Efficient one-pot synthesis of CO2-based functional polycarbonates combining ROCOP and ROMP

Abstract

The incorporation of diverse macromolecular blocks into CO2-based polycarbonates offers a promising approach for tailoring the properties of polycarbonates for special needs. In this work, we report for the first time the synthesis and characterization of an ABA triblock copolymer polycarbonate-b-polyalkenamer-b-polycarbonate in combination of ROCOP and ROMP via a one-pot route from CO2, epoxides and cycloalkenes. Cis-2-butene-1,4-diol as the bifunctional chain transfer agent was used as a “bridge” for the combination of different blocks as well as an effective regulator for the molecular weight of the polymers. In the one-pot reaction, the conversion of cycloalkenes reached 99.9% within 0.5 h, while the conversion of CHO was initially marginal at 0.5% but gradually increased to 99.7% after 24 h. The significant discrepancy in reaction rates between the two processes enables efficient synergistic reactions within the one-pot system. Specifically, hydroxyl-telechelic polyalkenamer is initially formed via ROMP and subsequently acts as an active species for ROCOP when coordinated with the porphyrin Al catalyst. This one-pot strategy provides a unique and simple method for controllably constructing functional polycarbonates with single-modal molecular weight distributions. By integrating the advantages of polyalkenamers and polycarbonates, this approach proves to be a viable solution for addressing the unsatisfactory thermal properties of aliphatic polycarbonates.