Thermo-oxidative ageing of elastomers: A modelling approach based on a finite strain theory

Polymers are highly important in industrial applications such as bearings, seals, bonds and coatings. Since these components are used in various areas of engineering, it is obvious that they are exposed to different environmental influences such as mechanical stresses, temperature profiles and chemical or biological substances. Therefore, their properties change over time which leads to limited operating times. In this contribution, the chemical ageing of elastomers within air is examined. A representative example for this phenomenon is the thermo-oxidative ageing of elastomeric bearings in automobiles. After the state of the art is presented and highlighted by scientific data, the experimental equipment necessary for the thermo-oxidative ageing studies is introduced. According to that, experimental data are shown and analysed. From the theoretical point of view, a constitutive approach is formulated by evaluating the Clausius–Planck inequality. The model exhibits a physically-based structure such that a clear identification of all material parameters is possible and meaningful numerical simulations can be shown. The contribution is closed by a summary and outlooks to future trends and objectives.