快速压致凝固聚乙烯结晶结构的研究

Study on Crystal Structure of Polyethylene Solidified under Rapid Compression

利用快速增压、自然冷却和液氮淬冷3种方法对高密度聚乙烯(HDPE)和线性低密度聚乙烯(LLDPE)熔体进行处理,并对凝固样品的微观结构进行了研究。结果表明,由于不受导热系数的限制,快速增压法制备的样品不存在明显的皮芯结构,样品的结晶度分布较均一。和淬冷法相比较,快速增压法也可以有效地抑制聚合物的结晶,特别是对于分子链运动能力较差的高分子材料(LLDPE),抑制作用更明显。

High-density polyethylene （HDPE） melt and linear low-density polyethylene （LLDPE） melt were solidified through three kinds of experimental processes, including rapid compressing, natural cooling and quenching,and then the microstructure of samples was investigated. The results show that the erystallinity distribution of rapid compressing samples was more uniform regardless of low thermal diffusivity of polymers, so the ＂skin-core＂ type of crystallinity distribution was not found in RC samples. In addition, compared with quenching, rapid compressing can also hinder the crystallization of the polymer melt effectively,especially for LLDPE with low mobility of molecular chains.