Flame Retardancy and Smoke Suppression Effect of Zinc Borate-Graphite Intercalation Compound/fe2o3 on Silicone Rubber Foams

To enhance the flame retardancy and smoke suppression of silicone rubber foams (SRFs), a novel flame retardant, zinc borate -graphite intercalation compound (ZB-GIC), was synthesized and used in conjunction with Fe 2 O 3 . The results showed that ZB-GIC markedly improved the flame retardancy and smoke suppression of SRFs, and Fe 2 O 3 significantly improved the smoke suppression of SRFs. ZB-GIC and Fe 2 O 3 had an excellent synergistic effect on flame retardant and smoke suppression. 5 wt% ZB-GIC synergistically with 5 wt% Fe 2 O 3 resulted in SRFs passing the UL -94 V-0 rating, whose limiting oxygen index (LOI) value reached up to 43.7%. Its peak heat release rate (PHRR), total heat release (THR), peak smoke production rate (PSPR), and total smoke production (TSP) decreased by 67.42%, 89.55%, 76.86%, and 91.67% compared to pure SRF. The ZB-GIC produced incombustible gas and a large amount of H 2 O when heated, which reduced the intensity of gas -phase combustion. The ZB filled the interlayer gaps formed after the expansion of GIC to enhance the strength of the char layer, and Fe 2 O 3 further strengthened the char layer. Our work has greatly reduced the fire hazards of SRFs and provided a promising flame retardant for the large-scale production of high-performance SRFs.