Shear-induced ordered structure in polystyrene/clay nanocomposite

A shear-induced ordered structure in an exfoliated polystyrene (PS)/clay na nocomposite is reported. X-ray diffraction (XRD),transmission electron micr oscopy (TEM), and infrared dichroism techniques have been employed to inves tigate the shear-induced ordered structure in the exfoliated PS/clay nanoco mposite. Compared with the broad amorphous peaks before extrusion, a series of sharp diffraction peaks were observed in XRD pattern for the extruded P S/clay nanocomposite pellet sample, showing that an ordered structure occur red under shear flow. TEM images confirmed directly that the origin of the ordered structure was mainly due to the planar orientation of the primary p articles of silicate layers as well as local ordered microstructure of the primary particles, induced by shear flow. The infrared dichroism study indi cated that the phenyl group of PS apparently oriented parallel to the film surface, whereas no obvious orientation of the aliphatic chain could be obs erved. Based on these investigations, a possible mechanism was deduced for the formation of the ordered structure induced by shear flow in the exfolia ted PS/clay nanocomposite.