Crystalline and Elastomeric Poly(monothiocarbonate)s Prepared from Copolymerization of COS and Achiral Epoxide

The semicrystalline poly­(monothiocarbonate)­s were prepared by the copolymerization of carbonyl sulfide (COS) and ethylene oxide, an achiral epoxide, using a bifunctional chromium­(III) complex as catalyst. The resultant copolymer, possessing perfectly alternating structure, high molecular weight, and narrow polydispersity, has a melting temperature of 128.2 °C, with a melting enthalpy up to 75.44 J/g. Moreover, an ABA triblock copolymer containing the “hard” semicrystalline poly­(ethylene monothiocarbonate) (A) and the “soft” amorphous poly­(propylene monothiocarbonate) (B) is synthesized by stepwise addition of epoxides. The tensile testing demonstrates the triblock copolymer may have the potential as a thermoplastic elastomer.