Preparation and Properties of Rigid Polyurethane-imide Foams Flame Retarded by Kaolin/APP

PI pre-polymerization method was adopted to synthesize the rigid polyurethane-imide (PUI) foams flame retarded by kaolin(KL) and APP. The effect of content and ratio of KL/APP on the limited oxygen index, smoke density rank, char layer morphology, density and mechanical properties was analyzed. The results show that with the increase of content of KL/APP, the limited oxygen index, density,compressive strength and modulus and surface chalking degree of the rigid polyurethane-imide foams increase. The density exponent values for compression strength and compression modulus are fitted respectively as 1.999 and 1.764; while the smoke density rank of foams decreases with the increasing addition of KL. Moreover, the disadvantage of porous char layer of foams can be improved with the addition of KL/APP.