Silicon-based materials prepared by IPN formation and their properties

Both “condensation” and “hydrosilylation” reactions have been successfully applied to the synthesis of silicon-based interpenetrating polymer networks (IPNs) consisting of a stable Si—O and/or a Si—C linkage. A ladder silsesquioxane oligomer (LDS 1, commercial name: Glass Resin™ GR100) and a polycarbosilane (PCS) by hydrosilylation polymerization of bifunctional Si—H and Si—vinyl monomers were used as the two components for the IPN (Table I). Si-based IPN material was prepared by melt-and-compression-molding method of the B-staged resin. Evaluating the flow-curing nature of the B-staged resin thus obtained with a KOKA-type flow tester led to suitable conditions for melt-and-compression molding. LDS/PCS materials with various shapes (3–4 mm thick) were prepared by melt-and-compression molding. The mechanical properties of the LDS/PCS materials were evaluated. The flexural modulus and Izod impact strength of LDS/PCS (8:2 w/w) were larger than those of each component, a tendency that proved to be a positive effect derived from IPN formation in the LDS/PCS combined system. In addition, the thermal, electrical, and optical properties of these silicon-based materials were studied and are reported on.