SEM study of a polystyrene/clay nanocomposite

We carried out a scanning electron microscopy study to investigate the morp hology of a polystyrene (PS)/montmorillonite nanocomposite. Monodispersed s pherical particles, about 200 nm in diameter, were observed when PS/montmor illonite powder was dispersed in water, whereas planar silicate sheets were found for cetyltrimethylammonium bromide-exchange montmorillonite. The fra cture surface of a PS/clay nanocomposite pellet sample showed a lot of fibr ils rather than the smooth surface of a pure PS pellet. After the PS/clay n anocomposite pellet was chemically etched, flaky montmorillonite particles were homogeneously dispersed in the PS matrix. A film sample, prepared by t he pressing of the PS/clay nanocomposite melt, revealed that the montmorill onite primary particles oriented parallel to the surface, and the correspon ding X-ray diffraction distribution map of silicon atoms confirmed that the dispersed particles were montmorillonite primary particles. (C) 2002 John Wiley & Sons, Inc.