Polymerization of diphenyl disulfide by the S-S bond cleavage with a Lewis acid. A novel preparation route to poly(p-phenylene sulfide)

Poly (p-phenylene sulfide) (PPS) is efficiently and conveniently produced by a cationic and oxidative polymerization. Diphenyl disulfide is allowed to react with a Lewis acid such as antimony pentachloride at room temperature and is polymerized to PPS. The polymer is isolated as a white powder, whose 1,4 structure is confirmed by IR. Phenylbis(phenylthio)sulfonium ion acts as an active species, which is formed by oxidation of the S-S bond of diphenyl disulfide with the Lewis acid, and is electrophilically substituted on the phenyl ring. The polymerization mechanism is discussed and compared to a model reaction using dimethyl disulfide.