Synergistic effects of chain dynamics and enantiomeric interaction on the crystallization in PDLA/PLLA mixtures
Synergistic effects of chain dynamics and enantiomeric interaction on the crystallization in PDLA/PLLA mixtures
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DOI：
10.1016/j.polymer.2021.123648
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发表时间：
2021-03-26
期刊：
影响因子：
4.6
通讯作者：
Jiang, Shichun
中科院分区：
文献类型：
--
作者：
Lv, Tongxin;Li, Jingqing;Jiang, Shichun
分子内和分子间的相互作用在聚合物链动力学中起着重要的作用。聚合物的结晶行为和结晶结构受链动力学的影响。含有PLLA和PDLA的对映体自发现以来被认为是PLA结晶的重要成核体。采用不同的溶剂或不添加溶剂制备了含PDLA和立体络合物（SC）晶体的混合物。用DSC表征了立体配合物对均聚物结晶的促进作用和制备的混合物的非等温结晶行为。DSC结果表明，从200℃开始冷却，PDLA/SC混合物中均聚物的结晶温度随着立体配合物含量的增加而升高。摄氏10度/分。结晶温度的升高随着冷却速率的减小而减小，当冷却速率为1 ？C/min或更低。熔炼温度和熔炼时间对促进结晶行为有影响。FTIR结果表明CH3？聚丙交酯对映体之间的相互作用与样品制备中溶解度参数不同的溶剂有关。基于对映体之间的分子相互作用和存在障碍的链动力学，讨论了立体配合物对混合物中PDLA结晶的影响。
Intra- and inter-molecular interactions play an important role in polymer chain dynamics. Polymer crystallization behavior and crystalline structure are affected by the chain dynamics. The enantiomer containing PLLA and PDLA is considered as an important nucleation for PLA crystallization since it was found. The mixtures containing PDLA and stereocomplex (SC) crystal were prepared via different solvents or without any solvent. The effect of the stereocomplex promoted homopolymer crystallization and the non-isothermal crystallization behaviors of the prepared mixtures were characterized by DSC. The DSC results showed that the crystallization temperature of the homopolymer in the PDLA/SC mixtures increases with the stereocomplex contents as cooling from 200 ?C at 10 ?C/min. The increased crystallization temperature reduces with decreasing of cooling rate, and the increasing is even negligible when the cooling rate is 1 ?C/min or lower. The promoted crystallization behavior could be influenced by melting temperature and melting time. FTIR results indicated the CH3?O interactions between the enantiomers of polylactide is related to the solvents with different solubility parameters for sample preparations. The stereocomplex effect on the PDLA crystallization in the mixtures was discussed based on the molecular interactions between enantiomers and chain dynamics in presence of obstacles.