论文标题
纠缠聚合物在高压力剪切时的通用缩放行为
Universal Scaling Behaviors of Entangled Polymer Melts at High-stress Shear
论文作者
论文摘要
除了末端流动（区域I）和剪切变薄（区域II）外，我们还发现了高于聚合物高原模量高的壁应力下的两个新流动区域。 III区违反了经验的Cox-Merz规则，其剪切变薄明显较弱，而IV区域IV则表现出意外的剪切增厚。此外，区域II和III之间以及区域III和IV之间的交叉剪切速率分别为Z = m_w/m_e，分别为z^（ - 2.0）和z^（ - 1.2）。我们将剪切变薄的弱化和剪切增厚的出现归因于变形引起的非高斯聚合物拉伸。这些观察结果提供了对高压力剪切物融化的变形行为的第一个实验定量。
In addition to the terminal flow (the region I) and the shear thinning (the region II), we discover two new flow regions in capillary flow at the wall stress higher than the plateau modulus of the polymer. The region III violates the empirical Cox-Merz rule with a significantly weaker shear thinning than the region II, and the region IV exhibits unexpected shear thickening. Moreover, the crossover shear rates between the regions II and III and between the regions III and IV scale with the number of entanglement per chain, Z=M_w/M_e, as Z^(-2.0) and Z^(-1.2) respectively. We attribute the weakening in shear thinning and the emergence of shear thickening to the deformation-induced non-Gaussian stretching of polymers. These observations offer the first experimental quantification of the deformation behaviors of polymer melts at high-stress shear.
