The flame retardant mechanism and ceramifiable mechanism of silicone rubber were briefly introduced. According to the difference in flame retardant

fillers and char layer structure

silicone rubber was divided into two categories

flame retardant and porcelain. The research progress of flame retardant properties and char formation structure of flame retardant silicone rubber and ceramicizable silicone rubber were reviewed. The analysis shows that the char layer formed during combustion was loose and porous if the silicone rubber was filled with physical or chemical intumescent flame retardant. The char had excellent flame retardant and heat insulation performance

but poor strength. Silicon rubber with non-intumescent flame retardants had relatively dense carbon layer structure

but its surface was not uniform with holes and cracks on it. The flame retardant effect was not good. The ceramic char layer formed by the combustion of the ceramic rubber filled with the porcelain filler was hard and compact. The char layer has excellent refractory durability

but was inferior to the expanded char layer in terms of heat insulation. The char layer has both loose insulation and solid durability

which may be the possible development direction of flame retardant silicone rubber in the future.