Ceramifiable flame-retardant silicone rubber foam for long-term fire resistance and thermal insulating

The development of silicone rubber foam with high mechanical flexibility, thermal insulation, and low cost is of great significance to realize long-term thermal insulation and fireproof but challenging. A strategy that employs intumescent flame retardants to suppress substrate char shrinkage and achieve volume-stable ceramic in silicone rubber foam is proposed. The composites not only maintain mechanical flexibility and excellent fatigue resistance but also exhibit outstanding thermal stability and flame retardancy. Moreover, the foam material can form a volume-stable, dense and hard ceramic residue at high temperatures, thereby exhibiting exceptional thermal insulation upon exposure to ≈1300 °C oxidative environments. The material possessed durable fire resistance, low smoke and toxicity, effectively inhibiting the spread of flames during fires and making it one of the most reliable fireproof plugging foam materials for building applications so far. Besides, the material exhibited an impressive disordered scale-like structure after the calcination test at 800 °C, providing insights into the optimal temperature for ceramicization.