Fire performance of poly(dimethyl siloxane) composites evaluated by cone calorimetry

Flame retardant behaviour of polydimethylsiloxane (PDMS) foam composites has been investigated by thermogravimetry and cone calorimetry to determine the effect of FR on fire performance. PDMS composites were prepared with FR magnesium hydroxide and zinc borate acting in the condensed and gaseous phase. The hydrated fire retardants evolve water that cools the substrate. Magnesium oxide is retained in the composite insulating and limiting the diffusion of combustible volatiles. The thermal stability of PDMS decreased with kaolin, but increased with the addition of fire retardants. The heat release rate of the composites exhibited two peaks indicative of char formation and breakdown, attributed to fragmentation/cracks exposing increased surface area to the incident heat flux.