Synthesis and Characterization of New Eco-Friendly Fire-Retardants Based on Soda-Silicate Glass

Fire-retardants (FRs) are additives used to improve the fire-resistance of combustible materials. New generations of FRs must be effective and eco-friendly. Traditional inorganic FRs are non-hazardous but have limited fire-retardancy. Here, we aim to develop an innovative way to enhance the fire-retardancy of inorganic FRs. We synthesized a new type of FRs, called mATH, whose compositions are similar to soda-silicate glass (xNa 2 O.yK 2 O.zSiO 2 .tAl 2 O 3 ). When applied to unsaturated polyester resin, mATH showed a much better performance than traditional aluminum trihydroxide (ATH). The better performance of mATH originated from its new working mechanism. Dehydrated mATH, as a soda-silicate glass, melts under the heat of the fire, which causes heat sink and produces a molten glass. The molten glass forms a charred insulating layer that prevents oxygen from contacting the interior combustible materials. This phenomenon significantly contributes to the fire-retarding behavior of mATH. Our findings open a new method for developing effective eco-friendly FRs.