Development of Rapid Environment Degradable and Recyclable Poly(1,3-propylene glycol oxalate) via Ring-opening Polymerization of Seven-Membered Cyclic Oxalate

As plastic pollution has become increasingly severe, the development of recyclable and rapidly degradable polyesters has significant practical value and significance. In this study, seven-membered cyclic 1,3-propylene glycol oxalate (POx) was successfully synthesized through a two-step polycondensation-depolymerization method using dimethyl oxalate (a low-cost and readily accessible bulk chemical) and bio-based 1,3-propylene glycol as the starting materials. Using Sn(Oct) 2 as the catalyst, high-molecular-weight poly(1,3-propylene oxalate) (PPOx) was efficiently prepared via ring-opening polymerization (ROP) of POx. This ROP demonstrated excellent reactivity, attaining a monomer conversion up to 95% within 10 min, and PPOx had a maximum intrinsic viscosity ( η ) of 1.06 dL/g. Furthermore, the prepared PPOx could be catalytically depolymerized to enable efficient recovery of the POx monomer, with a yield of 60% and a purity of 98%. The degradation performance tests indicated that PPOx exhibited rapid degradation, reaching a degradation rate of up to 99% within 50 days. Owing to the innovative selection of raw materials and the design of a closed-loop process, this study provides a new economical and sustainable strategy for reducing dependence on petroleum resources, offering valuable insights into the development of recyclable and rapidly degradable polyesters.