Thermal Decomposition of Rigid Urethane Foams

Abstract

Investigation of the thermal degradation of rigid urethane foams by means of TGA, DTA, infrared, and other techniques indicated that rigid foams prepared from a polyoxypropyl ene ether and a polymeric diphenylmethane type polyisocyanate began to decompose at ap proximately 210°C. Loss of weight occurred in two stages of approximately 50% each, oc curring at approximately 250-350°C and 400- 600°C. A similar pattern of decomposition was found for urethane foams based on a chlorinated polyester and the same polyiso cyanate. Addition of a reactive organophos phorous flame retardant to the polyoxypropyl ene ether foam lowered the temperature of initial decomposition to 150-170°C. The weight fraction of char formed at tempera tures above 400°C was increased, however.