Experimental investigations of thermal conductivity, thermal degradation and fire resistance of rigid polyurethane foams filled with nano calcite and intumescent flame retardant

Abstract

In this study, nanocalcite and intumescent flame retardant material composed of ammonium polyphosphate and pentaerythritol were filled in rigid polyurethane foams up to 15 % in mass. Effects of the nanocalcite and the intumescent flame retardant additions on the thermal conductivity, thermal degradation and the fire resistance of rigid polyurethane foams with UL 94 horizontal burning test were investigated. Also, the changes of thermal conductivity coefficients of the foams were examined during fifty five days after the production. It was found that although the nanocalcite addition enhances the thermal stability and the thermal conductivity of the foam, it results in decreasing the fire resistance of the rigid foams. However, if the nanocalcite is incorporated with the intumescent flame retardant into the foam, the fire resistance of the foams is enhanced without any significant problems in the thermal degradation and the thermal conductivity. The thermal conductivities of the foams with and without nanocalcite / the intumescent flame retardant increase with time.