Thermal decomposition behavior of a thermal protection coating composite with silicone rubber: Experiment and modeling

The lightweight thermal protection coatings becomes increasingly attractive for the protection of the space vehicles from aerodynamic heating. A silicone rubber matrix coating composite with both ablation resistant and thermal insulation constituents was prepared. In order to investigate the pyrolysis behavior, the thermogravimetric analysis was conducted for two constituent materials and coating composites from room temperature to 800℃. After the kinetic parameters had been determined using the model-free and model-fitting approaches, a pyrolysis kinetic model was developed, in which various reaction models of solid-state material were considered. Based on a feasible reaction model, the simulated results exhibited a satisfactory correlation with the experimental data. The thermal decomposition behavior of two constituent materials and the coating composite was studied by combining the microstructural analysis. The thermal decomposition of the coating composite was principally governed by the silicone rubber matrix. The proposed model could be potentially applied to some other thermal loading cases and other polymer matrix composites.