Crystallization and Melting of Fractions of Branched Polyethylene. 2. Dilatometric and Small-Angle X-Ray-Scattering Study on the Molecular Weight Dependence of Isothermal Crystallization

Abstract

Effects of the molecular weight on the crystallization behaviour of branched polyethylene become observable if isothermal crystallization is studied at temperatures near to the melting end. Crystallinities decrease with decreasing molecular weight. Thicknesses of lamellae grown during isothermal crystallization are independent of the molecular weight. They depend only on temperature. Compared to the effect of the branches polydispersity gives only a minor contribution to the broadening of the crystallization and melting range of low density polyethylene.