One-Step Conversion of Bisphenol A Polycarbonate into Aliphatic Polycarbonate Polyols for Recyclable Polyurethane Production.

The growing accumulation of plastic waste emphasizes the pressing need for sustainable recycling technologies. In this study, we present a one-step conversion of bisphenol A- based polycarbonate (BPA-PC) waste into aliphatic polycarbonate (APC) polyols using diols with varying chain lengths. The resulting APC polyols were subsequently utilized as soft segments in combination with 4,4'-methylene diphenyl diisocyanate (MDI) in the production of thermoplastic polyurethanes (TPUs). These TPUs exhibited excellent mechanical properties, with a maximum tensile strength of 58 MPa and elongation at break of 397%, as well as robust hydrolytic stability, maintaining performance even after prolonged water exposure. Notably, the APC-based TPUs exhibited excellent recyclability through organocatalytic depolymerization, which facilitated the simultaneous hydrolysis of both urethane and carbonate bonds. This process yielded the selective formation of 4,4'-methylenedianiline (MDA), an industrial precursor to MDI, and 1,4-butanediol (1,4-BD) with remarkably high yields of 96% and 95%, respectively. This work provides valuable insights into designing closed-loop recyclable polymers by upcycling plastic waste via a straightforward process. Additionally, it offers a practical and impactful solution for the end-of-life management of upcycled polyurethane products, thereby contributing to a circular plastic economy.