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.

Preparation and characterization of novel flame retardant (aliphatic phosphate)cyclotriphosphazene‐containing polyurethanes

“…Generally, polyurethanes do not exhibit sufficient flame retardancy and are easily burned. Therefore, emphasis on the development of technologies to promote flame retardancy and create flame‐retardant materials has recently increased 2–4. Among these materials, organophosphorus compounds, which generate negligible amounts of toxic gas and smoke, have demonstrated high efficiency as flame retardants for polyurethane.…”

Recent Advances in the Development of Flame-Retardant Polymers

“…Backus et al [150] determined that the thermodynamics of heat combustion of polymers gave little correlation with their flammability, probably because the actual heat that was liberated depended upon the mechanism and rate of combustion. Downing and Anderson [151] have reported that the U.S. Bureau of Mines flame penetration test was unsatisfactory as a general measure of polyurethane foam flammability.…”

The Use of Polymeric Polyisocyanate in Rigid Urethane Foams

“…Studies, conducted in our laboratory, have shown that polymeric polyisocyanate is the most heat stable ingredient in conventional rigid urethane foam systems, and an excellent char former (2). The contribution of typical raw materials to the thermal stability of foam was determined by thermal gravimetric analysis (TGA) as shown in Figure 6 for sucrose based polyether and chlorinated polyester resins, and Figure 7 for polymer polyisocyanate and phosphonate flame retardant.…”