Non-isothermal Crystallization Behavior and Kinetics of Metallocene Short Chain Branched Polyethylene

The non-isothermal crystallization behavior and kinetics of metallocene short chain branched polyethylene were investigated via DSC at cooling rates from 2.5 to 20°C/min, and subsequent heating at rate of 10°C/min. To verify the effect of molecular weight and-branching content on crystallization, three group samples were chosen: (1) linear polyethylene with low molecular weight and high molecular weight; (2) low molecular weight polyethylene with low branching content and high branching content; (3) high molecular weight polyethylene with low branching content and high branching content. The results show that crystallization temperature, crystallinity, melting temperature and crystallization rate are highly branching content-dependent. Molecular weight effect is less important, compared to branching content. A dramatic decrease of crystallization temperature, crystallinity, crystallization rate and melting temperature was observed for branched samples. The non-isothermal kinetics was analyzed via the methods developed by Gupta and Mo Zhi-shen, and good agreement was obtained.