The effect of crystallization on the structure and morphology of polypropylene/clay nanocomposites

The effect of crystallization on the structure and morphology of maleic anhydride grafted polypropylene (PP-MA)/clay (montmorillonite) nanocomposites (PPCNs) is presented. Wide-angle X-ray diffraction (WAXD) measurements of PPCNs crystallized at different temperatures show that the extent of intercalation increases with the crystallization temperature. The enhancement of intercalation occurs with lower clay content PPCNs, and maximum intercalation takes place for 4 wt% clay content. The mechanism of intercalation has been proposed through crystallization. Excess gamma-form of the crystallite of PP-MA appears in presence of clay, possibly because of the confinement of the polymer chain between the clay particles. WAXD data also reveals that d-spacing increases gradually with clay content. The decrease of spherulitic size is observed with increasing clay content, which indicates that clay particles act as nucleating agents. Lamellar textures have been explored by using small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), which exhibit that both the lamellar thickness and long period of the PPCNs are higher than those of PP-MA.