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.