Nuova ricerca


Personale tecnico amministrativo
Dipartimento di Ingegneria "Enzo Ferrari"

Home |


2014 - Facile synthesis of B-type carbonated nanoapatite with tailored microstructure [Articolo su rivista]
Gualtieri, M. L.; Romagnoli, M.; Hanuskova, M.; Fabbri, E.; Gualtieri, A. F.

Nanolime and a phosphate-based chelating agent were used to synthesize B-type carbonated apatite. Developed Rietveld refinement strategies allowed one to determine process yield, product crystallinity as well as structural (unit cell) and microstructural (size, strain) parameters. The effect of synthesis temperature (20-60 °C) as well as Ca/P ratio (1.5-2.5) and solid content (10-30 wt%) of the starting batch on these properties were investigated. FTIR, TEM and gas adsorption data provided supporting evidence. The process yield was 42-60 wt% and found to be governed by the Ca/P ratio. The purified products had high specific surface area (107-186 m2/g) and crystallinity (76-97%). The unit cell parameters, correlated to the degree of structural carbonate, were sensitive to the Ca/P ratio. Instead, temperature governed the microstructural parameters. Less strained and larger crystals were obtained at higher temperatures. Long-term aging up to 6 months at 20 °C compensated for higher crystal growth kinetics at higher temperature. © 2014 Elsevier Inc.

2014 - Preparation of scratch resistant superhydrophobic hybrid coatings by sol-gel process [Articolo su rivista]
Taurino, Rosa; Fabbri, Elena; Pospiech, Doris; Synytska, Alla; Messori, Massimo

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.

2014 - Thermo-mechanical and impact properties of polymeric foams used for snow sports protective equipment [Relazione in Atti di Convegno]
Nicotra, Marco; Moncalero, Matteo; Messori, Massimo; Fabbri, Elena; Fiorini, Maurizio; Colonna, Martino

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.

2011 - TiO2-SiO2 hard coating on polycarbonate substrate by microwave assisted sol-gel technique [Articolo su rivista]
Dinelli, Martina; Fabbri, Elena; Bondioli, Federica

To enhance the poor scratch resistance ofpolycarbonate, a silica (SiO2) and titania (TiO2) transparentinorganic coatings was designed and synthesized using amicrowave assisted sol–gel heating. Due to the transparencyof PC to microwave, the idea was to obtain a localizedheating only on the coating film. The obtained films werefully characterized to mainly evaluate the effect of titaniacontent, added both as nanoparticles and from tetraethylorthotitanate, TEOT, on scratch resistance and surfacemorphology. Particular attention was paid to preserve thetransparency of the final product. The results allowed todefine that TEOT addition enhances the adhesion betweencoating and polycarbonate, even if the optimized quantityhave to be defined in order to avoid a decrease of coatingmechanical resistance. In this work optimized TEOT levelresults to be the associated to 5 wt% of TiO2, which enablethe better balancing between adhesion and mechanicalresistance performances.

2008 - Facile preparation of superhydrophobic coatings by sol–gel processes [Articolo su rivista]
R., Taurino; Fabbri, Elena; Messori, Massimo; Pilati, Francesco; D., Pospiech; A., Synytska

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°.

2006 - Preparation and characterization of epoxy resins filled with submicron spherical zirconia particles [Articolo su rivista]
Bondioli, Federica; Cannillo, Valeria; Fabbri, Elena; Messori, Massimo

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.

2005 - Epoxy-silica nanocomposites: Preparation, experimental characterization and modeling [Articolo su rivista]
Bondioli, Federica; Cannillo, Valeria; Fabbri, Elena; Messori, Massimo

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.

2005 - Perfluoropolyether-silica hybrids: preparation and surface characterization [Articolo su rivista]
Messori, Massimo; M., Toselli; Pilati, Francesco; Fabbri, Elena; Fabbri, Paola; Pasquali, Luca; Montecchi, Monica; Nannarone, Stefano; C., Tonelli

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.

2004 - Prevention of plasticizer leaching from PVC medical devices by using organic-inorganic hybrid coatings [Articolo su rivista]
Messori, Massimo; A., Toselli; F., Pilati; Fabbri, Elena; P., Fabbri; Pasquali, Luca; S., Nannarone

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.

2004 - Surface modification of unsaturated polyester resins with perfluoropolyethers [Articolo su rivista]
Fabbri, Elena; Fabbri, Paola; Messori, Massimo; Pilati, Francesco; C., Tonelli; M., Toselli

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.

2003 - Flame Retarding Poly(Methyl Methacrylate) with Nanostructured Organic-Inorganic Hybrids Coatings [Articolo su rivista]
Messori, Massimo; M., Toselli; Pilati, Francesco; Fabbri, Elena; P., Fabbri; S., Busoli; Pasquali, Luca; S., Nannarone

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.