Elastic factors controlling sorption and transport properties of polyethylene

摘要: The const rainment of the noncrystalline regions in polyethylene samples with various thermal and mechanical histories has been determined from measurements degree to which activity para-xylene sorbed polymer is enhanced relative its hypothetical value absence crystallites. With increasing temperature, enhancement decreases smoothly vanishes at melting point (∼135°), while crystallinity remains virtually constant below 100°C. This dependence solvent on temperature rather than coupled observation that behavior reversible suggests tension intercrystalline tie chains equilibrium free energy driving force crystallization. Thermodynamic analysis provides a means calculating fraction incorporated chains. elastically effective increases 0.25 0.35 rate cooled melt, approaches unity for highly oriented, cold-drawn samples. ineffective presumably consists chain folds, loops, ends, short molecules.