Isotactic polypropylene(iPP)samples were prepared by sequential co-injection molding(SCIM)and conventional injection molding(CIM).The morphological structures and mechanical properties of the samples were investigated by polarized light microscopy(PLM),two-dimensional wide-angle X-ray diffraction(2 DWAXD)and tensile mechanics test.Results show that cylindritic structures of crystalline morphology are formed in overlap region of skin and core material for strong shear between skin melt and core melt during s...