THERMAL-DEGRADATION OF POLY(PHENYLENE SULFIDE) AS MONITORED BY PYROLYSIS GC/MS

The thermal degradation of two commercial samples of poly(phenylene sulfide) (PPS) has been studied over a range of pyrolytic temperatures using flash pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). At the lower pyrolysis temperatures (up to about 550 degrees C) the major volatile pyrolysis products detected were the cyclic tetrameter and the linear trimers and dimers, formed as a result of random scission followed by depolymerization and cyclization. Under more severe pyrolysis conditions (550 degrees-800 degrees C) the concentrations of the oligomers start to decrease and those of benzene and benzenethiol increase. In addition, at these intermediate temperatures of 550-650 degrees C it appears that rearrangement reactions are occurring followed by cyclization to give rise to benzo-thiophenes and some naphtho-thiophenes. The predominant degradation process, however, appears to be random chain scission followed by cyclization at the lower temperatures and depolymerization at the higher temperatures.