Amphiphilic poly(styrene-b-ethylene oxide) block copolymers were synthesized by sequential anionic copolymerization. Layered silicates intercalated by the block copolymers were prepared via melt intercalation. The effects of the intercalated clay on an acrylonitrile-butadiene-styrene resin were characterized with X-ray diffraction, transmission electron microscopy, stress-strain measurements in elongation, and thermogravimetric analysis. X-ray and microscopy results demonstrated that the main structure of the dispersed block-copolymer-intercalated clay in the acrylonitrile-butadiene-styrene resin matrix was mono- and bundle-layered. Further studies demonstrated that the resin showed considerable improvement in its tensile strength, modulus, and thermal stability. (C) 2004 Wiley Periodicals, Inc.