Synthesis and degradation of polyurethanes containing phosphorus—Part II: Thermal degradation of poly(butylene phenylphosphonate) and poly(butylene phenylphosphonate) bis(phenylcarbamate)

The principal characteristics and products of thermal degradation of an oligomeric phosphorus containing polyol, poly(butylene phenylphosphonate) (I), and the same compound endcapped with phenyl isocyanate, poly(butylene phenylphosphonate) bis(phenylcarbamate) (II) were studied. (I) and (II) are precursors of a high molecular weight phosphorus containing polyurethane.The products from (I) were butadiene, tetrahydrofuran, dihydrofuran, water, the cyclic ester of phenylphosphonic acid and 1,4-butanediol, phenylphosphonic acid and a linear diester of phenylphosphonic acid and butane diol. The residue at 550°C incorporated pyrophosphonic acid links. All these products were also formed from (II) with the addition of carbon dioxide and aniline.The products and characteristics of the reactions have been accounted for in terms of acceptable processes.