茂金属聚乙烯的非等温结晶动力学

对茂金属催化和传统工艺生产的聚乙烯的非等温结晶行为进行了研究，用ＤＳＣ测试了两种聚乙烯的非等温结晶过程，对所得数据分别用Ｏｚａｗａ方程和莫志深方法进行了处理，发现：由于茂金属聚乙烯有着较高的立构规整性．所以虽然它的分子链较长，但结晶速率高于传统聚乙烯，两种聚乙烯非等温结晶过程中的成核和生长机理也不同，茂金属聚乙烯的生长维数高于传统聚乙烯

KINETICS OF NONISOTHERMAL CRYSTALLIZATION OF METALLOCENE POLYETHYLENE

The kinetics of nonisothermal crystallization of metallocene catalyzed and conventional polyethylenes were studied by differential scanning calorimetry.(DSC) at various scanning rates. The theory of Ozawa and method of Mo Zhishen for nonisothermal crystallization were used to analyze the differntial scanning claorimetry data. As a result of these studies, the Ozawa index of metallocaene catalyzed polyethylene was higher than that of conventional polyethylene. This suggested remarkably different crystallization mechanisms of metallocene catalyzed and conventional polyethylenes, and a higher growth dimension of the former. Moreover, being made by single|site catalytic agent, metallocene catalyzed polyethylene had a higher tacticity of molecular chains than conventional polyethylene. Although metallocene catalyzed polyethylene used in this study had a larger molecular weight, it had a higher rate of crystallization and reached a higher degree of crystallinity.=