of the glassy epoxy network with an increase in toughness of the cured polymeric coatings. Adding the functionalized alkoxysilane into the UV curable formulations, as inorganic precursor of silica phase, an improvement on surface hardness was obtained without strongly affecting the flexibilization and the toughness achieved by the addition of the HBP additive. The increase on surface hardness was accompanied with an increase in scratch resistance and modulus. Advanced scratch resistant and tough nanocomposite epoxy coatings were obtained by properly selecting the components of the formulation.

M. Comes Franchini; P. Fabbri; A. Frache; G. Ori; M. Messori; C. Siligardi; A. Ricci ( 2008 ) - Bentonite-based organoclays as innovative flame retardants agents for SBS copolymer - JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY - n. volume 8 - pp. da 6316 a 6324 ISSN: 1533-4880 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Two organophilic bentonites, based on nitrogen-containing compounds, have been synthesised viaion exchange starting from pristine bentonite with octadecyltrimethylammonium bromide (OTAB)and with synthetic melamine-derived N2,N4-dihexadecyl-1,3,5-triazine-2,4,6-triamine (DEDMEL).The chemical and morphological characterization of the organoclays was based on XRD, TEM,Laser Granulometry, X-Ray Fluorescence and CEC capacity. Copoly(styrene-butadiene-styrene)-nanocomposites (SBS-nanocomposites) were obtained by intercalation of the SBS-copolymer intothese new organoclays by melt intercalation method. XRD and TEM analysis of the organoclaysand of the micro/nano-composites obtained are presented. The effect of the organoclays on theSBS-nanocomposite’s flammability properties was investigated using cone calorimeter. An encouragingdecrease of 20% in the peak heat released rate (PHRR) has been obtained confirming theimportant role of melamine’s based skeleton and its derived organoclays to act as effective fireretardants and for the improvement of this important functional property in SBS copolymers.

M. Messori; F. Pilati; P. Fabbri; M. Toselli ( 2008 ) - Epoxy resins modified with perfluoropolyethers: toughening and reduction of liquid absorption - PITTURE E VERNICI - n. volume 84 - pp. da 9 a 15 ISSN: 0048-4245 [Articolo in rivista (262) - Articolo su rivista]
Abstract

nd

R. Taurino; E. Fabbri; M. Messori; F. Pilati; D. Pospiech; A. Synytska ( 2008 ) - Facile preparation of superhydrophobic coatings by sol–gel processes - JOURNAL OF COLLOID AND INTERFACE SCIENCE - n. volume 325 - pp. da 149 a 156 ISSN: 0021-9797 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Different organic/inorganic compositions and deposition methods were used to prepare superhydrophobic surfaces using metal alkoxides and the sol–gel process. Both surface roughness and composition had to be adjusted in order to obtain very high contact angles and low contact angle hysteresis as a necessary requirement for superhydrophobicity. Multilayer samples with a fluorinated organic–inorganic top layer showed water contact angles of about 157° with low hysteresis (2°). Water drops rolled easily off their surface at a tilt angle as low as 4°.

F. BONDIOLI; DORIGATO A; FABBRI P; MESSORI M; PEGORETTI A ( 2008 ) - High-density polyethylene reinforced with titania nanoparticles (Society of Plastics Engineers:14 Fairfield Drive, PO Box 0403:Brookfield, CT 06804:(203)775-0471, INTERNET: http://www.4spe.org, Fax: (203)775-8490 ) - POLYMER ENGINEERING AND SCIENCE - n. volume 48[3] - pp. da 448 a 457 ISSN: 0032-3888 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Titania nanoparticles were prepared by means of two different synthetic procedures in order to obtain different particle size (diameter ranging from 20 nm to 350 nm), shapes and morphologies (amorphous or crystalline). Titania nanoparticles were surface modified with octadecylsilane in order to improve their compatibility with respect to polymeric matrices. High density polyethylene (HDPE) - titania nanocomposites were prepared by melt blending by using an internal mixer. The obtained nanocomposites were mechanically characterized and quasi static and creep tensile conditions. The presence of titania nanoparticles (1%vol) led to a significant increase of elastic modulus (20-25%) together with a slight increase of yield stress and a decrease of ultimate elongation. An interesting reduction of for both elastic and viscoelastic creep compliance components was also evidenced.

P. FABBRI; M. MESSORI; F. PILATI; R. TAURINO; C. TONELLI; M. TOSELLI ( 2008 ) - Hydrophobic and Oleophobic Coatings Based on Perfluoropolyether/Silica Hybrids by the Sol-Gel Method - ADVANCES IN POLYMER TECHNOLOGY - n. volume 26 - pp. da 182 a 190 ISSN: 0730-6679 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Glass substrates were spin-coated with a perfluoropolyether oligomer based organic-inorganic hybrid material, and prepared by the sol-gel process. Contact angle analysis and atomic force microscopic analysis were carried out to characterize the surface of the prepared coatings. All systems exhibited strong hydrophobic and oleopophobic characteristics. The wettability behavior was found to be almost independent of both molecular weight and functionality of the fluorinated oligomer. The low values obtained for the contact angle and surface tension indicate that surface segregation of perfluoropolyether segments is likely to take place within the network. On the basis of these results and the high quality of the obtained coatings, these materials could be used as functional coatings to impart water and oleo-repellent characteristics to glasses and other similar substrates.

FABBRI P; LEONELLI C; MESSORI M; F. PILATI; TOSELLI M; VERONESI P; MORLAT-THERIAS S; RIVATON A; GARDETTE J.L ( 2008 ) - Improvement of the surface properties of polycarbonate by organic-inorganic hybrid coatings - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 108(3) - pp. da 1426 a 1436 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic-inorganic hybrids (ceramers) were prepared through the sol-gel process with opportune alkoxysilane-terminated polymer chains as the organic phase and tetraethoxysilane as the inorganic network precursor. The consolidation process, used to reach a high degree of crosslinking between the two phases, was carried out with either conventional oven heating or microwave irradiation. High conversion degrees were obtained with both treatments even when microwave postcuring turned out to be much faster than conventional heating (5-10 s vs 40 min). Scratch-test and photooxidation investigations showed a significant improvement in scratch, yellowing, and photodegradation resistance for coated polycarbonate.

D. Fischer; D. Pospiech; U. Scheler; R. Navarro; M. Messori; P. Fabbri ( 2008 ) - Monitoring of the sol-gel synthesis of organic-inorganic hybrids by FTIR transmission, FTIR/ATR, NIR and Raman spectroscopy - MACROMOLECULAR SYMPOSIA - n. volume 265 - pp. da 134 a 143 ISSN: 1022-1360 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The sol-gel synthesis of org.-inorg. hybrids based on triethoxysilaneterminated poly(ethylene oxide) and tetraethylorthosilicate was monitored in-situ using three spectroscopic methods (FTIR/ATR, Raman, NIR). These spectroscopic methods allow in-situ monitoring of the evolution of hybrid materials starting from the modification of the polymer and the early steps of hydrolysis up to the network formation. By application of 29Si solid-state NMR spectroscopy the assignment and quantification of the Raman bands to different end groups and different crosslinking states was made. The sol-gel reaction was also followed by in-line NIR spectroscopy. A multivariate data anal. was accomplished to obtain a conversion-time curve. Furthermore, we investigated spin-coated films on wafers using FTIR transmission spectroscopy.

M. Messori; F. Bondioli; P. Fabbri; M.E. Darecchio ( 2008 ) - Nanoparticles for polymers reinforcement: a step towards the sustainable development of advanced materials [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

E. AMERIO; P. FABBRI; G. MALUCELLI; M. MESSORI; M. SANGERMANO; R. TAURINO ( 2008 ) - Scratch resistance of nano-silica reinforced acrylic coatings (Elsevier BV:PO Box 211, 1000 AE Amsterdam Netherlands:011 31 20 4853757, 011 31 20 4853642, 011 31 20 4853641, EMAIL: nlinfo-f@elsevier.nl, INTERNET: http://www.elsevier.nl, Fax: 011 31 20 4853598 ) - PROGRESS IN ORGANIC COATINGS - n. volume 62 - pp. da 129 a 133 ISSN: 0300-9440 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic–inorganic hybrid coatings were obtained by a dual-curing process combining the sol–gel reaction with the UV-induced polymerization technique by starting from bisphenol A ethoxylate (15 EO/phenol) dimethacrylate (BEMA, as organic network former), methacryloyloxypropyltrimethoxysilane (MEMO, as coupling agent) and tetraethoxysilane (TEOS, as inorganic silica network precursor). For comparison, TEOS was also substituted with preformed silica nanoparticles. Scratch test was carried out in order to study the scratch resistance of that silica reinforced acrylic resins. Excellent scratch resistant coatings were obtained by UV and sol–gel dual curing process. On the contrary, coatings with very poor scratch resistance were obtained by dispersing preformed nano-silica into the acrylic resin indicating the key role played by the morphology of the inorganic filler and its interaction with the organic matrix.

P. Fabbri; M. Messori; F. Pilati; L. Rovati ( 2008 ) - SENSORI DI pH IBRIDI ORGANICI-INORGANICI APPLICABILI A FIBRE OTTICHE ( 9° Congresso Nazionale AIMAT - Piano di Sorrento (Na) - 29 Giugno-2 Luglio 2008) ( - Atti del 9° Convegno Nazionale AIMAT ) (Edizioni Ziino Castellamare di Stabia ITA ) - pp. da 333 a 336 ISBN: 9788890094866 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

In questo lavoro è stata studiata la possibilità di preparare mediante tecnica sol-gel un sensore per misure di pH applicabile in punta di fibra ottica, che abbia come eventuali applicazioni l’utilizzo in pH-metria esofagea per monitorare i livelli di pH nell’esofago in pazienti affetti da reflusso gatroesofageo, il monitoraggio dei livelli di acidità o di basicità dei vapori industriali, di acque reflue, ecc. Si tratta di un sensore micro-invasivo che, grazie alla miniaturizzazione offerta dalla fibra ottica, consente di effettuare un monitoraggio continuativo del pH anche in situazioni complesse come la misura clinica a livello esofageo.

M. Sangermano; E. Borella; A. Priola; M. Messori; R. Taurino; P. Pötschke ( 2008 ) - Use of single-wall carbon nanotubes as reinforcing filler in UV curable epoxy system - MACROMOLECULAR MATERIALS AND ENGINEERING - n. volume 293 - pp. da 708 a 713 ISSN: 1438-7492 [Articolo in rivista (262) - Articolo su rivista]
Abstract

CNT were dispersed in an epoxy matrix and cured by means of UV light. An increase on elastic modulus and Tg values was measured by DMTA anal. and attributed to the constraint effect of CNT on polymer chain mobility. Excellent scratch resistant coatings characterized by high crit. load, small cracks and high recovery were obtained in the presence of a very low CNT content (0.025 wt.-%). TEM anal. showed some isolated CNT and some cluster agglomerations of size of about 250 nm. It was shown that it was possible to decrease the surface resistivity of the cured samples by three orders of magnitude in the presence of 0.1 wt.-% of SWCNT content.

Ezio Amerio; Marco Sangermano; Giovanna Colucci; Giulio Malucelli; Massimo Messori; Rosa Taurino; Paola Fabbri ( 2008 ) - UV Curing of Organic-Inorganic Hybrid Coatings Containing Polyhedral Oligomeric Silsesquioxane Blocks - MACROMOLECULAR MATERIALS AND ENGINEERING - n. volume 293 - pp. da 700 a 707 ISSN: 1438-7492 [Articolo in rivista (262) - Articolo su rivista]
Abstract

technique with a methacrylic oligomer and multifunctional methacrylic polyhedral oligomeric silsesquioxane blocks (POSS®). The results obtained from the polyhedral compounds were compared with those of a disordered framework obtained by the condensation of a silica precursor (MEMO). The inorganic domains generated during synthesis created constraints in movement of polymer segments, which reflected in an increase in Tg of the hybrid nanocomposite coatings. The films were transparent. The random structure obtained by the condensation of the MEMO showed a stronger effect on Tg than that observed by introducing POSS®. The effect of inorganic domains reflected on thermal stability, surface hardness and mechanical properties of the hybrid nano-composite coatings.

M. Messori; F. Pilati; M. Toselli; L. Mascia; C. Tonelli ( 2008 ) - Vinyl Ester Resins modified with Perfluoropolyethers - INTERNATIONAL JOURNAL OF SURFACE SCIENCE AND ENGINEERING - n. volume 2 - pp. da 310 a 324 ISSN: 1749-7868 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Hydroxy-terminated Perfluoropolyether (PFPE) was modified by copolymerisation with caprolactone or by addition of carboxylic or methacrylic terminal groups to increase the miscibility towards Vinyl Ester Resins (VERs). Fluorinated oligomers were employed as additives for a commercial VER. Depending on both molecular structure and curing conditions, different morphologies were obtained, which in turn influence the final properties of the cured resin. Generally, a significant increase in toughness was observed as is indicated by the stress intensity factor. A marked decrease in water diffusion coefficient was obtained, thanks to the hydrophobic character of PFPE.

M. MESSORI ( 2007 ) - Applicazioni di sistemi ibridi da sol–gel ( - Materiali polimerici ibridi e nanostrutturati ) (Pacini PISA ITA ) - pp. da 101 a 112 ISBN: 978 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Atti del XXVIII Convegno Scuola AIM Mario Farina su “Materiali polimerici ibridi e nanostrutturati” – 30 Aprile – 4 Maggio 2007, Gargnano (BS)

F. Pilati; M. Montecchi; P. Fabbri; A. Synytska; M. Messori; M. Toselli; K. Grundke; D. Pospiech ( 2007 ) - Design of surface properties of PET films: effect of fluorinated block copolymers - JOURNAL OF COLLOID AND INTERFACE SCIENCE - n. volume 315 (1) - pp. da 210 a 222 ISSN: 0021-9797 [Articolo in rivista (262) - Articolo su rivista]
Abstract

AbstractThis paper demonstrates that the addition of fluorinated block copolymers to PET solutions can be used to prepare PET films with controlled surface morphology, porosity and chemical composition, by exploiting the phenomenon known as breath figures (BF) formation during a spin-coating procedure. Surface features, such as number, depth and diameter of pores and chemical composition, can be tuned by varying the experimental conditions: relative humidity, solution composition and amount of the fluorinated block copolymer added to the PET solutions (in the range of 0.5–10 wt% with respect to PET). BF patterns are more evident at relatively high concentrations of PET (3 wt%) and content of fluorinated block copolymer (10 wt% with respect to PET) in the solution. According to the obtained results, the fluorinated block copolymer seems to play a role in different steps of the mechanism of BF formation. XPS measurements showed a surface composition much richer in fluorinated segments than expected from bulk composition. The combined surface roughness and surface segregation of fluorinated segments have only a limited effect on the macroscopic wettability of the surfaces.

PILATI F; M. MESSORI; FABBRI P; TOSELLI M ( 2007 ) - Engineering plastics ( - Raffinazione e petrolchimica ) (Treccani ROMA ITA ) - n. volume II - pp. da 885 a 916 ISBN: 978 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Volume II - Raffinazione e petrolchimica - Capitolo 12.6

PILATI F; M. MESSORI; FABBRI P; TOSELLI M ( 2007 ) - Engineering plastics ( - Refining and petrochemicals ) (Treccani ROMA ITA ) - n. volume II - pp. da 885 a 916 ISBN: 978 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Volume II - Refining and petrochemicals - Chapter 12.6

M. TOSELLI; M. MARINI; P. FABBRI; M. MESSORI; F. PILATI ( 2007 ) - Sol–gel derived hybrid coatings for the improvement of scratch resistance of polyethylene - JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY - n. volume 43 - pp. da 73 a 83 ISSN: 0928-0707 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic–inorganic hybrid materials were prepared through the sol–gel approach starting from tetraethoxysilane (TEOS), as silica precursor, and triethoxysilane terminated polymers; before gelling the solutions were applied to polyethylene (PE) films and slabs by spin-coating, without any previous surface pre-treatment of the substrate, and finally the coatings were thermally cured at 60 °C for 24 h. Among the various polymers used to prepare the coatings, only polyethylene-b-poly(ethylene glycol) copolymers gave good results in terms of adhesion to the PE substrates, and hybrid coatings with different organic–inorganic ratios were prepared. As suggested by visual inspection and SEM investigation, and confirmed by the critical loads derived from scratch tests, a good adhesion of the coating to the PE substrates was obtained, probably due to the presence of PE segments in the organic phase of the coating. Transparency as well as SEM and DSC data were in agreement with the formation of a nanostructured hybrid coating, with a high level of interpenetration between organic and inorganic domains. It was also observed that these hybrid coatings are able to improve significantly the scratch resistance and slightly increase the wettability with respect to uncoated PE. This approach to the surface-properties modification of PE appears as a simple and convenient method for the functionalization of PE substrates.

P. Fabbri; B. Singh; Y. Leterrier; J.A.E. Manson; M. Messori; F. Pilati ( 2006 ) - Cohesive and adhesive properties of polycaprolactone/silica hybrid coatings on poly(methyl methacrylate) substrates (Elsevier BV:PO Box 211, 1000 AE Amsterdam Netherlands:011 31 20 4853757, 011 31 20 4853642, 011 31 20 4853641, EMAIL: nlinfo-f@elsevier.nl, INTERNET: http://www.elsevier.nl, Fax: 011 31 20 4853598 ) - SURFACE & COATINGS TECHNOLOGY - n. volume 200 - pp. da 6706 a 6712 ISSN: 0257-8972 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic-inorganic hybrid materials were prepared using the sol-gel process in order to improve the scratch resistance of poly(methyl methacrylate) (PMMA) substrates. Sol-gel solutions based on tetraethoxysilane and alpha,omega-triethoxysilane terminated polycaprolactone with two different organic/inorganic weight ratios (5/5 and 7/3) were applied and cured on the substrate. The final coatings consisted of interconnected nanodomains of silica and polycaprolactone, which increased in size and resulted into microdomains when the content of organic phase increased. The surface energies of coated and uncoated PMMA, and the cohesive and adhesive properties of the hybrid coatings were examined using contact angle measurements, and fragmentation tests, respectively. The surface energy of the hybrid coatings and their work of adhesion to the PMMA substrate were found to be similar, with a higher polar contribution at increasing silica content. In contrast, the strain to failure, cohesive strength, toughness and adhesion to PMMA of the coating with a 5/5 organic/inorganic ratio were considerably higher, compared to the coating with a 7/3 organic/inorganic ratio. These results demonstrate that the adhesion strength is the result of a series of complex phenomena that probably involves diffusion of reactants in PMMA and their crosslinking, as suggested by electron energy loss spectroscopy analyses, other than effects deriving from residual stresses and from the morphology produced during the formation of the coating.

A. SACCANI; M. TOSELLI; M. MESSORI; P. FABBRI; F. PILATI ( 2006 ) - Electrical Behavior of PET Films Coated with Nanostructured Organic–Inorganic Hybrids - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 102 - pp. da 4870 a 4877 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Hybrid coatings, based on poly(ethylene oxide) (PEO) or polycaprolactone (PCL) and silica (SiO2), at different organic-inorganic compositions have been used to coat PET films employed in the electric industry to produce capacitors. The overall electrical behavior of the coated films has been investigated. The electrical strength of the coated films increases up to 10-15% of the uncoated ones regardless of polymer type (PEO/PCL) and amount of inorganic phase, as far as the thickness of the coating is below 5 μm. A systematic increase of surface electrical conductivity is found in all coated samples which however still behave as insulators. Permittivity and loss factor also increase particularly at low frequencies (< 10 Hz) on account of the presence of ions deriving from the sol-gel process and on the presence of interfacial polarization probably related to the coatings nanostructurated morphology which leads to phase separation.

P. Fabbri; M. Messori; M. Montecchi; S. Nannarone; L. Pasquali; F. Pilati; C. Tonelli; M. Toselli ( 2006 ) - Perfluoropolyether-based organic-inorganic hybrid coatings - POLYMER - n. volume 47 - pp. da 1055 a 1062 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Perfluoropolyether-based organic-inorganic hybrids were prepared by sol-gel process and applied as functional coatings onto glass substrates. Contact angle analysis and X-ray photoemission spectroscopy were carried out in order to characterize the surface of the prepared coatings. A strong hydrophobic and lipophobic character was observed for all tested compositions. The wettability behaviour was found to be dependent on both the coating technique and the reaction time of the sol-gel reaction. A strong surface segregation of perfluoropolyether segments was noted for all the prepared samples as evidenced by XPS analysis. On the basis of the obtained results, these materials could be used as functional coatings to prepare water and oil repellent glasses or other substrates.

F. Bondioli; V. Cannillo; E. Fabbri; M. Messori ( 2006 ) - Preparation and characterization of epoxy resins filled with submicron spherical zirconia particles - POLIMERY - n. volume 51 (11-12) - pp. da 794 a 798 ISSN: 0032-2725 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Submicron spherical zirconia particles were synthesized and used as a reinforcement for epoxy resins. In fact, recent developments indicate that a significant improvement in the thermoset polymer performance may be obtained by using submicron inorganic filler. In this paper, different composites with weight fraction of the filler in the range 1-5% were prepared and characterized in terms of mechanical properties. A numerical model suitable for the description of such materials was set up and employed to estimate the properties as functions of the reinforcement content.

P. FABBRI; M. MESSORI; M. MONTECCHI; F. PILATI; R. TAURINO; C. TONELLI; M. TOSELLI ( 2006 ) - Surface properties of fluorinated hybrid coatings - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 102 - pp. da 1483 a 1488 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A commercial perfluoropolyether containing alkoxysilane functionalities was employed to prepare organic-inorganic hybrid coatings by using the sol-gel process in the presence of tetraethoxysilane. Contact angle analysis revealed a strong hydrophobic and oleophobic character of the coatings almost independently from the molecular weight of the starting fluorinated oligomer. Surface tension values were in the range of 14-16 mN/m, suggesting a preferential segregation of fluorinated segments onto the surface of the coating. Atomic force microscopy showed the presence very smooth surfaces permitting to neglect the contribution of the surface roughness to wettability. Friction coefficient values were markedly lower with respect to the value of uncoated glass substrate.

N. Lotti; L. Finelli; M. Messori; A. Munari ( 2006 ) - Thiodiethylene glycol based polyesters: synthesis and thermal characterization - E-POLYMERS - n. volume 17 - pp. da 1 a 10 ISSN: 1618-7229 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(thiodiethylene terephthalate) (PSDET), poly(thiodiethylene adipate) (PSDEA), poly( diethylene terephthalate) (PDET) and poly(diethylene adipate) (PDEA) for comparison were synthsized and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermo gravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the sulfur-containing polyesters. At room temperature they appeared as semicrystalline materials, except PDEA, which was an oil; the effect of substitution of ether oxygen atoms with sulfur ones was a lowering in the T-g value, an increment of melting temperature and an increase of crystallization rate. The results were explained as due to the presence of flexible C-S-C bonds in the polymeric chain.

F. BONDIOLI; V. CANNILLO; E. FABBRI; M. MESSORI ( 2005 ) - Epoxy-silica nanocomposites: Preparation, experimental characterization and modeling - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 97 - pp. da 2382 a 2386 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Silica nanoparticles having different sizes were obtained by the sol-gel process and characterized. The prepared nanoparticles were subsequently used as reinforcing fillers to prepare epoxy-based composites with a silica content ranging from I to 5 wt %. SEM analysis and tensile tests carried out on the silica-epoxy nanocomposites indicated the absence of particle aggregation and a reinforcing effect in terms of increased elastic modulus. Mechanical properties were also modeled by using a finite element code able to construct a numerical model from a microstructural image of the material. A more reliable model was prepared by considering the presence of an interphase layer surrounding the particles with intermediate elastic properties between the epoxy and the inclusions and a characteristic size proportional to the particle radius.

LEONELLI C.; M. MESSORI; PILATI F.; VERONESI P. ( 2005 ) - Non-Conventional Curing of Organic-Inorganic Hybrids (Huethig & Wepf Verlag:Auf dem Wolf 4, CH 4018 Basel Switzerland:011 41 61 3179410, Fax: 011 41 61 3179411 ) - MACROMOLECULAR SYMPOSIA - n. volume 228 - pp. da 229 a 236 ISSN: 1022-1360 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Infrared and microwave curing of organic-inorganic hybrid materials was studied, in order to achieve the maximum conversion without detrimental effects due to the overheating or to the long-time permanence at high temperature. Partially cured poly(ethylene oxide)/silica hybrids were prepared by hydrolysis and subsequent condensation of precursors for 30 minutes isothermal heat treatment at 70°C. The conversion after the preliminary treatment is still low and requires an additional heating to complete the reaction. Three different thermal treatments were investigated: conventional heating, infrared heating and microwave heating. DSC characterisation of the obtained samples evidenced a drastic reduction of the treatment time when microwaves were used, requiring only a few seconds, compared to the hours-lasting conventional treatments.

M. Messori; M. Toselli; F. Pilati; P. Fabbri; L. Pasquali; M. Montecchi; S. Nannarone; C. Tonelli ( 2005 ) - Perfluoropolyether-based organic-inorganic hybrid coatings: Preparation and surface characterisation - SURFACE COATINGS INTERNATIONAL. PART B, COATINGS TRANSACTIONS - n. volume 88 - pp. da 243 a 249 ISSN: 1476-4865 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Hydrophobic-oleophobic coatings were prepared by using the sol-gel process with organic-inorganic hybrids based on perfluoropolyether-polycaprolactone (PFPE-PCL) copolymers. Hybrid coatings were prepared by changing the organic-inorganic ratio, the PFPE/PCL ratio in the copolymer, and the reaction conditions. A complete surface characterisation was carried out by contact angle analysis and x-ray photoemission spectroscopy (XPS). In all cases the wettability of the coatings was found to be very low. Surface composition analysis showed that the surface segregation of the fluorinated PFPE segments was always high enough to give a very high hydrophobic character to the coating surface.

M. MESSORI; TOSELLI M.; PILATI F.; FABBRI P.; PASQUALI L.; MONTECCHI M.; NANNARONE S.; TONELLI C. ( 2005 ) - Perfluoropolyether-based Organic-Inorganic Hybrid Coatings: Preparation and Surface Characterization - PAINT & COATINGS INDUSTRY - n. volume 21 - pp. da 76 a 85 ISSN: 0884-3848 [Articolo in rivista (262) - Articolo su rivista]
Abstract

not available

M. MESSORI; M. TOSELLI; F. PILATI; E. FABBRI; P. FABBRI; L. PASQUALI; M. MONTECCHI; S. NANNARONE; C. TONELLI ( 2005 ) - Perfluoropolyether-silica hybrids: preparation and surface characterization - JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY - n. volume 34 - pp. da 155 a 163 ISSN: 0928-0707 [Articolo in rivista (262) - Articolo su rivista]
Abstract

α,ω-Triethoxysilane terminated perfluoropolyether-polycaprolactone block copolymers, TXCL(x)Si, were synthesised, characterised and subsequently reacted with tetraethoxysilane to prepare transparent organicinorganic hybrid materials by using the sol–gel process. Surface characterization was carried out through contact angle measurements. All the materials investigated (independently on both the reaction time of the sol–gel reaction before coating application and the bulk organic-inorganic ratio) showed a strong hydrophobic character when compared with non-fluorinated and fully inorganic control materials. The highest water contact angles were obtained when TXCL(x)Si oligomer used for the preparation of the hybrid contained short hydrogenated polycaprolactone segments. In all cases, the surface tension values indicated that the very surface at the air-coating interface showed almost completely perfluoropolyether segments.

R. Bongiovanni; G. Malucelli; M. Messori; F. Pilati; A. Priola; C. Tonelli; M. Toselli ( 2005 ) - Poly(caprolactone-co-lactide)/perfluoropolyether block copolymers: Synthesis, thermal, and surface characterization - JOURNAL OF POLYMER SCIENCE. PART A, POLYMER CHEMISTRY - n. volume 43 - pp. da 3588 a 3599 ISSN: 0887-624X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly[(caprolactone-co-lactide)-b-perfluoropolyether-b-(caprolactone-co-lactide)] copolymers (TXCLLA) were prepared by ring-opening polymerization Of D,L-dilactide (LA2) and caprolactone (CL) in the presence of alpha,omega-hydroxy terminated perfluoropolyether (Fomblin Z-DOL TX) as macroinitiator and tin(H) 2-ethylexanoate as catalyst. H-1 NMR analysis showed that LA2 is initially incorporated into the copolymer preferentially with respect to CL. A blocky structure of the polyester segment was also indicated by the sequence distribution analysis of the monomeric units. Differential scanning calorimetry analysis showed the compatibility between poly(lactide) (PLA) and poly(caprolactone) (PCL) blocks inside the amorphous phase with glass-transition temperature values increasing from -60 to -15 degrees C by increasing the PLA content. Copolymers with high average length of CL blocks were semi-crystalline with a melting temperature ranging from +35 to +47 degrees C. Surface analysis showed a high surface activity of TXCLLA copolymers with values of surface tension independent from the PLA/PCL content and very close to those of pure TX.

L. Mascia; VSY Ng; RH Heath; M. Messori ( 2005 ) - Silane functionalization of perfluoroether oligomers for reaction management and morphology control of two-phase epoxy networks - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 98 - pp. da 1036 a 1049 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Mixtures of an epoxy resin, hardener, and acid functionalized perfluoroether oligomers will readily undergo phase separation during curing. However, the conditions to bring about the growth of nuclei into microscopic particles have hitherto been found only for systems cured with anhydrides. In the present study perfluoroether oligomers were functionalized by established procedures to introduce both carboxylic acid groups and alkoxysilane groups in sites within the chain extended segments. The presence of alkoxysilane groups together with the prereaction step with an excess epoxy resin, prior to the addition of the aromatic amine hardener, induced phase separation by a nucleation-and-growth mechanism. The dual functionality in the perfluoroether oligomer was even more beneficial when the alkoxysilane groups were hydrolyzed prior to the addition of the amine hardener. Under such circumstances the precipitation of the perfluoroether oligomer occurred quantitatively, as indicated by the complete absence of any plasticization effects in the epoxy matrix. From electron microscopy examinations, thermal analysis, and measurements of mechanical properties it was possible to deduce a plausible mechanism for the formation of the typical core-shell aggregates within the precipitated particles for these systems, which could also be applied to other systems, such as those using carboxylic-acid-terminated butadiene acrylonitrile oligomers.

FINELLI L.; LORENZETTI C.; M. MESSORI; SISTI L.; VANNINI M. ( 2004 ) - Comparison Between Titanium Tetrabutoxide and a New Commercial Titanium Dioxide Based Catalyst Used for the Synthesis of Poly(Ethylene Terephthalate) (John Wiley & Sons Incorporated:Customer Service, 111 River Street:Hoboken, NJ 07030:(800)225-5945, (201)748-6000, EMAIL: societyinfo@wiley.com, INTERNET: http://www.wiley.com, Fax: (212)748-6551 ) - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 92 - pp. da 1887 a 1892 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Titanium-based catalysts for poly(alkylene terephthalate) synthesis have been known for many years. Up to now, organotitanate compounds are used as catalysts on an industrial scale only for the synthesis of poly(butylenes terephthalate) (PBT), poly(trimethylene terephthalate) (PTT), and related copolyesters; for poly(ethylene terephthalate) (PET), synthesis antimony-based catalysts are preferred. In fact, in this case, titanium is known to cause undesirable discoloration. In this article, a study of PET synthesis using different concentrations of a new titanium dioxide based catalyst (C-94), commercially available from Acordis Industrial Fibers GmbH, is carried out and compared with the results obtained with titanium tetrabutoxide (TBT) catalyst in the same experimental conditions. The solid-state properties and composition of C-94 was investigated by thermogravimetric analysis (TGA) coupled with mass spectroscopy and by X-ray powder diffraction (XRD). A characterization of the polymers prepared with C-94 and TBT is also described. The results have shown that the use of C-94 leads to more hydrolytically stable polymers, whereas no evidence of difference in the catalytic activity, carboxyl end-groups concentration, diethylene glycol content, and thermal properties were revealed.

M. MESSORI; A. TOSELLI; F. PILATI; E. FABBRI; P. FABBRI; L. PASQUALI; S. NANNARONE ( 2004 ) - Prevention of plasticizer leaching from PVC medical devices by using organic-inorganic hybrid coatings - POLYMER - n. volume 45 - pp. da 805 a 813 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

α,ω-triethoxysilane terminated poly(ethylene oxide) (PEO-Si) was prepared and used to produce organic/inorganic hybrids by the sol–gel approach. These hybrids were used as coatings for flexible PVC tubes in order to reduce the plasticizer leaching from PVC medical devices. Extraction tests carried out with hexane indicated that all coating composition investigated are able to strongly reduce (about one order of magnitude) the leaching of di-ethylhexyl phthalate in hexane. The best results were obtained by an accurate balance of organic and inorganic phases content. XPS analysis showed a preferential segregation of silica onto the outer surface suggesting that a high inorganic content at the coating–extraction medium interface was present.

E. FABBRI; P. FABBRI; M. MESSORI; F. PILATI; C. TONELLI; M. TOSELLI ( 2004 ) - Surface modification of unsaturated polyester resins with perfluoropolyethers - POLIMERY - n. volume 49 - pp. da 785 a 789 ISSN: 0032-2725 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Fluorine-modified unsaturated polyester resins (FUPR) were prepared by using polycaprolactone-perfluoropolyether-polycaprolactone triblock copolymers having hydroxyl or methacrylate end-groups. Despite the immiscibility of the perfluoropolyether segment, all the modified resins were fully transparent after curing thanks to the compatibilization effect of the polycaprolactone segments. Contact angle measurements showed a very low water wettability for all investigated resin compositions. Also in the case of system with the lower bulk copolymer concentration (less than 0.3 phr) contact angles were higher than 94°. It has been demonstrated that the presence of methacrylate end-groups tends to hinder the surface segregation of the fluorinated additive.

M. MESSORI; M. TOSELLI; F. PILATI; E. FABBRI; P. FABBRI; S. BUSOLI; L. PASQUALI; S. NANNARONE ( 2003 ) - Flame Retarding Poly(Methyl Methacrylate) with Nanostructured Organic-Inorganic Hybrids Coatings (Elsevier Science Limited:Oxford Fulfillment Center, PO Box 800, Kidlington Oxford OX5 1DX United Kingdom:011 44 1865 843000, 011 44 1865 843699, EMAIL: asianfo@elsevier.com, tcb@elsevier.co.UK, INTERNET: http://www.elsevier.com, http://www.elsevier.com/locate/shpsa/, Fax: 011 44 1865 843010 ) - POLYMER - n. volume 44 - pp. da 4463 a 4470 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic–inorganic hybrid materials were prepared starting from tetraethoxysilane and α- or α,ω-triethoxysilane terminated poly(ε-caprolactone) (PCL–Si) using the sol–gel process. In all cases the formation of nanocomposites with a high level of interpenetration between organic and inorganic phases was noted. Poly(methyl methacrylate) slabs were dip-coated with PCL–Si/silica hybrids and a very strong increase of the flame resistance (also after UV irradiation) was noted for all coating compositions without marked differences with respect to hybrid compositions. This behavior was attributed to a preferential segregation of silica onto the outer surface, as evidenced by XPS analysis.

M. Colonna; TE Banach; C. Berti; M. Fiorini; E. Marianucci; M. Messori; F. Pilati; M. Toselli ( 2003 ) - New catalysts for poly(butylene terephthalate) synthesis. Part 3: Effect of phosphate co-catalysts - POLYMER - n. volume 44 - pp. da 4773 a 4779 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

An exhaustive study of the co-catalytic activity of phosphates on titanium and titanium/hafnium based catalytic systems in poly(butylene terephthalate) synthesis was conducted in order to investigate any improvement in the process and/or in the properties of the final polymer with respect to the industrially used titanium based catalyst. Small scale polymerisation and subsequent scale up in higher capacity reactors showed a strong co-catalytic effect of phosphates. A screening on model compounds showed NaH2PO4 to be the most active co-catalyst. The co-catalysts had a stronger effect on titanium with respect to hafnium. Decreases in polymerisation time and tetrahydrofuran formation were observed, which in turn can improve the productivity of the whole process. Moreover, the use of phosphate improved the thermal stability of the final polymers. (C) 2003 Elsevier Science Ltd. All rights reserved.

M. Messori; M. Toselli; F. Pilati; E. Fabbri; P. Fabbri; S. Busoli ( 2003 ) - Poly(caprolactone)/silica organic-inorganic hybrids as protective coatings for poly(methyl methacrylate) substrates - SURFACE COATINGS INTERNATIONAL. PART B, COATINGS TRANSACTIONS - n. volume 86 - pp. da 181 a 186 ISSN: 1476-4865 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Organic-inorganic hybrid materials (also known as ceramers or phase-interconnected nanocomposites) were prepared starting with tetraethoxysilane and α,ω-triethoxysilane-terminated poly(ε-caprolactone) (PCL-Si) using the sol-gel process. In all cases the formation of nanocomposites with a high level of interpenetration between PCL and SiO2 phases was noted. Poly(methyl methacrylate) (PMMA) slabs were dip-coated with PCL-Si/silica hybrids and a preferential segregation of silica on to the outer surface was found, together with a PCL-rich coating PMMA interface. In all cases, a marked reduction in both the average roughness and the apparent friction coefficient was noted with respect to the uncoated PMMA. All the PCL-Si/SiO2-coated samples showed a significant increase in flame resistance before and after UV irradiation, while improvements in the anti-scratch properties were noted only in the case of the PMMA coated with silica-rich ceramers.

M. Toselli; JA Gardella; M. Messori; AM Hawkridge; F. Pilati; C. Tonelli ( 2003 ) - Surface chemical analysis of poly(epsilon-caprolactone)-perfluoropolyether-poly(epsilon-caprolactone) triblock copolymers by X-ray photoelectron spectroscopy - POLYMER INTERNATIONAL - n. volume 52 - pp. da 1262 a 1274 ISSN: 0959-8103 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The air-side surface composition of a series of poly(e-caprolactone)-perfluoropolyether-poly(epsilon-caprolactone) triblock copolymers with different compositions and block lengths have been studied by angle-dependent X-ray photoelectron spectroscopy (XPS). The weight percentage of the perfluoropolyether (PFPE) and polycaprolactone (PCL) blocks, and ethylene oxide linker (RH) has been calculated in different ways: from C1s, O1s and F1s photoemission peaks and by line fitting of the C1s and O1s envelopes. The atomic sensitivity factors and the parameters used to fit the peak envelopes have been experimentally determined using some reference materials. A critical discussion of the different methods used in the surface characterization and the degradation of PFPE segments, induced by irradiation beam, have been also reported. A large excess of PFPE with respect to the bulk composition was observed in all samples, and the angular dependence of the XPS signal demonstrated that the content of the fluorinated block segment increased by decreasing the sampling depth. The PFPE surface concentration was also decreased by increasing the PCL/PFPE ratio, but the surfaces of the samples were still dominated by PFPE segments for copolymers with a bulk PFPE composition lower than 10%. Moreover, copolymers with similar PCL/PFPE bulk ratios but with different PFPE block lengths, showed similar PFPE surface composition when the number-average molecular weight (M.) was 2000 and 3200 g mol(-1), while that observed for copolymers containing PFPE block with M. 900 g mol(-1) was lower.

M. Messori; M. Toselli; F. Pilati; P. Fabbri; C. Tonelli ( 2002 ) - Poly(epsilon-caprolactone)-poly(fluoroalkylene oxide)-poly(epsilon-caprolactone) block copolymers as surface modifiers of poly(vinyl chloride) - SURFACE COATINGS INTERNATIONAL. PART B, COATINGS TRANSACTIONS - n. volume 85 - pp. da 197 a 201 ISSN: 1476-4865 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Blends of poly(epsilon-caprolactone)-poly(fluoroalkylene oxide)-poly(epsilon-caprolactone) (PCL-PFPE-PCL) triblock copolymers (with different length of PFPE and PCL segments) and poly(vinyl chloride) (PVC) were prepared by casting from tetrahydrofuran solution. DSC analysis revealed a complex morphology deriving from miscibility between PCL and PVC segments. XPS analysis showed strong surface enrichment of PFPE segments for all films prepared. Treatment with a PFPE selective solvent showed that the fraction of PCL-PFPE-PCL removed from surface decreased with increasing length of PCL blocks, indicating an anchorage effect by PCL segments with respect to PVC matrix.

M. Messori; M. Toselli; F. Pilati; L. Mascia; C. Tonelli ( 2002 ) - Synthesis and characterisation of silica hybrids based on poly (epsilon-caprolactone-b-perfluoropolyether-b-epsilon-caprolactone) - EUROPEAN POLYMER JOURNAL - n. volume 38 (6) - pp. da 1129 a 1136 ISSN: 0014-3057 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(epsilon-caprolactone-b-perfluoropolyether-b-epsilon-caprolactone) (PCL-PFPE-PCL) triblock copolymers having hydroxy end groups were readily functionalised with triethoxysilane end groups by reactions with 3-isocyanatopropyltriethoxysilane. Organic-inorganic hybrids were prepared by using the sol-gel process in the presence of tetraethoxysilane and hydroxy or triethoxysilane terminated PCL-PFPE-PCL. Fully transparent hybrid materials with high content of organic matter were obtained only in the case of alkoxysilane functionalised copolymers. For such systems the PCL-PFPE-PCL copolymer was so intimately mixed with the inorganic network to prevent crystallisation of the PCL segments, The progress of the sol-gel reaction was limited by the early vetrification of the reactive system, while the interpenetration of the organic phase was enhanced by curing the samples at 100 degreesC. (C) 2002 Elsevier Science Ltd. All rights reserved.

F. Pilati; T.E. Banach; C. Berti; M. Colonna; M. Fiorini; M. Messori; E. Marianucci; M. Toselli ( 2001 ) - New catalysts for poly(butylene terephthalate) synthesis 1. Titanium-lanthanides and titanium-hafnium systems - POLYMER - n. volume 42 - pp. da 7511 a 7516 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A complete study of the catalytic activity of lanthanide-, and hafnium acetylacetonate catalysts in PET synthesis was conducted in order to investigate any improvement in the process and/or in the properties of the final polymer with respect to the industrially used titanium tetrabutoxide (TBT) catalyst. Small scale polymerization and subsequent scale up in higher capacity reactors showed that TBT-Hf(acac)4 and TBT-La(acac)3 mixed catalysts were more active with respect to TBT as single catalyst. Decreases in polymerization time and THF formation were also observed, which in turn can improve the productivity of the whole process. Furthermore, for similar values of molecular weight, a lower melt viscosity (and thus better processability and crystallizability) was obtained by using mixed catalysts, presumably due to weaker interactions of the polymer terminal groups to lanthanum and hafnium metals with respect to titanium.

M. Messori; M. Toselli; F. Pilati; P. Fabbri ( 2001 ) - Poly(e- caprolactone)-poly(fluoroalkylene oxide)-poly(e-caprolactone) block copolymers as surface modifiers of poly(vinyl chloride) ( Fluorine in Coatings IV - Brussels - Belgium - 5-7 marzo 2001) ( - Conference Papers of Fluorine in Coatings IV ) (The Paint Research Association Teddington GBR ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Blends of poly(caprolactone-b-perfluoropolyether-b-caprolactone) (PCL-PFPE-PCL) triblock copolymers (with different length of PFPE and PCL segments) and poly(vinyl chloride) (PVC) were prepared by casting from tetrahydrofuran solution. DSC analysis revealed a complex morphology deriving from miscibility between PCL and PVC segments. XPS analysis showed strong surface enrichment of PFPE segments for all films prepared. Treatment with PFPE selective solvent showed that the fraction of PCL-PFPE-PCL removed from surface decreased with increasing length of PCL blocks, indicating an anchorage effect by PCL segments with respect to PVC matrix.

F. Pilati; M. Messori; M. Toselli; R. Bongiovanni; G. Malucelli; A. Priola; C. Tonelli ( 2001 ) - Poly(epsilon-caprolactone)-poly(fluoroalkylene oxide)-poly(epsilon-caprolactone) block copolymers. 2. Thermal and surface properties - POLYMER - n. volume 42 - pp. da 1771 a 1779 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The thermal and the surface properties of PCL-PEPE-PCL block copolymers having different PCL and PFPE block lengths were investigated by DSC, contact angles and XPS measurements. DSC analysis reveals for all the copolymers the presence of different amorphous phases; the phase located at low temperature was attributed to the fluorinated moiety. Tm values also demonstrated that PCL crystallizes from a pure phase. XPS measurements showed a strong surface enrichment in PFPE with respect to the bulk. Contact angle values showed a hydrophobic character of the film surface even if the trend was found not depending on the fluorine concentration as detected by XPS: this behavior may be explained by the presence of very flexible blocks, providing a highly dynamic surface. These structures can be potentially used as additives for the formation of polymers having 'smart surfaces' with selective adhesive properties.

M. Messori; M. Toselli; F. Pilati; C. Tonelli ( 2001 ) - Unsaturated polyester resins modified with poly(epsilon-caprolactone)-perfluoropolyethers block copolymers - POLYMER - n. volume 42 - pp. da 9877 a 9885 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(epsilon -caprolactone)-perfluoropolyether-poly(epsilon -caprolactone) block copolymers (TXCL) synthesised from Fomblin Z-DOL TX (TX) have been mixed with conventional unsaturated polyester resins (UPR) to prepare fluorine modified UPR (FUPR). A preliminary investigation on the compatibility of uncured FUPR systems has shown that the presence of PCL blocks leads to an enhancement of compatibility with respect to pure perfluoropolyether macromers. The compatibility tends to decrease by increasing the TXCL concentration in the mixture depending on both molecular weight and TX/PCL ratio. Also the morphology of FUPR after curing was strongly affected by the rate of curing and by a critical balancing of TX/PCL ratio and molecular weight of TXCL copolymers. Both transparent and opaque FUPR were obtained for the same composition at different curing rates; high curing rates (i.e. high concentration of initiator/activator) favoured the formation of transparent FUPR through a kinetic control of phase separation. Scanning electron microscopy (SEM) analysis was in good agreement with the macroscopic results obtained by visual inspection. XPS analysis showed a very strong surface enrichment in fluorinated segments, which increases by increasing the TX/PCL ratio. Mechanical tests showed a slight plasticization effect (compared to UPR control) together with a very strong improvement in the absorbed energy at break EB showing the best toughening effect for TXCL with intermediate TX/PCL ratio. Finally, a minimisation of the water diffusion coefficient value (five times lower than UPR control) was noted for UPR modified with TXCL having intermediate PCL segment length. (C) 2001 Elsevier Science Ltd. All rights reserved.

R. Bongiovanni; G. Malucelli; M. Messori; F. Pilati; A. Priola; C. Tonelli; M. Toselli ( 2000 ) - Acrylic polyester resins containing perfluoropolyethers structures: Synthesis, characterization, and photopolymerization - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 75 - pp. da 651 a 659 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(epsilon-caprolactone-b-perfluoropolyether-b-epsilon caprolactone) (PCL-PFPE-PCL) block copolymers having different PCL block lengths and end-capped with methacrylate groups were prepared and characterized. Spectroscopic analyses confirmed the expected molecular structure of the products. After UV curing, the films revealed the presence of two amorphous phases, corresponding to fluorinated and hydrogenated moieties, respectively. The material containing long PCL blocks showed also a crystalline phase. Surface properties of the UV-cured films were evaluated: The surfaces have a very high hydrophobic character in spite of the presence of many polar OH groups present in the polymeric network and a high hysteresis in wetting. An enrichment of fluorine at the air-side surface was shown by contact-angle measurements, except when long PCL sequences are present. The theta(adv) angles decreased by increasing the content of PCL, that is, by decreasing the content of fluorine.

F. PILATI; M. MESSORI; P. FABBRI; M. TOSELLI ( 2000 ) - Modifica del PVC per applicazioni biomedicali - BIOMATERIALI - n. volume 2 - pp. da 29 a 30 ISSN: 1124-3554 [Articolo in rivista (262) - Articolo su rivista]
Abstract

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F. Pilati; M. Toselli; M. Messori; A. Priola; R. Bongiovanni; G. Malucelli; C. Tonelli ( 1999 ) - Poly(epsilon-caprolactone)-poly(fluoroalkylene oxide)-poly(epsilon-caprolactone) block copolymers. 1. Synthesis and molecular characterization - MACROMOLECULES - n. volume 32 - pp. da 6969 a 6976 ISSN: 0024-9297 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Hydroxyl-terminated telechelic poly(fluoroalkylene oxide)s, (PFPE)s, with molecular weights ranging from 1100 to 3400 were employed as transfer agents for the ring-opening polymerization of epsilon-caprolactone (CL) in the presence of various catalysts/initiators. The highest conversion rate of CL was observed using Ti(OBu)(4) and Bu2SnO as catalysts/initiators. The polymerization of CL started only from the hydroxyl groups of PFPE, leading to the formation of ABA triblock copolymers without formation of homopolymer poly(epsilon-caprolactone) (PCL). The rate of insertion of the first unit of CL is much faster than the insertion of the other CL units, and the average molecular weight of the ABA copolymers was that expected by the CL/PFPE ratio. The polymerization rate of CL in the presence of PFPE using aluminum alkoxides as initiator was very slow, contrary to what is known about the homopolymerization of CL.

PILATI F.; TOSELLI M.; M. MESSORI ( 1999 ) - Polyester design considerations ( - Waterborne and Solvent Based Saturated Polyesters and their End User Applications ) (John Wiley and Sons LONDON GBR ) - pp. da 75 a 173 ISBN: 471 978884 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

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F. Pilati; M. Toselli; M. Messori ( 1999 ) - Principles of step polymerization ( - Waterborne and Solvent Based Saturated Polyesters and their End User Applications ) (John Wiley and Sons London GBR ) - pp. da 1 a 71 ISBN: 0471978884; 9780471978886 | 9780471978886 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

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F. Pilati; M. Toselli; M. Messori; U. Credali; C. Tonelli; C. Berti ( 1998 ) - Unsaturated polyester resins modified with perfluoropolyethers - JOURNAL OF APPLIED POLYMER SCIENCE - n. volume 67 - pp. da 1679 a 1691 ISSN: 0021-8995 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Telechelic macromers based on hydroxyterminated perfluoropolyethers (HO-R-H-PFPE-R-H-OH) with different molecular weights were used for the preparation of fluorine-containing unsaturated polyester resins (FUPR). The products resulting from the reaction of the monomers usually employed for the preparation of unsaturated polyesters with HO-R-H-PFPE-R-H-OH were in any case milky liquids. The degree of reaction of the hydroxyl terminal groups of HO-R-H-PFPE-R-H-OH was monitored by H-1-NMR analysis on the fractions collected after sedimentation experiments; amount and composition of the sediment and sedimentation rate were found dependent on both the molecular weight of fluorinated macromer and the method used for polyesterification. The molecular weight of HO-R-H-PFPE-R-H-OH and the reaction conditions had also a strong influence on the final morphology of crosslinked polymers. A very poor interphase adhesion was observed when unreacted HO-R-H-PFPE-R-H-OH was blended with the unsaturated polyester. On the contrary, when the fluorinated macromer was allowed to react during polyesterification, the adhesion of the fluorine-rich dispersed phase to the unsaturated polyester matrix was good for low molecular weight HO-R-H-PFPE-R-H-OH and when the fluorinated prepolymer had been modified by a previous reaction with chlorendic anhydride, but it was poor, as for unreacted macromers, for high molecular weight HO-R-H-PFPE-R-H-OHs. FUPRs prepared using a low molecular weight HO-R-H-PFPE-R-H-OH exhibited a significant improvement of the flexural strength even at very low level of addition (3% by wt).

F. Pilati; M. Toselli; M. Messori; C. Manzoni; A. Turturro; E.G. Gattiglia ( 1997 ) - On specific factors affecting the crystallization of PET: role of carboxyl terminal groups and residual catalysts on the crystallization rate - POLYMER - n. volume 38 - pp. da 4469 a 4476 ISSN: 0032-3861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The non-isothermal crystallization rate of poly(ethylene terephthalate) (PET) has been studied in differential scanning calorimetry experiments, by cooling from the molten state of samples of various molecular weights, prepared using various catalysts (mainly Ti(OBu)4). The crystallization temperature, Tc, was obviously influenced by the molecular weight, but also by the carboxyl group content, by the type of residual catalyst, by dissolution-reprecipitation treatments and by re-melting phenomena. The observed effects were interpreted assuming that interactions of terminal groups of the PET chains (mutual or with residual catalyst) led to an apparent increase in molecular weight, which in turn determined a decrease in the chain mobility and was responsible for a decrease in the rate of crystallization. Thus, a higher concentration of carboxyl terminal groups as well as interactions of PET terminal groups with the catalyst decreased Tc. Any factor which was able to destroy these interactions (treatments of dissolution-reprecipitation, phosphorous derivatives, aging) led to an increase of the overall crystallization rate.

G.L. CASTIGLIONI; A. GUERCIO; M. MESSORI; A. VACCARI ( 1995 ) - VAPOR-PHASE HYDROGENATION OF MALEIC-ANHYDRIDE TO GAMMA-BUTYROLACTONE. 3. REACTION PATHWAY AND NEW CATALYST COMPOSITIONS - ERDÖL UND KOHLE, ERDGAS, PETROCHEMIE VEREINIGT MIT BRENNSTOFF-CHEMIE - n. volume 48 - pp. da 174 a 178 ISSN: 0367-0716 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The reactivities of the main products observed in the vapour phase hydrogenation of maleic anhydride (MA) were investigated separately, using a multicomponent catalyst (Cu/Zn/Mg/Cr=40:5:5:50, atomic ratio %), obtained by reduction of a non-stoichiometric spinel-type precursor. Tetrahydrofuran (THF) reacted only at high temperature forming small amounts of ethanol (EtOH), while gamma-butyrolactone (GBL) gave rise, with high conversion, to overhydrogenation [to butyric acid (BuA) or n-butanol (BuOH)] and/or hydrogenolysis [mainly to EtOH. Furthermore, the formation in the catalytic tests with BuA and BuOH of n-butanal (notwithstanding the high H-2/organic ratio), suggested it as the main intermediate in the hydrogenolysis reaction. Therefore, a new reaction scheme is proposed, evidencing the key role of GBL as the ''intersection'' of two possible reaction pathways, giving rise to THF or unwanted and low-cost by-products. Because of the increasing restrictions on the use of Cr-containing catalysts, the research was extended to include an investigation of the reactivity of Al-containing catalysts, also prepared by reduction of spinel-type precursors. These catalysts, in particular those with low copper contents, gave rise to high productions of GEL, favouring also the formation of THF and reducing the amounts of unwanted and low-cost by-products. It was shown that a Cu/Zn/Al=25:25:50 (atomic ratio %) composition may represent a useful compromise, allowing good yields in GBL to be obtained at lower reaction temperatures.

M. MESSORI; A. VACCARI ( 1994 ) - REACTION PATHWAY IN VAPOR-PHASE HYDROGENATION OF MALEIC-ANHYDRIDE AND ITS ESTERS TO GAMMA-BUTYROLACTONE - JOURNAL OF CATALYSIS - n. volume 150 - pp. da 177 a 185 ISSN: 0021-9517 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The catalytic reactivity of maleic anhydride (MA), succinic anhydride (SA) and their dimethyl esters (dimethyl maleate and dimethyl succinate) in the vapour phase hydrogenation to gamma-butyrolacetone (GBL) was investigated. In order to obtain general data, both a multicomponent catalyst (CAT 1: Cu/Zn/Mg/Cr 40:5:5:50, atomic ratio %), obtained by reduction of a nonstoichiometric spinel-type precursor, and a commercial catalyst (CAT 2: Cu/Mn/Ba/Cr = 44:8:1:47, atomic ratio %) were used. The MA/GBL solution exhibited the highest GBL production, while the SA/GBL solution was converted only partially due to a competitive adsorption of GBL on the active sites, as evidenced by the similar reactivities observed with pure anhydrides. The best carbon balances were observed with the esters, probably the result of lowest light hydrocarbon synthesis and tar formation. With all the feedstocks, the activity of CAT 2 is higher than that of CAT 1, which, however, gives the best yield in GBL due its lower activity in the overhydrogenation and hydrogenolysis reaction. It was found that n-butanol (BuOH) and butyric acid (BuA) derived mainly from GBL. On this basis, the reactivities of the main products observed were investigated separately, confirming the stability of tetrahydrofuran (THF), which reacted only at high temperature with low conversions to ethanol. On the other hand, GBL gave rise to overhydrogenation and/or hydrogenolysis, with high conversion (mainly with CAT 2), confirming its key role in both reactions. Furthermore, the formation in the catalytic tests with BuA and BuOH of n-butanal, notwithstanding the high H-2/organic ratio, implies that it is the main intermediate in the hydrogenolysis reactions. A new reaction scheme is proposed, pointing out the key role of GBL as the ''intersection'' of two possible reaction pathways, giving rise to THF or overhydrogenation and hydrogenolysis products, respectively.

G. GOLINELLI; F. TRIFIRO; M. BAERNS; F. MAJUNKE; M. MESSORI; B. GRZYBOWSKA; J. CZEKAJ; B. MAJKA; C. DIAS; M. PORTELA ( 1994 ) - SELECTIVE OXIDATION OF O-XYLENE TO PHTHALIC-ANHYDRIDE OVER THE EUROCAT V2O5/TIO2 CATALYSTS - CATALYSIS TODAY - n. volume 20 - pp. da 153 a 163 ISSN: 0920-5861 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The selective oxidation of o-xylene to phthalic anhydride has been studied in four laboratories, using catalysts EL10V1 and EL10V8; conversions and product yields as a function of time-on-stream are reported. The results obtained are in generally good agreement: for both catalysts, phthalic anhydride yields at 40% conversion are ca. 20%, rising to 63-70% at 100% conversion. Increasing the vanadium content from 1 to 8% has little effect and may even result in a slightly worse performance. Differences in the temperatures required to attain a fixed conversion may reflect differences in reactor design, especially with regard to heat exchange efficiency.

G.L. CASTIGLIONI; C. FUMAGALLI; A. GUERCIO; R. LANCIA; M. MESSORI; G. STEFANI; A. VACCARI ( 1994 ) - VAPOR-PHASE HYDROGENATION OF MALEIC-ANHYDRIDE TO GAMMA-BUTYROLACTONE. 1. ROLE OF CATALYST COMPOSITION - ERDÖL UND KOHLE, ERDGAS, PETROCHEMIE VEREINIGT MIT BRENNSTOFF-CHEMIE - n. volume 47 - pp. da 146 a 149 ISSN: 0367-0716 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Cubic spinel-type phases containing excess copper ions may be obtained by controlled oxidation of homogeneous copper-rich coprecipitates. Partial substitution of the copper ions with other divalent cations leads to considerable modifications in both thermal stability and catalytic properties. Cadmium ions give rise to dramatic deactivation in the hydrogenation of maleic anhydride (MA), while zinc ions favour the hydrogenation of succinic anhydride (SA) to gamma-butyrolactone (GBL). On the other hand, the partial substitution with Mg2+ ions increases the productivity in GBL, inhibiting the reactions of over-hydrogenation and/or hydrogenolysis. When both Mg2+ and Zn2+ ions are present production of GBL is higher and hydrogenolysis essentially does not occur. Furthermore, the Cu/Zn/Mg/Cr catalyst investigated in reaction conditions of industrial interest did not show any scale-up problems or deactivation phenomena with increasing time-on-stream.

G.L. CASTIGLIONI; C. FUMAGALLI; A. GUERCIO; R. LANCIA; M. MESSORI; A. VACCARI ( 1994 ) - VAPOR-PHASE HYDROGENATION OF MALEIC-ANHYDRIDE TO GAMMA-BUTYROLACTONE. 2. ROLE OF REACTION PARAMETERS - ERDÖL UND KOHLE, ERDGAS, PETROCHEMIE VEREINIGT MIT BRENNSTOFF-CHEMIE - n. volume 47 - pp. da 337 a 341 ISSN: 0367-0716 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Not only catalyst composition, but also temperature, pressure and H2/C4 ratio play important roles in vapour phase hydrogenation of maleic anhydride (MA) to gamma-butyrolactone (GBL), affecting both MA conversion and GBL yield. Pressure determines the GBL <-> BDO equilibrium (notwithstanding the presence of excess hydrogen), the H2/C4 ratio affects catalyst activity and life, and the optimum reaction temperature depends considerably on catalyst composition. On the contrary, high temperature activation and regeneration by thermal desorption under high hydrogen flow do not show any advantages. Furthermore, by comparing the catalytic reactivity of MA, succinic anhydride (SA) and their dimethyl-esters (DMM and DMS), it was shown that MA may be considered an actual alternative to ester hydrogenation in GBL production. Low conversion was observed with SA/GBL solution and attributed to a competitive adsorption of GBL on the active sites of the catalyst.

C. FUMAGALLI; G. GOLINELLI; G. MAZZONI; M. MESSORI; G. STEFANI; F. TRIFIRO ( 1993 ) - FACILE AND NOT FACILE REACTIONS FOR THE PRODUCTION OF MALEIC AND PHTHALIC ANHYDRIDES WITH VANADIUM MIXED OXIDES BASED CATALYSTS - CATALYSIS LETTERS - n. volume 21 - pp. da 19 a 26 ISSN: 1011-372X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Vanadium is a key element in the formulation of catalysts for the production of anhydrides by selective vapor oxidation with molecular oxygen. A study of the oxidations of o-xylene, n-butane and benzene on V-P, V-Mo and V-Ti mixed oxides, the commercial catalysts for the synthesis of anhydrides, was carried out. The oxidation of o-xylene on the three catalysts was the most facile reaction leading to high yields in phthalic anhydride; on the contrary in the oxidation of n-butane only V-P mixed oxide was active and selective. V-P mixed oxide is active and selective in the oxidation of all the feedstocks and can be identified as the most polyfunctional catalyst. V-Mo is active and selective in both o-xylene and benzene oxidation and V-Ti only in o-xylene oxidation. Moreover the lesser selectivity in phthalic anhydride observed with V-P and V-Mo mixed oxides has been attributed to parallel oxidation reactions to the formation of phthalic anhydride, evidenced by a higher amount of phthalide.

G.L. CASTIGLIONI; C. FUMAGALLI; R. LANCIA; M. MESSORI; A. VACCARI ( 1993 ) - IMPROVED COPPER CHROMITE CATALYSTS FOR THE HYDROGENATION OF MALEIC-ANHYDRIDE TO GAMMA-BUTYROLACTONE - CHEMISTRY & INDUSTRY - n. volume 0009-3068 - pp. da 510 a 511 ISSN: 0009-3068 [Articolo in rivista (262) - Articolo su rivista]
Abstract

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