FLAME-RETARDANT POLYURETHANES FROM PHOSPHORUS-CONTAINING ISOCYANATES

Phosphorus-containing polyurethanes are synthesized by reacting phosph orus-containing diisocyanates, bis(4-isocyanatophenoxy) phenyl phosphi ne oxide (BIPPO) and bis(3-isocyanatophenyl) phenyl phosphine oxide (B IPPPO), with various diols. The chemical structures of the obtained mo nomers and polymers are characterized by IR, H-1- and P-31-NMR spectro scopy. Thermal analysis of the phosphorus-containing polyurethanes rev eals that incorporating phosphorus into the polymers increases exother micity during their decomposition. According to these results, the pho sphorus-containing polyurethanes are less thermally stable than conven tional polyurethanes. Char yield and LOI measurements demonstrate that incorporating phosphorus into polyurethanes markedly improves their f lame retardancy. (C) 1997 John Wiley & Sons, Inc.