Assessing the progress of degradation in polyurethanes by chemiluminescence. I. Unstabilised polyurethane films

The thermooxidative and thermal stabilities of polyurethanes synthesized from polyisocyanate and polyester polyol were assessed by chemiluminescence and thermogravimetry. The effect of varying heating rates, synthesis procedures (i.e., with or without a crosslinking catalyst), sample preparations for the measurements, atmospheres (oxygen, nitrogen and their mixtures) and long-term ageing under laboratory conditions were examined and a mechanism of oxidative degradation was proposed based on comparisons of the - separately determined - oxidisability of polyisocyanate and polyester polyol to that of polyurethane.