支化改性聚乳酸及其对发泡行为的影响  

Preparation of Branched Poly(Lactic Acid) and its Foaming Behaviors

作　　者：郝明洋[1,2,3] 王昌银[2,3] 蒋团辉[2] 张纯[2] 何力[2] 龚维[1,2] 

机构地区：[1]贵州师范大学材料与建筑工程学院,贵州贵阳550014 [2]国家复合改性聚合物材料工程技术研究中心,贵州贵阳550014 [3]贵州大学材料与冶金工程学院,贵州贵阳550025

出　　处：《高校化学工程学报》2016年第1期156-161,共6页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金项目(21264004);贵州省科技厅重大专项(2012-6023);黔科合人才团队[2014]4006号

摘　　要：采用多官能度环氧化合物,通过官能团反应制备支化结构聚乳酸。通过动态剪切流变仪和差示扫描量热仪(DSC)分别考察了聚乳酸流变行为和结晶行为,结果表明改性之后聚乳酸的黏弹性显著提高,尤其是弹性响应,通过Cole-Cole图和Han图反映了支化结构的引入,此外,DSC表征结果表明改性后聚乳酸出现了明显的降温结晶峰,进一步映证了支化结构的存在。同时,利用型腔体积可控注塑发泡装备制备了聚乳酸发泡试样,结果表明支化结构的引入显著改善了聚乳酸的发泡行为。在泡孔生长动力学研究的基础上,将泡孔生长过程分为快速生长阶段和慢速生长应力松弛阶段,分析了聚合物熔体黏弹性对泡孔生长、稳定过程的影响,较高的黏弹性起到了抑制泡孔合并、恶化的作用。同时,改性之后聚乳酸结晶性能提高,有利于发泡过程中泡孔结构的稳定。Branched poly（lactic acid） was prepared via functional group reactions using a multifunctional epoxy compound. The rheology and crystallization behavior of PLA and modified PLA were investigated by dynamic shear rheometer and differential scanning calorimeter（DSC）, respectively. It was found that the rheological property, especially the elastic response of the modified PLA was dramatically improved comparing to the original PLA, and the introduction of chain branching was proved through Cole-Cole graph and Han graph. In addition, the modified PLA showed obvious crystallization peak, which further proved the existence of chain branching. Meanwhile, PLA and modified PLA foams were prepared using an injection molding machine equipped with volume-adjustable cavity. It was found that the introduction of chain branching improved the foaming behavior of PLA. Based on the bubble growth kinetics, the cell growth process was divided into rapid growth stage and slow growth stage to analyze the effect of polymer viscoelasticity on cell growth and stabilization. High viscoelasticity response suppressed cell coalescence and deterioration. In addition, the crystallization property of the modified PLA was improved comparing to that of the original PLA, which can be contributed to the cell structure stabilization during foaming.

关 键 词：聚乳酸 支化 黏弹性 结晶行为 发泡 泡孔结构 

分 类 号：TQ328.2[化学工程—合成树脂塑料工业]