Abstract: The nonisothermal crystallization behavior of ethylenepropylene random copolymer(PPR) with and without β nucleating agents was studied. The addition of β nucleating agents increased the peak crystallization temperature of PPR. At the same cooling rate，the t1/2 and Zc of β nucleating agent modified PPR was more and less than of those of weat PPR. Meanwhile the required cooling rate of pristine PPR was smaller than that of PPR containing β nucleating agents to get the same crystallinity，which shows that the addition of β nucleating agents can decrease the crystallization rate of PPR. Mo method can describe nonisothermal crystallization behavior of PPR and β nucleating agent modified PPR very well.

Key words: non-isothermal crystallization kinetics, amide βnucleating agent, random polypropylene