Structure variation of tensile-deformed amorphous poly(l-lactic acid): Effects of deformation rate and strain
Structure variation of tensile-deformed amorphous poly(l-lactic acid): Effects of deformation rate and strain
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DOI：
10.1016/j.polymer.2011.07.003
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发表时间：
2011-08
期刊：
影响因子：
4.6
通讯作者：
Xiuqin Zhang;K. Schneider;Guoming Liu;Jianhong Chen;K. Brüning;Dujing Wang;M. Stamm
中科院分区：
文献类型：
--
作者：
Xiuqin Zhang;K. Schneider;Guoming Liu;Jianhong Chen;K. Brüning;Dujing Wang;M. Stamm
目前的工作通过研究变形介导的分子取向和结晶来探索生物聚合物聚（L-乳酸）（PLA）的结构-性能相关性。研究了不同应变率下非晶态PLA的结构和形貌变化。结果表明，应变速率显着影响其应变硬化行为。变形PLA的结晶度、取向以及空化随着应变率的增加而增加。结构演变分为三个潜在阶段：（i）在小应变（<100％）下，PLA 的结晶度通过取向诱导结晶而增加； (ii) 在中间应变 (100%–160%) 下，变形 PLA 的结晶度略有下降，这是由于现有晶体在应力作用下破裂，并伴随着新形成的空隙和空腔； (iii) 在高应变（>160%）下，非晶区域中定向链数量的增加促进了 PLA 的结晶。我们的研究表明应变速率和拉伸应变对于调节非晶态 PLA 的结晶和取向起着重要作用。
The present work explored the structure-property correlations for the biopolymer poly(l-lactic acid) (PLA) by studying deformation-mediated molecular orientation and crystallization. The structural and morphological variations of amorphous PLA under different strain rates were investigated. The result showed that strain rate significantly influences its strain-hardening behavior. The crystallinity and orientation as well as cavitation of deformed PLA increase with the increase of strain rates. The structure evolution has been divided into three potential stages: (i) at small strains (<100%), the crystallinity of PLA increases by orientation-induced crystallization; (ii) at intermediate strains (100%–160%), the crystallinity of deformed PLA slightly decreases due to the breakage of existing crystals under stress accompanying with newly formed voids and cavities; (iii) at high strains (>160%), the increasing number of oriented chains in the amorphous regions promotes the crystallization of PLA. Our study suggests that strain rate and stretching strain play important roles on modulating the crystallization and orientation of amorphous PLA.