Physics of the Stress Overshoot and Chain Stretch Dynamics of Entangled Polymer Liquids Under Continuous Startup Nonlinear Shear.
Physics of the Stress Overshoot and Chain Stretch Dynamics of Entangled Polymer Liquids Under Continuous Startup Nonlinear Shear.
复制标题
连续启动非线性剪切下缠结聚合物液体的应力过冲和链拉伸动力学物理学。
作者：
K. Schweizer;Shi
我们建立了一个新的理论的瞬态方面的剪切流变纠缠链液体。在一个已建立的管模型本构方程框架内，引入了四个新的物理特征：产生链拉伸的链间夹紧力的张力斑点缩放推导，仿射拉伸变形终止的力不平衡条件，延迟链缩回过程，在失去夹紧力后加速快速变形，以及管直径的分布。非经典的预测的应力-应变曲线刚刚超过超调，主曲线的存在，和分数幂律缩放的超调应变和应力在高剪切速率，所有的实验和模拟结果吻合良好。可测试的新的预测链拉伸动力学。
We construct a new theory for transient aspects of the shear rheology of entangled chain liquids. Within an established tube model constitutive equation framework, four new physical features are introduced: a tension blob scaling derivation of the interchain grip force that generates chain stretch, a force imbalance condition for the termination of affine stretch deformation, a delayed chain retraction process that after loss of grip is accelerated for fast deformations, and a distribution of tube diameters. Nonclassical predictions are made for the stress-strain curve to just beyond the overshoot, the existence of a master curve, and fractional power law scaling of the overshoot strain and stress at high shear rates, all in good agreement with experiment and simulation. Testable new predictions are made for chain stretch dynamics.