Thermal degradation behavior of rigid and soft polyurethanes based on methylene diphenyl diisocyanate using evolved gas analysis-(gas chromatography)–mass spectrometry

Thermal degradation behavior and its mechanism of rigid and soft polyurethanes (PUs) were investigated by evolved gas analysis-mass spectrometry (EGA-MS) and evolved gas analysis-gas chromatography/mass spectrometry (EGA-GC/MS). Four steps of thermal degradation processes were found in EGA-MS analysis and evolved gases from each thermal zone were analyzed by EGA-GC/MS. From the results, it is suggested that thermal degradation of PUs might be occurred by increased bond strain of polymer chain due to increasing temperature and the sequence of thermal degradation in polymer chain is from hard segment to soft segment through four steps of thermal degradations.