Evolution of Copolymers of Epoxides and CO: Catalysts, Monomers, Architectures, and Applications.

The copolymerization of CO and epoxides presents a transformative approach to converting greenhouse gases into aliphatic polycarbonates (CO-PCs), thereby reducing the polymer industry's dependence on fossil resources. Over the past 50 years, a wide array of metallic catalysts, both heterogeneous and homogeneous, have been developed to achieve precise control over polymer selectivity, sequence, regio-, and stereoselectivity. This review details the evolution of metal-based catalysts, with a particular focus on the emergence of organoborane catalysts, and explores how these catalysts effectively address kinetic and thermodynamic challenges in CO/epoxides copolymerization. Advances in the synthesis of CO-PCs with varied sequence and chain architectures through diverse polymerization protocols are examined, alongside the applications of functional CO-PCs produced by incorporating different epoxides. The review also underscores the contributions of computational techniques to our understanding of copolymerization mechanisms and highlights recent advances in the closed-loop chemical recycling of CO-sourced polycarbonates. Finally, the industrialization efforts of CO-PCs are discussed, offering readers a comprehensive understanding of the evolution and future potential of epoxide copolymerization with CO.