Dynamic mechanical properties of polysiloxane-modified, castor oil-based polyurethane/epoxy interpenetrating polymer network composites

A series of hydroxyl-terminated poly dimethyl siloxane (HTPDMS)-modified polyurethane (PU)/epoxy resin (EP) graft interpenetrating polymer network (IPN) composites were prepared. The morphologies of impact fracture surfaces, tensile and impact strengths, damping properties as well as thermal stability properties of the HTPDMS modified IPN composites were studied systematically. The results revealed that the impact strength of the IPN composites could be significantly improved after the incorporation of HTPDMS, whereas the tensile strength of the composites was impaired when the HTPDMS content were more than 5%. The studies also showed that the addition of HTPDMS can improve the damping properties of pure PU/EP IPN and can improve the thermal decomposition temperature. It is expected that the modified IPN composites may be used as structural damping materials.