Using a two-stage emulsion polymerization method, a series of poly(methyl methacrylate-acrylonitrile)/poly(ethyl acrylate-n-butyl acrylate) [P(MMA-AN)/P(EA-nBA)] latex interpenetrating polymer networks (LIPNs) were synthesized by varying AN content, ratio of network I/network III crosslinker content. and introducing chain transfer agent. The damping properties of the LIPNs were investigated using a Rheovibron Viscoelastometer, The results indicates that a suitable content of AN can improve the damping properties of the LIPNs. Three kinds of fillers were incorporated into the LPINs, respectively, to measure the change in the damping properties. Mica and TiO2 both increased the damping properties of the LIPNs over the wide temperature range. For TiO2-filled LIPNs, it was observed that the tan delta values exceeded 0.4 over 112.6 degrees C temperature range from -50 to 72.6 degrees C. (C) 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 722-727, 2000.