The development of a constitutive representation for predicting the durability of filled rubbers upon aggressive environmental conditions is crucial for numerous technical examples but still remains largely an open issue. This paper presents a constitutive model for the prediction of thermal aging effects on the inelastic response of filled rubbers. A network alteration theory is proposed for the thermally driven network degradation by considering a collection of chemical and physical changes occurring inside the rubber-filler material system. The network decomposition considers scission-rebound mechanisms of links (between filler aggregates and between elastically active cross-linked chains) and changes in movements of the free chains superimposed into the (newly born and original) chemically linked network. The material kinetics is designed using multi-step (physical) stress relaxation experiments performed at room temperature on a sulfur-vulcanized styrene–butadiene rubber containing different amounts of carbon-black fillers, and previously submitted to an accelerated chemical stress relaxation procedure, i.e. aging at constant stretch for various temperatures and exposure times. The time–temperature equivalence principle is used to construct master curves of the alteration kinetics for both the cross-linked chains and the superimposed free chains. The amplified effect of the fillers is also considered in our network decomposition to account for the cross-linked chains/fillers interactions and the free chains/fillers interactions. The capabilities of the proposed network alteration based constitutive model to describe and predict the material response evolution in terms of stiffening, hysteresis area increase and physical relaxation increase are shown. The chemically induced “plastic-like” deformation and stress relaxation are predicted using the developed model. The results show the importance of the inelastic effects on the prediction of long-term material response due to thermally activated degradation. From an applicative point of view, the model makes possible to estimate the operational life of pre-strained rubber mechanical components with respect to loss of pressure and flexibility.

用于预测填充橡胶在恶劣环境条件下的耐久性的本构表示的开发对于许多技术示例至关重要，但仍然在很大程度上仍然是一个悬而未决的问题。本文提出了一种用于预测热老化对填充橡胶非弹性响应的影响的本构模型。通过考虑橡胶-填料材料系统内部发生的一系列化学和物理变化，提出了一种用于热驱动网络退化的网络改变理论。网络分解考虑了链接（填料聚集体之间和弹性活性交联链之间）的断裂-回弹机制以及叠加到（新生和原始）化学连接网络中的自由链的运动变化。材料动力学是使用在室温下对含有不同量炭黑填料的硫磺硫化丁苯橡胶进行的多步（物理）应力松弛实验设计的，并预先进行加速化学应力松弛程序，即老化在不同温度和暴露时间的恒定拉伸。时间-温度等效原理用于构建交联链和叠加自由链的变化动力学主曲线。在我们的网络分解中也考虑了填料的放大效应，以解释交联链/填料相互作用和自由链/填料相互作用。显示了所提出的基于网络变化的本构模型在硬化、滞后面积增加和物理松弛增加方面描述和预测材料响应演变的能力。使用开发的模型预测化学诱导的“类塑性”变形和应力松弛。结果表明，由于热激活降解，非弹性效应对预测长期材料响应的重要性。从应用的角度来看，该模型可以估计预应变橡胶机械部件在压力和柔韧性损失方面的使用寿命。使用开发的模型预测化学诱导的“类塑性”变形和应力松弛。结果表明，由于热激活降解，非弹性效应对预测长期材料响应的重要性。从应用的角度来看，该模型可以估计预应变橡胶机械部件在压力和柔韧性损失方面的使用寿命。使用开发的模型预测化学诱导的“类塑性”变形和应力松弛。结果表明，由于热激活降解，非弹性效应对预测长期材料响应的重要性。从应用的角度来看，该模型可以估计预应变橡胶机械部件在压力和柔韧性损失方面的使用寿命。