Influence of Fe2O3 on smoke suppression and thermal degradation properties in intumescent flame-retardant silicone rubber

This article examines the feasibility of intumescent flame retardant (based on phosphorus acid, melamine, and pentaerythritol) as a flame retardant and Fe2O3 as a smoke suppression agent in silicone rubber (SR) composites. Smoke suppression of Fe2O3 on intumescent flame-retardant SR composites was investigated using smoke density test and cone calorimeter test (CCT). And, the flammability of SR composites was characterized using CCT at an incident heat flux of 50 kW m(-2). The test results further revealed that Fe2O3 could increase smoke suppression efficiency and thermal degradation temperature. Fe2O3 can promote early cross-linking of polymer during decomposition to increase char formation. The silica ash layer integrity governs the efficiency of diffusion barrier that restricts the diffusion of fuels into combustion zone and access of oxygen to the unburned fuels.