Abstract: The effect of molecular weight and molecular weight distribution( MWD) on the properties of polypropylene(PP)was studied by addition of DCP. The reaction of DCP resulted in lower molecular weight and narrower MWD of PP, and the crystallization rate increased, the spherulite size decreased and β phase vanished, which improved the transparency. When the content of the nucleating agent(TM-3)and theDCP were 0.4%and 0.05%,respectively, the best transparency of PP was ob- served. However, the mechanical properties of PP decreased slightly with reduced molecular weight and narrowed MWD.

Key words: molecular weight, molecular weight distribution, polypropylene, nucleation;property