Abstract:

Silicone rubber （SR） composites were prepared by the incorporation of expandable graphite （EG）， followed by curing with peroxide， and their flame?retardant performance and combustion behavior were investigated. The results indicated that the SR composites containing 5 phr EG reached a UL 94 V?0 rating in the vertical burning tests， and their limited oxygen index value reached 33.0 vol%. The cone calorimeter test resulted demonstrated that the addition of EG suppressed the release of heat and smoke effectively. The mechanism of flame retardant was studied， which indicated that the EG distributed on the materials surface expanded completely and generated a heat insulation layer. Meanwhile， the inner EG expanded to a certain extent and produced a sufficient thermal conductive path to dissipate the heat of materials. Consequently， the SR composites were endowed with excellent flame retardant performance due to the introduction of EG.

Key words: silicone rubber, flame retardant, expandable graphite, heat insulation