Abstract

In order to enhance the ablation resistance in prolonged high-temperature conditions and concurrently elevate the mechanical property and heat resistance of epoxy resins, a "rigid-flexible" cocross-linked epoxy resin was synthesized through the copolymerization of silicone and bismaleimide. With the addition of 20 phr of bismaleimide (B7D3) and 50 phr of silicone, EP-B7D3@50P shows excellent ablation resistance and heat resistance due to the rigid bismaleimide and flexible ceramizable silicone network. The glass transition temperature was increased by 16.4 °C compared to epoxy resin. Most significantly, the mass and linear ablation rate dropped by 77.6% and 85.7%, respectively, due to silicone's exceptional carbon-forming capabilities, lower pyrolysis rates, and vapor deposition effects. Furthermore, the rigid bismaleimide cross-linking networks not only improve the modulus but also compensate for the reduction in mechanical properties caused by the silicone. This work provides an advanced approach for the preparation of thermally protective materials with high strength and heat resistance.