Abstract:

This paper reported an investigation on the melt crystallization properties， optical properties， molecular weight distribution， mechanical properties， capillary rheological properties， and thermal shrinkage properties of four types of transparent polypropylene （PP） specialized for injection molding. The results indicated that the K4860H?type PP presented a narrower molecular weight distribution， better toughness， and a higher transparency degree than the other three types of PP. The K4860H?type and MT45S?type PP exhibited higher crystallization temperatures and faster crystallization rates than the other two types of PP， representing a better crystallization capability. Moreover， the K4860H?type PP showed a similar molding shrinkage to the 500B?type one， indicating a good dimensional stability for thin?wall injection molding. Based on the above analysis， the main performance of the K4860H?type PP is superior to that of the other three types of PP.

Key words: polypropylene, transparency, thin?wall injection molding, structure, performance, analysis