Experimental study on the radiative ignition of silicones

Abstract

Silicones comprise a wide variety of materials such as fluids, elastomers, resins, and foams. This paper reports the ignitability of some typical silicones under various external radiant heat fluxes. The ignitability of silicones was studied using a cone calorimeter under radiant heat flux levels of 0.5–60 kW m−2. The time to ignition of the silicones was found to be proportional to a power of the incident heat flux that varies from −1.33 to −2.84. For silicone fluids, viscosity (or molecular size) is the key variable in controlling the ignitability. For silicone elastomers, the fillers play an important role in controlling the ignitability, especially at incident heat fluxes lower than 35 kW m−2. The ignitability of silicone resins depends on the chemical structure of the resins: the pure trifunctional resin has the lowest ignitability. The ignitability of the silicone foams having the same density depends on the foam thickness, especially at incident heat fluxes lower than 30 kW m−2. © 1998 John Wiley & Sons, Ltd.