Preparation and rheological characterization of long chain branching polylactide
Preparation and rheological characterization of long chain branching polylactide
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DOI：
10.1016/j.polymer.2014.02.024
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发表时间：
2014-05
期刊：
影响因子：
4.6
通讯作者：
Jianye Liu;Shijun Zhang;Liying Zhang;Bai Yiqing
中科院分区：
文献类型：
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作者：
Jianye Liu;Shijun Zhang;Liying Zhang;Bai Yiqing
以均苯四甲酸二酐（PMDA）和1，4-亚苯基双恶唑啉（PBOZ）为原料，通过聚乳酸（PLA）的连续反应，成功地合成了长支链聚乳酸（LCB）。通过凝胶渗透色谱（GPC）和流变学研究了由官能团反应生成的LCB的拓扑结构。从线性粘弹性、非线性振荡剪切实验和拉伸实验中的应变硬化可以很容易地获得关于支化结构的定性信息。对于链结构的定量信息，线性粘弹性结合分支-分支分支（BOB）动力学模型被用来预测可能的组成和链的拓扑结构的产品，这是合理地解释了建议的官能团反应机理。结果表明，在这些反应中产生的星形LCB结构对拉伸流动下的应变硬化的增强有显著的贡献。
Long chain branching (LCB) of polylactide (PLA) was successfully prepared by the successive reactions of PLA with pyromellitic dianhydride (PMDA) and 1,4-phenylene-bis-oxazoline (PBOZ) together. The topological structures of the LCB generated from functional group reactions were investigated thoroughly by gel permeation chromatography (GPC) and rheology. Qualitative information about the branching structures could be readily obtained from linear viscoelasticity, nonlinear oscillatory shear experiments and strain hardening in elongational experiments. For quantitative information on chain structure, linear viscoelasticity combined with branch-on-branch (BOB) dynamic model was used to predict probable compositions and chain topologies of the products, which were reasonably explained by the suggested mechanism of functional group reactions. It was found out that the star-like LCB structure generated in these reactions contributed remarkably to the enhancement of strain hardening under elongational flow.