effect of soybean oil on dynamic mechanical properties of epoxy/polyurethane ipns

A series of semi-interpenetrating polymer networks (sipn) based on bisphenol a epoxy resin and thermoplastic polyurethane was prepared by solution blending. epoxidized soybean oil (eso) was used to modify the ipns in this study. polymer/eso ratio of the system was changed from 100/0 to 70/30. the effect of soybean oil content on morphology and dynamic mechanical properties of the system was studied systematically. results revealed that the epoxy/polyurethane system with soibean oil showed lower glass transition temperature, lower crosslink density and higher toughness.