Fire Performance of Curable Silicone-Based Coatings

Polysiloxane elastomers are widely used because of their high thermal stability and low thermal conductivity. In this study, the fire performance of silicone based coatings containing ground calcium carbonate (GCC) are evaluated using a fire testing methodology similar to the "Torch Test" fire testing method. Two kinds of room temperature vulcanized silicone resins containing 50% GCC are used. The two resins, S1 and S2, are based on polydimethylsiloxane (PDMS) and are composed of D [SiO2(CH3)(2)] and T [CH3Si(O-1/2)(3)] structures. The two resins mainly differ in their chain length. It is shown that the performance of the silicone based coating used as thermal barrier are better when the coating is mainly composed of D structures and has high crosslinking density. This is explained by its lower thermal diffusivity at high temperature and by its higher thermal stability.