A thermodynamically consistent chemo-mechanically coupled large deformation model for polymer oxidation

Abstract

In this work, we present a continuum-level thermodynamically consistent model for high temperature oxidation in polymers, that incorporates the coupling between diffusion, chemical reaction and large deformation behavior of polymers. The specific constitutive forms are derived based on the thermodynamic inequality conditions and the kinetics of the oxidative reactions are considered. Oxidative shrinkage has also been considered in the kinematics as an irreversible effect. Subsequently, the model is implemented in ABAQUS/Standard to analyze numerically the coupled diffusion-reaction behavior of polymers undergoing oxidation. Several numerical simulations are performed to understand the effect of various material parameters on the oxidative response. The model is capable of predicting the heterogeneous oxidation profile within a thick polymer sample. It can also track the growth of oxide layer in the case of a long-term thermo-oxidative aging process. The model can be used to simulate the oxidation process involving complex geometries (as fiber reinforced composites) fairly easily under various ambient conditions.