Differential thermal analysis of pressure crystallized polyethylene

摘要: The results presented here demonstrate that although medium-density polyethylene in addition to linear can crystallize extended-chain as well folded-chain crystals, the branches have a significant effect on ease of forming crystals. Besides two types crystals having different melting points, measured by DTA, an endothermic peak assumed be due onset rotational motion and located just below respective peaks is associated with each type crystal. Melting itself does not result complete disappearance order; if sample held above point for short period time sufficient seed nuclei remain produce crystallization at higher temperature than commensurate cooling rate employed. This atmospheric pressure takes place through chain folding even though are remnants In fractionation segregation molecular weight during under pressure, which some further evidence presented, obtained suggest branching content may also occur.