New heat-resistant polyurethanes prepared from hydroxylated cyclotriphosphazenes

The reactions of the dihydroxylated cyclotriphosphazenes, (3,5-dihydroxyphe noxy)(pentaphenoxy)cyclotriphosphazene 1 and 2,2-bis(4-hydroxyphenoxy)- bis [spiro(2',2 "-dioxy-1',1 "-biphenylyl)]cyclotriphosphazene 2 with hexamethy lene 1,6-diisocyanate (HDI) lead to the new cyclotriphosphazene containing polyurethanes 3 and 4, respectively. The condensation polymerization of 1 a nd 1,3-bis(hydroxy)benzene 5, or of 2 and 3,3'-(ethylenedioxy)diphenol 6 in a one step reaction allowed us to synthesize the copolymers poly(1-co-5), and poly(2-co-6). The thermal stability and degradation behavior of 3, 4 an d copolymers were investigated by thermogravimetric analysis in air, and co mpared with that of polyurethanes synthesized from the 5-HDI and 6-HDI reac tions. The evolution of the IR spectra and thermogravimetric analysis curve s of the copolymers vs the cyclotriphosphazene content were studied. (C) 19 99 Elsevier Science Ltd. All rights reserved.