<正>The effect of compatibility on phase morphology and orientation of isotactic polypropylene （iPP） blends under shear stress was investigated via dynamic packing injection molding （DPIM）. The compatibility of i’PP blended with other polymers

namely

atactic polypropylene （iPP）

octane-ethylene copolymer （POE）

ethylene-propylene-diene rubber （EPDM） and poly（ethylene-co-vinyl acetate） （EVA）

have first been studied using dynamic mechanical analysis （DMA）. These blends were subjected to DPIM

which relies on the application of shear stress fields to the melt/solid interfaces during the packing stage by means of hydraulically actuated pistons. The phase morphology

orientation and mechanical properties of the injection-molded samples were characterized by SEM

2D WAXS and Instron. For incompatible iPP/EVA blends

a much elongated and deformed EVA particles and a higher degree of iPP chain orientation were observed under the effect of shear. However

for compatible iPP/aPP blends

a less deformed and elongated aPP particles and less oriented iPP chains were deduced. It can be concluded that the compatibility between the components decreases the deformation and orientation in the polymer blends. This is most likely due to the hindering effect

resulting from the molecular entanglement and interaction in the compatible system.