Influence of different flame retardants on fire behaviour of modified PIR/PUR polymers

The influence of some halogen-free flame retardants (ammonium polyphosphate or ammonium polyphosphate + melamine cyanurate) on fire behaviour of modif ied polyisocyanurate/polyurethane (PIR/PUR) foams, with a constant isocyana te index equal to 200, have been studied by means of a cone calorimeter. Fo ams were prepared from isocyanates modified with adipic acid, in order to o btain amide-modified isocyanurate foams that exhibit better thermal stabili ty performance than polyurethane and lower friability than unmodified polyi socyanurate foams. The results obtained demonstrate that an increasing amou nt of filler causes a slight worsening of physical and mechanical propertie s, On the other hand, the cone calorimeter results show that the presence o f melamine, which causes a rapid decrease of rate of heat release (RHR) and rate of weight loss, considerably improves the fire behaviour of the foams . (C) 2001 Elsevier Science Ltd. All rights reserved.