Abstract: PP/Talc and PP/CaCO3 composites were prepared by melt mixing. Their crystal morphology and crystalline properties were studied using differential scanning calorimetry and hot stage polarized light microscopy. Results show that the influences of Talc and Calcium carbonate on the crystal morphology and crystalline properties of the PP matrix are different obviously. Talcum powder has clear heterogeneous nucleation effect, which could enable the number of polypropylene spherulite increased and the size reduced. In contrast, there is no significant nucleation of calcium carbonate is observed. For PP/Talc composite, both the Crystallization temperature and melting temperature raised; In PP/CaCO3 composite, the large and perfect spherulite formed, the black cross optical phenomena is observed clearly. Its crystal temperature reduced while its melting temperature is almost not affected.

Key words: polypropylene, CaCO3, Talc, Crystallization