Damping properties of interpenetrating polymer networks of polyurethane-modified epoxy and polyurethanes

Interpenetrating polymer networks (IPNs) were prepared from polyurethane (PU)‐modified epoxy with different molecular weight of polyol and polyurethanes based on the mixture of polydiol and polytriol by a one‐shot method. Two types of PU‐modified epoxy: PU‐crosslinked epoxy and PU‐dangled epoxy were synthesized, and the effects of the different molecular weights of polyol in the PU‐modified epoxy/PU IPNs on the dynamic mechanical properties, morphology, and damping behavior were investigated. The results show that the damping ability is enhanced through the introduction of PU‐modified epoxy into the PU matrix to form the IPN structure. As the molecular weight of polyol in PU‐modified epoxy increases, the loss area (LA) of the two types of the IPNs increases. PU‐dangled epoxy/PU IPNs exhibit much higher damping property than that of the PU‐crosslinked epoxy/PU IPNs with 20 wt % of PU‐crosslinked epoxy. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 328–335, 1999