Kinetically Enhanced Access to a Dynamic Polyester Platform via Sequence Selective Terpolymerisation of Elemental...

Elemental sulphur, a waste product of the oil refinement process, contains preformed dynamic sulphur-sulphur bonds promising to impart dynamicity onto polymers obtained from this monomer. Yet robust methodologies to access linear polymers with tuneable properties and functionality are rare. Addressing these problems, we here report a rare sequence selective terpolymerisation of elemental sulphur with aromatic thioanhydrides and epoxides under simple lithium alkoxide catalysis yields semi-aromatic poly(ester-alt-S_x). This enables access to terpolymers from a greatly improved range of epoxide comonomers compared to previous methodologies, including industrially relevant, flexible, rigid, functional and natural product-derived variants, allowing tuning of glass transition temperatures across a T_g range of >150 °C. Mechanistic investigations reveal that the insertion of S₈ leads to an unusual rate acceleration via coordinative participation of the polyester links sitting adjacent to the propagating chain end. The thermal stability of the polymers allows for post polymerisation backbone modification via ─S─S─ bond metathesis. After crosslinking, these can be applied as thermally reprocessable and acid degradable adhesives. Our contribution paves the way for the rational buildup of diverse and functional polymer structures from elemental sulphur waste.