Synthesis and Characterization of Poly(methyl acrylate) + SiO2 Hybrids.

Poly(methyl acrylate) (PMA) + SiO₂ composites were synthesized via a sol-gel reaction. The base acrylic copolymers with a content of alkoxysilane groups were prepared by co-polymerization of methylacrylate (MA) with 3-(trimethoxysilyl) propylmethacrylate (3MPS) or vinyltrimethoxysilane (VTMS); the products were cocondensed with tetraethylorthosilicate (TEOS). The PMA + SiO₂ hybrids were characterized. Thermal stability of PMA is enhanced by copolymerization with 3-MPS or VTMS and the presence of SiO₂; significant weight loss occurs only above 400 °C. Decomposition temperatures are higher by 20 - 25 K as compared to the initial PMA. During the sol-gel process the trimethoxysilyl groups in PMA/3MPS are transformed into a strong silica network. Two different methods of creation of hybrids were used; ESEM shows that only one of them leads to uniform distribution of silica in polymeric matrices. [ABSTRACT FROM AUTHOR]