Primitive chain network simulations for the interrupted shear response of entangled polymeric liquids
Primitive chain network simulations for the interrupted shear response of entangled polymeric liquids
复制标题
缠结聚合物液体断续剪切响应的原始链网络模拟
DOI：
10.1039/d0sm00654h
复制
发表时间：
2020
期刊：
影响因子：
3.4
通讯作者：
and Takashi Uneyama
中科院分区：
文献类型：
--
作者：
Yuichi Masubuchi;Yuya Doi;and Takashi Uneyama
断续剪切流下的非线性粘弹性响应是缠结聚合物的有趣特征之一。特别是，在一些研究中，关于纠缠网络的恢复，讨论了恢复剪切中的应力超调。在这项研究中，我们进行了多链滑移模拟来观察缠结聚合物熔体的分子结构。在用文献数据确认我们的模拟的合理再现性后，我们按照解耦近似分析了分子特征。我们合理地发现，即使在恢复剪切下，段方向也主导着应力超调，而段拉伸和缠结密度的贡献较小。我们将应力超调恢复的缓解函数定义为休息时间的函数，并将其与初始剪切后分子量的弛豫进行比较。结果，我们发现应力超调的缓解与纠缠密度的松弛相一致。
The non-linear viscoelastic response under interrupted shear flows is one of the interesting characteristics of entangled polymers. In particular, the stress overshoot in the resumed shear has been discussed concerning the recovery of the entanglement network in some studies. In this study, we performed multichain slip-link simulations to observe the molecular structure of an entangled polymer melt. After confirming the reasonable reproducibility of our simulation with the literature data, we analyzed the molecular characteristics following the decoupling approximation. We reasonably found that the segment orientation dominates the stress overshoot even under the resumed shear with minor contributions from the segment stretch and entanglement density. We defined the mitigation function for the recovery of the stress overshoot as a function of the rest time and compared it with the relaxation of the molecular quantities after the initial shear. As a result, we have found that the mitigation of the stress overshoot coincides with the relaxation of entanglement density.