微交联结构对聚丙烯的流变性能及发泡性能的影响  

Effect of Light Crosslinked Structure of Polypropylene on Rheological Properties and Foamabilty

作　　者：许治昕[1] 张壮[1] 许祥[1] 管涌[1] 危大福[1] 郑安呐[1] 

机构地区：[1]华东理工大学材料科学与工程学院上海市先进聚合物材料重点实验室超细材料制备与应用教育部重点实验室,上海200237

出　　处：《高分子材料科学与工程》2014年第7期51-55,共5页Polymer Materials Science & Engineering

基　　金：上海市重点学科和重点实验室项目资助(B502;08DZ2230500)

摘　　要：采用自制的不饱和聚酯对线型均聚聚丙烯进行熔融接枝改性。改性后的聚丙烯形成了一种微交联结构,其中凝胶含量约为10%,且凝胶的交联点之间平均相对分子质量达到3.0×105。这种微交联的聚丙烯和未改性的线型聚丙烯相比,具有相近的剪切黏度和熔体流动速率,但熔体弹性明显增加,且有应变硬化行为,其最大拉伸黏度是本体聚丙烯的10倍。因此,微交联结构的引入改善了聚丙烯的发泡性能。以超临界二氧化碳为发泡剂,在不加入成核剂的条件下,得到了泡孔密度为1.1×109cm-3的微孔泡沫塑料。One kind of linear homopolymer isotactic polypropylene （PP） was modified via melt grafting with one unsaturated linear polyester by Hakke Torque Rheometer. The modified PP has a lightly crosslinked structure with gel content of about 10 wt%. In particular, the average molecular weight between the two crosslinking points is around 3.0×10s. Compared with pure PP, the lightly crosslinked PP represents almost the same shear viscosity and melt flow index, but reveals significantly higher melt elasticity and strain hardening behavior. Besides, the maximum extensional viscosity of the crosslinked PP is ten times more than that of the pure PP. As a result, the introduction of the lightly crosslinked structure improves the foamability of the modified PP. Without adding any nuclear agent, PP microcellular foams with cells density of 1.1×109 cm-3 was obtained by batch process using supercritical carbon dioxide as foaming agent.

关 键 词：聚丙烯 交联 流变 微孔泡沫 超临界二氧化碳 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]