标题： 瞬态聚合物网络的应力松弛、动力学和塑性 显示英文标题

标题： Stress relaxation, dynamics and plasticity of transient polymer networks

摘要： 我们提出了一种理论框架，用于处理经历小变形的瞬态聚合物网络，该框架基于网络交联点的断裂和重新形成速率以及不断演化的弹性参考状态。 在该框架中，瞬态网络在微观和宏观尺度上的特性自然统一。 在微观上，交联点的断裂速率受链上局部力的影响。 在宏观上，我们使用经典的橡胶弹性连续体模型来描述变形能的结构，其参考状态根据交联点断裂和形成的时间动态定义。 通过这种方式，可以得到本构关系。 我们研究了该理论在单轴拉伸几何中的三个应用：在施加瞬时阶跃应变后的应力松弛，当施加应变斜坡时在塑性区域的应力过冲及其随后衰减，以及拉伸和释放的循环过程。 我们将模型预测与物理键合热塑性弹性体和玻璃体网络中的应力松弛和应力过冲实验数据进行了比较。 显示英文摘要

摘要： We propose a theoretical framework for dealing with a transient polymer network undergoing small deformations, based on the rate of breaking and re-forming of network crosslinks and the evolving elastic reference state. In this framework, the characteristics of the deformed transient network at microscopic and macroscopic scales are naturally unified. Microscopically, the breakage rate of the crosslinks is affected by the local force acting on the chain. Macroscopically, we use the classical continuum model for rubber elasticity to describe the structure of the deformation energy, whose reference state is defined dynamically according to when crosslinks are broken and formed. With this, the constitutive relation can be obtained. We study three applications of the theory in uniaxial stretching geometry: for the stress relaxation after an instantaneous step strain is imposed, for the stress overshoot and subsequent decay in the plastic regime when a strain ramp is applied, and for the cycle of stretching and release. We compare the model predictions with experimental data on stress relaxation and stress overshoot in physically bonded thermoplastic elastomers and in vitrimer networks.