Abstract: A shear-induced ordered structure in an exfoliated polystyrene(PS)/clay nanocomposite is reported. Self-assembly behavior was reported for the first time of a shear induced ordered structure in the nanocomposite. The self assembly behavior was measured by X-ray diffraction(XRD) patterns, transmission electron microscopy(TEM), and FTIRdichroism technique. Compared with the broad amorphous peaks of the PS, a series of sharp XRDpeaks were observed for the exturded PS/clay nanocomposite pellet sample, showing that an ordered sructure occurred under shear flow. The intensities of the four sharp XRDpeaks of the ordered sructure decreased significantly with temperature. However, at 95 ℃, the XRDpeaks increased significantly, the FTIRdichroism showing that and the phenyl ring of PSchanged its orientation from parallel to perpendicular to the monmorillonite primary particles, whereas no obvious orientation of the alkyl chain of PScould be found. At₁10 ℃, a disordered structure occurred for the phenyl ring. TEMimages confirmed directly that the origin of the ordered structure was mainly due to the planar orientation of the primary particles of silicate layers as well as local ordered microsructure of the primary particles, induced by shear flow. Basd on these investigations, a possible mechanism was deduced for the formation of the ordered strucure induced by shear flow in the exfoliated PS/clay nanocomposite.

Key words: Nanocomposite material, PS, Montmorillonite, Self-assembly