二亚(3,4-二甲基)苄基山梨糖醇对聚丙烯非等温结晶及其动力学的影响

Effects of Di-Methyl Dibenzylidene Sorbitol on Nonisothermal Crystallization Characteristics and Kinetics of Polypropylene

分析了透明成核剂二亚(3,4-二甲基)苄基山梨糖醇对聚丙烯(PP)的非等温结晶特性和结晶动力学的影响.由实验结果可知,添加透明成核剂可以使PP结晶速率、结晶温度和结晶度等结晶特征参数有所提高.其中:使半结晶时间t1/2缩短27%以上;Avrami指数n趋于3,表明结晶呈异相三维成核增长;结晶速率常数Zt增加50%以上.在相同条件下,单一加快降温速率,使t1/2和n减小而Zt增大,加快了结晶速率但不利于结晶温度和晶粒分布等结晶特征参数.

The effects of di-methyl dibenzylidene sorbitol on nonisothermal crystallization characteristics and kinetics of polypropylene was analyzed in this article. It is found out that, clarifying agent helped to enhance the crystallization characteristics of crystallization rate, crystallization temperature and crystallinity et al. , and t1/2 was shorten about 27 percent, n was decreased near to 3 being three-dimensional heterogeneous nucleation growth, Zt was increased by 50 percent. Under the same conditions except for cooling rates, it is shown that t1/2 and n were decreased and Zt was increased due to the acceleration of cooling rate, which had adverse impacts on the crystallization characteristics of crystallization temperature and crystalline grain distribution except for crystallization rate.