Thermal stability of cyanate ester modified silicone rubber as matrix of heat-resistant composite coatings

Heat-resistant composites are widely used as high-temperature engineering materials. Polymer materials are often used as the matrix of the composites due to their good processability and adhesion to different substrates. In order to improve the thermal stability of silicone rubber (SR) matrix, CE/SR composites were prepared from cyanate ester (CE) prepolymer and silicone. The chemical structure, morphology and thermal stability of the obtained CE/SR composites were analyzed by Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis (TGA). SEM images of the cross sections of CE/SR show that a two-phase microstructure consisting of continuous SR and dispersed CE can be formed by successively curing of silicone and CE prepolymer. TGA analysis results show that CE modified SR has higher heat resistance than SR, and the thermal stability of CE/SR composites is better than that of pure SR and pure CE in the temperature range of 300-500 degrees C. The composite of KL and CE/SR was prepared to further improve the heat resistance.