Preparation and Characterization of Hybrid Nanocomposites Coated on LDPE

Hybrid organic-inorganic nanocomposites containing hyperbranched structures (HBP) were prepared through a dual-curing process, which involves photopolymerization and alkoxysilane groups condensation. In particular, an oligomer containing polyethylene oxide (PEO) units and alpha,omega-methacrylate groups (BEMA 1400) was used together with a hyperbranched polymer bearing acrylic groups as the organic phase precursors. Methacryloyloxypropyltrimethoxysilane (MEMO), as the organic-inorganic linker, and tetraethoxysilane (TEOS), as inorganic phase precursor, were also employed. The kinetics of both photopolymerization and condensation reactions was investigated by double bond conversion analysis (via FT-IR) and weight loss determination, respectively. The mobility of the organic phase was studied by means of DSC and dynamic mechanical analyses (DMTA) and correlated with hybrid composition. TEM analyses performed on microtomized film slices indicated the formation of nanometric silica domains. Hybrids were coated onto LDPE film previously subjected to a plasma treatment and substrate-coating interfacial adhesion was investigated through stress-strain and DMTA experiments.