Stress and Pressure Dependent Thermo-Oxidation Response of Poly (Bis)Maleimide Resins

摘要

Thermo-oxidative degradation in high temperature resins can be accelerated by increased oxygen pressure and the stress in the material. While the oxygen pressure increases the adsorbed oxygen concentration on the surface, stress affects the diffusivity. We describe a comprehensive sorption, oxidation (diffusion-reaction) and stress evolution model for polymers and composites and apply the model for oxidation growth prediction in (bis)maleimide resins. The model framework uses a pressure-dependent boundary sorption model and stress-dependent diffusion model. Evolution of thermo-oxidative degradation in a commercially available resin and composite system is experimentally characterized and the results are used for identifying model parameters and model validation. The key contributions are the characterization and validation of a single parameter for stress-diffusion coupling. The parameter value is identified at one stress-level and the oxidation behavior at higher level is simulated. The results show that the effect of substrate stress and the oxygen pressure can be effectively simulated using the developed framework.