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

Interpenetrating polymer networks (IPNs) were prepared from polyurethane (P U)-modified epoxy with different molecular weight of polyol and polyurethan es 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, morp hology, and damping behavior were investigated. The results show that the d amping ability is enhanced through the introduction of PU-modified epoxy in to the PU matrix to form the IPN structure. As the molecular weight of poly ol in PU-modified epoxy increases, the loss area (LA) of the two types of t he IPNs increases. PU-dangled epoxy/PU IPNs exhibit much higher damping pro perty than that of the PU-crosslinked epoxy/PU IPNs with 20 wt % of PU-cros slinked epoxy. (C) 1999 John Wiley & Sons, Inc.