PRODUCTS OF NONFLAMING COMBUSTION OF RIGID POLYURETHANE FOAM

Rigid polyurethane foam produced from diphenylmethane diisocyanate and poly(oxytetramethylene) glycol copolymer was decomposed by non-flaming combustion under the temperature and atmosphere conditions simulating the main stages of a fire development. The yields of residue, volatile-condensable products and light gases were affected by the decomposition temperature and the oxygen content in the surrounding atmosphere. The yiels of residue and volatile-condensable products dropped with the temperature increase and increased with the oxygen content drop. The amount of light gases increased with increases in temperature and oxygen content. Among the 50 volatile-condensable products identified by gas chromatography-mass spectrometry were isocyanates, nitriles, amines, nitrogen-containing heterocycles, and aromatic and fused aromatic components. Under these conditions monomers were not identified. The decomposition products may require monitoring owing to their toxic nature.