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Shish-Kebab Crystallites Initiated by Shear Fracture in Bulk Polymers
Macromolecules ( IF 5.5 ) Pub Date : 2018-01-09 00:00:00 , DOI: 10.1021/acs.macromol.7b02357
Yijing Nie 1, 2 , Yunfeng Zhao 3 , Go Matsuba 3 , Wenbing Hu 1
Affiliation  

The study of shear-induced polymer crystallization has so far overlooked heterogeneous crystal nucleation of shish-kebab crystallites, which can be initiated by the stretched local polymer chains in the sporadic events of shear fracture upon sudden startup or cessation of polymer shear flow or in the memory of these events. We performed dynamic Monte Carlo simulations of a binary blend of short and long polymers and investigated the formation process of shish-kebab crystallites in a driven field with Poiseuille-flow-like gradient forces presumably generated around the shear layer of melt fracture. The results demonstrated the synergetic coil-extension and segregation behaviors of long-chain fractions upon precursor formation, which lead to a discontinuous crystalline structure along the shish. We found that the shear fracture hypothesis can reconcile several controversial experimental arguments on the precursor formation of shish-kebab crystallites in shear-induced polymer crystallization.

中文翻译:

块状聚合物中的剪切断裂引发的Shish-Kebab微晶

迄今为止,对剪切诱导的聚合物结晶的研究忽视了烤肉串微晶的异质成核现象,这可以通过在突然启动或停止聚合物剪切流或在剪切过程中发生的剪切断裂的零星事件中,由拉伸的局部聚合物链引发。这些事件的记忆。我们对短聚合物和长聚合物的二元混合物进行了动态蒙特卡洛模拟,并研究了在驱动场中羊肉串晶体的形成过程,该场中可能在熔体破裂的剪切层周围产生了类似Poiseuille流的梯度力。结果表明,前体形成后长链级分的协同线圈延伸和偏析行为,导致沿光泽的不连续晶体结构。
更新日期:2018-01-09
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