The glass transition behavior of hyperbranched polymer (HBP) molecules with suspensions of silica and glass particles up to the concentrated regime (25 vol %) was analyzed by modulated differential scanning calorimetry (MDSC). The reversing and nonreversing components of the MDSC signal were measured on suspensions of untreated and silylated particle of size in the nanometer and micrometer ranges. The heat capacity step (ΔC p ) at the glass transition of the HBP was found to be independent of silica loading for microparticles, whereas it decreased with increasing particle amount in the case of nanoparticles. A similar behavior was observed for the enthalpy relaxation. These changes in chain dynamics and the progressive suppression of aging were attributed to immobilization effects of the HBP at the surface of the particles, which became detectable only in the case of a very high specific surface. The immobilized HBP fraction was assumed to form a shell of constant thickness around individual particles and was calculated from the ΔC p at the transition. In the case of untreated particles with a silanol surface, the immobilized shell was formed by HBP molecules H-bonded to the particles. The thickness of the shell was found to be equal to 1.9 nm, which corresponded to half the size of the HBP. In the case of methacrylsilane-treated silica, the immobilized shell thickness was found to be equal to 1.3 nm, which corresponded to a monolayer of covalently bound silane.

In this study (0-3) P(VDF-TrFE)/BaTiO 3 composites containing up to 60 vol% of ceramic phase were prepared by solvent casting or compression molding. Their thermomechanical, dielectric, and piezoelectric properties were investigated, and discussed in the light of the properties of the basic components, the processing route and the resulting morphology. The crystalline structure of the P(VDF-TrFE) matrix was found to be highly dependent on the processing route, while the structure of BaTiO 3 was not affected by any of the processing steps. The mechanical properties of the solvent cast materials showed a maximum at 30 vol% BaTiO 3 , while they increased monotonically with BaTiO 3 content for compression molded materials. This difference was attributed to a higher amount of porosity and inhomogeneities in the solvent cast composites. Permittivity as high as 120 and piezoelectric coefficient d 33 up to 32 pC/N were obtained for compression molded composites, and the observed decrease in d 33 with aging time was attributed to the effect of mechanical stress release in the polymer matrix.

and their thermal, viscoelastic and dielectric properties were investigated. When surface modified BaTiO 3 was used, it was possible to decrease both the viscoelastic and the dielectric losses of highly filled solvent cast films, while their storage modulus and relative permittivity either increased or remained equal, owing to reduced porosity and improved matrix-filler compatibility. The effect of BaTiO 3 surface modification on the morphology of compression molded films was less marked, leading to unchanged viscoelastic properties, and lower permittivity and dielectric losses. For all composites the frequency dependency of the dielectric properties at low frequencies was suppressed with modified BaTiO 3 .

Photoinduced processes have gained considerable attention in polymer science and have greatly implemented the technological developments of new products. Therefore, a large amount of research work is currently developed in this area: in this paper we illustrate the advantages of a chemistry driven by light, the present perspectives of the technology, and summarize some of our recent research works, honoring the memory of Prof. Aldo Priola who passed away in March 2021 and was one of the first scientists in Italy to contribute to the field.

Biobased monomers have been used to replace their petroleum counterparts in the synthesis of polymers that are aimed at different applications. However, environmentally friendly polymerization processes are also essential to guarantee greener materials. Thus, photoinduced polymerization, which is low-energy consuming and solvent-free, rises as a suitable option. In this work, eugenol-, isoeugenol-, and dihydroeugenol-derived methacrylates are employed in radical photopolymerization to produce biobased polymers. The polymerization is monitored in the absence and presence of a photoinitiator and under air or protected from air, using Real-Time Fourier Transform Infrared Spectroscopy. The polymerization rate of the methacrylate double bonds was affected by the presence and reactivity of the allyl and propenyl groups in the eugenol- and isoeugenol-derived methacrylates, respectively. These groups are involved in radical addition, degradative chain transfer, and termination reactions, yielding crosslinked polymers. The materials, in the form of films, are characterized by differential scanning calorimetry, thermogravimetric, and contact angle analyses.