Elastomers are used in a wide range of applications because of their large strain to failure, low density, and tailorable stiffness and toughness. The mechanical behavior of elastomers derives mainly from the entropic elasticity of the underlying network of polymer chains. Elastomers under large deformation experience bonds breaking within the backbone chains that constitute the polymer network. This breaking of chains damages the network, can lead to material failure, and can be utilized as an energy dissipation mechanism. In the case of reversible bonds, broken chains may reform and heal the damage in the network. If the reversible bonds are dynamic, chains constantly break and reform and create a transient network. A fundamental constitutive theory is developed to model the mechanics of these polymer networks. A statistical mechanical derivation is conducted to yield a framework that takes in an arbitrary single-chain model (a Hamiltonian) and outputs the following: the single-chain mechanical response, the breaking and reforming kinetics, the equilibrium distribution of chains in the network, and the partial differential equations governing the deformation-coupled network evolution. This statistical mechanical framework is then brought into the continuum scale by using macroscopic thermodynamic constitutive theory to obtain a constitutive relation for the Cauchy stress. The potential-supplemented freely jointed chain ($u$FJC) model is introduced, and a parametric study of its mechanical response and breaking kinetics is provided. This single-chain model is then implemented within the constitutive framework, which we specialize and apply in two exemplary cases: the mechanical response and irreversible breakdown of a multinetwork elastomer, and the mechanical response of a dual crosslink gel. After providing a parametric study of the general constitutive model, we apply it to a hydrogel with reversible metal-coordination crosslinks. In several cases, we find that the breakdown of the network causes secondary physical mechanisms to become important and inhibit the accuracy of our model. We then discuss these mechanisms and indicate how our existing framework can be adjusted to incorporate them in the future.

弹性体由于其断裂应变大、密度低以及可定制的刚度和韧性而被用于广泛的应用中。弹性体的机械性能主要来自聚合物链底层网络的熵弹性。大变形下的弹性体在构成聚合物网络的主链内发生键断裂。这种链的断裂会损坏网络，导致材料失效，并可用作能量耗散机制。在可逆键的情况下，断裂的链可能会重组并治愈网络中的损坏。如果可逆键是动态的，则链会不断断裂和重组并创建一个瞬态网络。开发了一种基本的本构理论来模拟这些聚合物网络的力学。进行统计力学推导以产生一个框架，该框架采用任意单链模型（哈密顿量）并输出以下内容：单链机械响应、断裂和重整动力学、网络中链的平衡分布、以及控制变形耦合网络演化的偏微分方程。然后通过使用宏观热力学本构理论将该统计力学框架带入连续尺度以获得柯西应力的本构关系。电位补充的自由连接链（网络中链的平衡分布，以及控制变形耦合网络演化的偏微分方程。然后通过使用宏观热力学本构理论将该统计力学框架带入连续尺度以获得柯西应力的本构关系。电位补充的自由连接链（网络中链的平衡分布，以及控制变形耦合网络演化的偏微分方程。然后通过使用宏观热力学本构理论将该统计力学框架带入连续尺度以获得柯西应力的本构关系。电位补充的自由连接链（$你$FJC) 模型，并提供了其力学响应和断裂动力学的参数研究。然后在本构框架内实施该单链模型，我们专门将其应用于两个示例性案例：多网络弹性体的机械响应和不可逆分解，以及双交联凝胶的机械响应。在提供一般本构模型的参数研究后，我们将其应用于具有可逆金属配位交联的水凝胶。在一些情况下，我们发现网络故障导致次要物理机制变得重要并抑制了我们模型的准确性。然后我们讨论这些机制，并指出如何调整我们现有的框架以在未来合并它们。