A three-dimensional finite strain nonlinear viscoelastic model is developed to study the mechanical behavior of a physically cross-linked Polyampholyte (PA) gel. The time dependent behavior of this gel is due to the ionic interactions of oppositely charged monomers randomly distributed along the chain backbone. In this work, we divide the physical cross-links broadly into weak and strong bonds, depending on their survival and reformation characteristics. Our constitutive model connects the strain dependent bond breaking and reforming kinetics in the microscopic regime to the deformation of the gel at the continuum level. We compare the predictions of our model with uniaxial tension, tensile-relaxation, cyclic, and small strain torsional relaxation tests. The material parameters in our model are obtained using least squares optimization. Our theory agrees well with the experimental behavior of the gel.

建立了三维有限应变非线性粘弹性模型，以研究物理交联的聚两性电解质（PA）凝胶的力学行为。该凝胶的时间依赖性行为是由于沿链主链随机分布的带相反电荷的单体的离子相互作用。在这项工作中，我们将物理交联大致分为弱键和强键，具体取决于它们的生存和重组特征。我们的本构模型将微观状态下应变相关的键断裂和重整动力学与连续水平的凝胶变形联系起来。我们将模型的预测与单轴拉伸，松弛松弛，循环和小应变扭转松弛测试进行比较。我们模型中的材料参数是使用最小二乘法优化获得的。