Crystallization kinetics and mechanical properties of polyethylene

Abstract

Abstract The kinetics of crystallization of a branched polyethylene have been studied dilatometrically, spectroscopically, and microscopically at small degrees of supercooling (ca. 0–10°C.). In order to assess the extent to which results of different methods are in agreement with each other, apparent induction times and maximuin crystallization rates are compared. On the basis of these data, the results of different experimental techniques using different types of sample are in general agreement. However, there do exist small, but significant, differences which appear to be outside experimental error. The results are shown to be in essential agreement with present theories of nucleation and of crystallization. The observations are interpreted in terms of the processes occurring during crystallization. The relationship of dynamic mechanical properties to previous thermal histories is considered and a qualitative interpretation is presented.