Rheological and Crystalline Behaviour of Long Chain Branched Polylactic Acid Prepared by Transesterification Reaction

被引：0
|
作者：
Yang Z. [1 ,2 ]
Luo Z. [1 ,2 ]
Yang L. [1 ,2 ]
Zhang F. [1 ,2 ]
Xie L. [1 ,2 ]
Zheng Q. [3 ]
机构：
[1] Department of Polymer Materials Engineering, College of Materials and Science Metallurgy Engineering, Guizhou University, Guiyang
[2] National Engineering Research Center for Compounding and Modification of Polymeric Materials, Guiyang
[3] Department of Polymer Science and Engineering, Zhejiang University, Hangzhou
来源：
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | 2019年 / 35卷 / 02期
关键词：
Crystallization behavior; Long chain branching; Melt branching; Polylactic acid; Rheological behavior;
D O I：
10.16865/j.cnki.1000-7555.2019.0039
中图分类号：
学科分类号：
摘要：
Melt-branching modification of linear polylactic acid (PLA) was carried out in the presence of nano-zinc oxide (nano-ZnO) as accelerant, and tri-functional monomer pentaerythritol triacrylate (PETA) as branching center via a method of transesterification reaction. Results show that PLA with long branching chains without gel is obtained and the reaction mechanism of the melt branching reaction is ester exchange. The addition of nano-ZnO could promote the branching reaction of PLA and PETA obviously, and in addition, the molecular weight distribution becomes wider compared with the virgin linear PLA. A shoulder generated owing to the introduction of long branches in the molecular weight distribution curve. When the nano-ZnO content is 0.2 phr, the melt strength of the prepared LCBPLA is increased from 0.02 N to 0.11 N. And the nano-ZnO also promotes the degradation, the melt strength of PLA decreases with the increase of accelerant content. Differential scanning calorimetry (DSC) results reveal the faster crystallization rate and lower crystallization onset temperature in LCBPLA than that of PLA, which are due to the presence of LCB, promoting the crystallization of the system, resulting in the increase of crystallinity and the decrease of spherulites growth rate. The modified PLAs are the mixtures of linear chains and branched macromolecules, which form a double melting peak in the DSC curves, and the branching parts of which the completeness is poor would melt first. © 2019, Editorial Board of Polymer Materials Science & Engineering. All right reserved.
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页码：54 / 60
页数：6
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