Abstract
Epoxy/silica hybrid materials showing no glass transition behavior have been reported to be prepared by in-situ polymerization of alkoxyl groups of 3-glycidyloxypropyl-trimethoxysilane (GPTMS) in epoxy resin oligomers. The effects of water content on the in-situ polymerization of GPTMS and the curing of epoxy oligomer were investigated in detail. The phase structure and dielectric properties of the hybrids were evaluated. It was revealed that with no added water the alkoxyl groups of the GPTMS react with the hydroxyl groups generated by the ring opening reaction of the epoxy groups. A homogeneous structure, where the inorganic component was uniformly distributed in the matrix, was formed. In the presence of the stoichiometric amount of water, on the other hand, inorganic siloxane networks were formed nearly completely through the sol-gel reaction. A heterogeneous structure, where a nano-meter-order inorganic phase was clearly separated in the epoxy resin matrix, was observed.
