Macroporous poly(vinyl acetate-co-triallyl isocyanurate) resin beads were prepared by suspension polymerization and used as acoustic particles for polyurethane (PU)/epoxy resin (EP) intercrosslinked elastomer matrices. The influences of the beads on the dynamic mechanical and underwater acoustic properties of the matrices were investigated. The results show that the underwater acoustic absorption properties of the matrices were improved by the beads, and this depended on the amount of the beads, the composition ratios of PU to EP, the bead diameters, the matrix thickness, and the water temperature. A comparison of the matrix with a 70/30 composition ratio of PU to EP to one without the beads showed that the average acoustic absorption coefficient of the composite with 5% beads increased from 0.38 to 0.55, and the peak value increased from 0.42 to 0.65, but the composites with 10 and 15% of the beads had lower acoustic absorption coefficients at low frequency and a much higher acoustic absorption coefficient at high frequency. The results also indicate that the beads with smaller diameters had a better enhancing effect on the underwater acoustic properties of the matrices. The results of the dynamic mechanical measurements showed that the damping properties of the composites depended on the composition ratios of PU to EP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.