Repurposing poly(monothiocarbonate)s to poly(thioether)s with organic bases

This work reports a unique one-pot/one-step route to rapidly produce poly(thioether)s from poly(monothiocarbonate) (PMTC), a sulfur-containing polymer, using commercially available organic bases. The process started with the degradation of PMTC to a cyclic monothiocarbonate that generated an episulfide via a decarboxylative reaction. Then the episulfide underwent ring-opening polymerization. Organic bases catalyzed the degradation of PMTC and initiated the ring-opening of the generated cyclic monothiocarbonate. This process was successfully expanded to transform several PMTCs to the corresponding poly(thioether)s. The resultant poly(thioether)s exhibited higher thermal decomposition temperatures (up to 311 °C), higher refractive indexes (ca. 1.62) and lower glass transition temperatures (−48 °C) than those of the corresponding PMTCs. This work provides a polymer-to-polymer pathway for repurposing poly(monothiocarbonate)s.