Thermal decomposition processes in aliphatic polysulfides investigated by mass spectrometry

The thermal degradation of four aliphatic polysulfides (polythiomethylene, polythiotrimethylene, polythioethylene, and polythiohexamethylene) was investigated by direct pyrolysis in the ion soruce of a mass spectrometer (DPMS) operating both in electron impact (E.I.) and chemical ionization (C. I.) modes. Flash‐pyrolysis GCMS was also used in the case of polythiomethylene(polysulfide I) to confirm the DPMS results. The overall evidence indicates that the primary thermal decomposition of these polymers yields cyclic sulfides by an intramolecular exchange process. A β‐CH hydrogen transfer reaction, occurring in parallel with the former process, produces primary pyrolysis compounds with SH end‐groups.