POLYURETHANE POLYSILOXANE INTERPENETRATING POLYMER NETWORKS .1. A POLYETHER URETHANE POLY(DIMETHYLSILOXANE) SYSTEM

In the reported experiments, the synthesis and properties of a polyether urethane network based on Adiprene L-100, of a poly(dimethylsiloxane) network and of nine interpenetrating polymer networks based on these polymers were investigated. To form the latter materials, the prepolymers were mixed and crosslinked simultaneously, but by separate mechanisms. Comparison of the network solubility parameters suggested marked incompatibility. Optical microscopy, dynamic mechanical analysis and the tensile testing indicated gross phase separation. From 90 to 50% of the polyether urethane component, this network was continuous and the poly(dimethylsiloxane) was present as dispersed phases. From 40 to 10% of the polyether urethane, the situation was reversed. Some degree of interchain mixing at phase boundaries was detected by **1**3C nuclear magnetic resonance spectroscopy.