星型支化改性聚乳酸的超临界CO_(2)发泡行为研究  

Study on Supercritical Carbon Dioxide Foaming Behavior of Star-Shaped Branched Modified Polylactic Acid

作　　者：向耀兴 张天萍 甄卫军[1] 赵玲[1] XIANG Yao-xing;ZHANG Tian-ping;ZHEN Wei-jun;ZHAO Ling(State Key Laboratory of Chemistry and Utilization of Carbon-based Energy and Resources,Key Laboratory of Fine Chemicals of Petroleum and Natural Gas,Ministry of Education,College of Chemical Engineering,Xinjiang University,Urumqi 830017,China)

机构地区：[1]省部共建碳基能源资源化学与利用国家重点实验室石油天然气精细化工教育部重点实验室新疆大学化工学院,新疆乌鲁木齐830017

出　　处：《塑料科技》2022年第7期15-21,共7页Plastics Science and Technology

摘　　要：采用NDZ-201钛酸酯偶联剂改性的纳米氧化锌(g-ZnO)为促进剂,使聚乳酸(PLA)与多官能团酯类单体(PET4A)发生酯交换反应,制备星型支化PLA。通过超临界CO_(2)发泡工艺,研究g-ZnO添加量对星型支化PLA发泡行为的影响,并对其结构与性能进行表征。结果表明:当g-ZnO质量分数为0.5%时,星型支化PLA的泡孔密度为1.44×10^(9)个/cm^(3),比线型纯PLA的泡孔密度高,发泡倍率也提高至10倍,远高于线型纯PLA。星型支化改性后PLA的热稳定性和结晶度显著提高,最大热分解温度由362.05℃提高至368.16℃,结晶度由6.380%提升至26.580%。交联网状结构的存在使得星型支化PLA的储能模量(G')和损耗模量(G")增大,复数黏度的平台区向低频区迁移,剪切变稀现象更明显,损耗因子更接近于1,故而星型支化体系更有利于PLA发泡。Nano-ZnO modified by NDZ-201 titanate coupling agent(g-ZnO)was used as the promoter to make the transesterification reaction between polylactic acid(PLA)and multi-functional ester monomer(PET4A)to prepare star-shaped branched PLA.The effects of g-ZnO additions on the foaming behavior of star-shaped branched PLA were studied by supercritical CO_(2)foaming process,and structure and properties of star-shaped branched PLA were characterized.The results show that when the mass fraction of g-ZnO is 0.5%,the pore density of star-shaped branched PLA is 1.44×10^(9)cell/cm^(3),which is higher than that of linear pure PLA,and the foaming rate is also increased to 10 times,which is much higher than that of linear pure PLA.The thermal stability and crystallinity of PLA after star-shaped branched modification are significantly improved.The maximum thermal decomposition temperature is increased from^(3)62.05℃to 368.16℃,and the crystallinity is increased from 6.380%to 26.580%.Due to the existence of cross-linked network structure,the storage modulus(G')and loss modulus(G'')of star-shaped branched PLA increase,the platform region of complex viscosity migrates to the low frequency region,the shear thinning phenomenon is more obvious,and the loss factor is closer to 1.Therefore,the star-shaped branched system is more conducive to PLA foaming.

关 键 词：聚乳酸 星型支化 超临界CO_(2) 发泡行为 

分 类 号：TQ328.9[化学工程—合成树脂塑料工业]