Synthesis of well-defined and recyclable polyesters from ring opening polymerization of 1,5-dioxepan-2-one catalyzed by a Lewis acid–base pair

Abstract

Conducting the ring opening polymerization (ROP) of 1,5-dioxepan-2-one (DXO) under mild conditions to give well-defined poly(1,5-dioxepan-2-one) (PDXO) remains a challenge. Herein, we reported the ROP of DXO at room temperature by using a Lewis pair of diethylzinc/4-dimethylaminopyridine (ZnEt₂/DMAP) as the catalyst system. The “living” ROP in the presence of ZnEt₂/DMAP showed an obviously improved polymerization rate and can produce linear PDXO with designed molecular weights and well-defined chain ends. Benefiting from the fidelity of “living” terminal groups, a series of block copolymers could be synthesized through the sequential ROP of DXO with δ-valerolactone or L-lactide. Remarkably, the obtained PDXO can be chemically recycled back to its DXO monomer, thus successfully realizing a closed-loop life cycle.