Abstract: Abstract: The silicone foams were prepared using different viscosity α,ω-dihydroxy polysiloxane and vinyl-terminated polydimethylsiloxane as base materials and mica powder as inorganic filler. The effects of siloxane viscosity and inorganic filler content on the microstructure, flame retardancy and thermal stability of silicone foam were investigated by means of scanning electron microscopy, limiting oxygen index, cone calorimetry and thermogravimetric analysis. The results show that the changes in the viscosity of α,ω-dihydroxy polysiloxane and vinyl-terminated polydimethylsiloxane will greatly affect the microstructure and thermal stability of silicone foam. The increase of α,ω-dihydroxy polysiloxane viscosity has a negative effect on the flame retardancy of silicone foam, while the change of vinyl-terminated polydimethylsiloxane viscosity has little effect on its flame retardancy. In addition, the introduction of inorganic fillers can significantly reduce the pore size of silicone foam and greatly enhance its flame retardancy and thermal stability.

Key words: Key words: silicone foam, siloxane viscosity, mica power, microstructure, flame retardancy, thermal stability