Morphology and impact property of injection-molded PP along the flow direction

This paper studied the variation in morphology and impact property of injection-molded polypropylene (PP) along the flow direction. The polarized light microscopic photographs indicate that the skin thickness gradually diminishes along the flow direction. The X-ray diffractometric analysis reveals that α-phase preponderates in all positions along the flow direction whereas the fraction of β-phase decreases gradually in the same direction. This variation trend in crystal structure leads to a gradual reduction in impact strength of the PP article along the flow path.