Lightweight and flame retardant silicone rubber foam prepared by supercritical nitrogen: The influence of flame retardants combined with ceramicizable fillers

Silicone rubber foam has wide application potential because of the lightweight and good mechanical flexibility. Herein, silicone rubber foam with ceramicizable flame retardant coating was prepared by talc, ammonium polyphosphate (APP) and carbon black (CB). The composite foam density was 0.12 g/cm3. Talc had significant melting and flame retardant effects on the ceramicization. The molten crystal structure condensed APP and CB together in turn, and finally formed ceramics with higher bending strength, which improved the flame retardant and ceramic properties. When 30 % talc, 10 % APP and 20 % CB in the coating, the peak heat release rate was 98.7 kW/m2, which was reduced by 300 % compared with the pure silicone rubber coating. After ablation, the compression strength was 900 % higher than that of pure silicone rubber coating because of the formation of ceramicizable coating. This work provides a promising strategy for the preparation of highly efficient flame retardant silicone rubber foam.