Damping properties and the morphology analysis of the polyurethane/epoxy continuous gradient IPN materials

As engineering materials, the gradient polymer with high modulus as well as excellent damping properties are of great interest in aerospace and automotive industries for severe dynamic environment. A new type of continuous gradient polyurethane/epoxy interpenetrating polymer network (IPN) material was realized according to the self-stratification mechanism in this paper. Dynamic mechanical analysis (DMA) tests showed that it undergoes more than 117.69 °C with loss tangent larger than 0.3, much better than the traditional IPN with the same component. Morphological analysis revealed that the polyurethane phase dominated IPN concentrated in one surface of the samples while the epoxy phase in the other, it was continuous gradient shifting from one surface to the other with no obvious phase separation.