POLYURETHANE-POLYSTYRENE INTERPENETRATING NETWORKS

A series of polyurethane based on liquid chloroprene-hydroxyethyl methacrylate copolymer(CP-co-HEMA)-polystyrene (PS) interpenetrating polymer networks (PU-PS IPN) were synthe-sized. Some physical properties were examined and density behavior was investigated. In 60% polyurethane (PU) system, the tensile strength and density increased greatly. Transmission electronmicrographs showed that the phase separation existed and the sizes of PS domains dispersed in PUphase were about 500-4,000 A. In comparison with correlative PU-PMMA IPN system,which has the higher compatibility,this system showed an extensive phase separation and clear boundaries.There was no phase inversion observed even for 60% PU system in which PS was still the dispersed phase and PU the continuous phase.This was due to the relatively faster rate of formation of PU than that of ST polymerization.