Ceramifiable Flame-Retarded Silicone Rubber Composites Based on Novel Phosphorus/Nitrogen/Silicon-Containing Flame Retardants

Based on the requirements of fire-resistant performance of silicone rubber (SR) composites, ceramifiable flame-retarded SR composites were prepared in this work. Novel phosphorus/nitrogen/silicon-containing flame retardants were synthesized through the hydrolysis of 3-[2-(2-Aminoethylamino)ethylamino]propyl-trimethoxysilane (P(ANTMS)) and the hydrolysis under phosphoric acid (P(ANTMS-PA)) and phosphorous acid (P(ANTMS-POA)). Ceramifiable SR composites were prepared by using glass powders as sintering aids, and kaolin and sericite as refractory fillers. The sintered residues of the ceramifiable SR composites after burning exhibited a certain strength. The flame retardants were added to the ceramifiable SR composites for improving the flame retardancy, which decreased the peak heat release rate (PHRR) and the total heat release (THR) of the SR composites. The SR composite filled with P(ANTMS-PA) had a low PHRR of 226 kW/m 2 , a low THR of 56 MJ/m 2 and good smoke suppression property. The sintered product of the SR composite filled with P(ANTMS-PA) exhibited the continuous and dense ceramic structure, which could effectively prevent heat transfer and oxygen. The ceramifiable flame-retarded SR composite exhibited excellent ceramifiable property and flame retardancy.