In this study, we prepared polystyrene (PS) resin nanocomposites with antistatic properties by melt-blending PS with nanoscale zinc oxide (ZnO). The effects of nanoscale ZnO on the electrical and physical characteristics of the PS nanocomposites were investigated. Two kinds of nanoscale powders, spherical zinc oxide (s-ZnO) and zinc oxide whisker (w-ZnO), were selected. The coupling agents vinyltriethoxysilane (VTES) and phenyltriethoxysilane (PTES) were used to improve the compatibility between the nanopowders and PS resin. The addition of s-ZnO and w-ZnO improved the antistatic characteristics of the materials. The surface resistivities of the s-ZnO and w-ZnO nanocomposites were significantly reduced by modification with VTES and PTES. The addition of ZnO nanopowder increased the flexural modulus and reduced the flexural strength. The silane coupling agents improved the flexural properties of the nanocomposites. The glass-transition temperatures and thermal degradation temperatures of the ZnO/PS nanocomposites increased with ZnO content. Treatment with silane increased the glass-transition temperatures and thermal degradation temperatures of the composites. (c) 2005 Wiley Periodicals, Inc.