Abstract: The isothermal and non-isothermal crystallization behavior of special material PP(K9928), a kind of high fluidity and high impact polypropylene, had been investigated by differential scanning calorimetry(DSC), and a further comparison with a typical PP(K7726H) in domestic market had been made. The results indicate that the onset crystallization temperature of K9928 was 3~5 ℃ higher than the contrastive sample and the higher crystallization rate could be observed for K9928 at low cooling rate. However, the span from onset temperature to end temperature was wider when the cooling rate is higher than 50 ℃/min, which leaded to a longer crystallization duration. Impact resistance of K9928 depended on its more block copolymers with similar structure.

Key words: polypropylene, high fludity, high impact strength, crystallization behavior