Investigation of the combustion, thermal and mechanical characteristics of rigid polyurethane foam added with talc and intumescent flame retardant

The aim of this study is to investigate the effects of talc/intumescent flame retardant additions on thermal, burning, and mechanical characteristics of the rigid polyurethane foams. At this purpose, the talc which mainly includes SiO2, MgO and CaO and an intumescent flame retardant which is composed of ammonium polyphosphate and pentaerythritol was incorporated into the foam at various weight loadings. The cone calorimeter tests, UL94 tests, thermogravimetric analyses and thermal conductivity measurements were done for investigation of the thermal and burning characteristics. In general, additions of the talc and the talc/the intumescent flame retardant enhanced the thermal and the fire resistance of the foams. However, the best fire resistance was achieved with a composition which include 10 wt % the intumescent flame retardant and 5 wt % talc. The addition of this composition resulted in 32% reduction in the total heat release value.