等规聚丁烯-1扩链改性及其超临界CO_(2)发泡行为研究

Chain⁃extended modification of isotactic polybutene-1 and its supercritical CO_(2)foaming behavior

以过氧化二异丙苯(DCP)为引发剂、二甲基二硫代氨基甲酸锌(ZDMC)和季戊四醇三丙烯酸酯(PETA)为双单体,制备出具有长链支化结构和交联结构等规聚丁烯-1(iPB-1),并采用超临界CO_(2)发泡制备iPB-1发泡材料。研究扩链改性对iPB-1的熔融结晶、流变行为和发泡行为的影响。结果表明,长链支化结构提高了iPB-1的结晶温度并降低了iPB-1结晶度;改性iPB-1的熔体黏弹性提高、松弛时间增加、剪切稀化现象更为明显,同时表现出显著的应变硬化现象;长链支化改性iPB-1具有更宽的发泡温度区间和更均匀的泡孔结构。

Isotactic polybutene⁃1(iPB⁃1)with a long⁃chain branching and cross⁃linking structure was prepared by using di⁃cumyl peroxide as an initiator and zinc dimethyldithiocarbamate(ZDMC)and pentaerythritol triacrylate as dual mono⁃mers.Then,iPB⁃1 foams were prepared through supercritical CO_(2)foaming.The effects of chain⁃extended modification on the melting,crystallization,rheological,and foaming behaviors of iPB⁃1 were investigated.The results indicated that the long⁃chain branching structure resulted in an increase in the crystallization temperature of iPB⁃1 but a decrease in its crystallinity.The modified iPB⁃1 obtained an improvement in the melt viscoelasticity and relaxation time,resulting in more remarkable shear thinning along with a significant strain⁃hardening phenomenon.The modified iPB⁃1 with a long⁃chain branching structure exhibited a wider foaming temperature window and a more uniform cellular structure.