End-Group Analysis Of Polyphenylene Sulfide By Thermal Desorption/Pyrolysis-Direct Analysis In Real Time-Mass Spectrometry

Polyphenylene sulfide (PPS) is a promising engineering plastic that is superior in thermal and chemical resistance, and shows high electric conductivity, even under high temperature and humidity conditions. PPS has several different synthetic procedures, which would appear as the difference in the end-group structure, and therefore the structural characterization of PPS is very important. Because PPS is insoluble in solvents at room temperature, their structural characterization is difficult. Recently, we reported that volatile intact oligomers and oligomeric pyrolysis products could be both detected by a thermal desorption/pyrolysis (TDP)/Direct in Real Time (DART)-MS equipped with a programed heating device. In this study, TDP/DART-MS was applied to the characterization of the end-group structure of PPS samples (technical and industrial grades) without pretreatment. Volatile intact oligomers and oligomeric pyrolysis products evolved during heating process could be assigned with the assistance of Kendrick mass defect (KMD) analysis. The intact oligomeric compounds were desorbed at below ca. 400 degrees C and pyrolysis products from the single cleavage of the main chain were evolved at ca. 400 - 500 degrees C. In these temperature range, PPS oligomers having chlorophenyl end groups could be detected. Based on the results, the PPS samples used in this study could be supposed to be synthesized by a Phillips method.