Enhanced activity for producing CO2-based polyols enabled by Zn-Co DMC/c-CTA catalytic system

•Different DMC/CTA systems were investigated for CO2/PO copolymerization to produce CO2-based polyols.•A shortened induction period and an enhanced activity was observed with DMC/c-CTA system.•In-depth analysis via characterization and molecular simulation of DMC/CTA systems.•A mechanism for DMC/CTA catalyzed CO2/PO copolymerization was proposed. CO2-based polyols have a unique terminal hydroxyl group structure that makes them suitable for the production of high-performance polyurethane foams. Zn-Co double metal cyanides (DMC) are an important class of catalysts for the copolymerization reaction of CO2 with propylene oxide (PO). In the DMC-catalyzed CO2/PO copolymerization to produce CO2-based polyols, the crucial role of chain transfer agents (CTAs) is emphasized. In this work, a high-performance composite CTA (c-CTA) was successfully developed by investigating various dicarboxylic acids and polypropylene glycol (PPG-400) as CTAs. This system combines the high reaction rate of the DMC/PPG-400 system with the high CO2 insertion rate of the DMC/sebacic acid (SA) system, achieving 2-3 times higher activity than that of single CTA (PPG-400 or SA), reaching 0.5 kg/g. The molecular characteristics of the CO2-based polyols synthesized by different DMC/CTAs systems were analyzed by FTIR and 1H NMR. The reasons for the high catalytic activity of the DMC/c-CTA system were elucidated by analyzing the hydrogen bond distribution in each DMC/CTA systems. Overall, this work provides a theoretical guidance for the development of novel CO2-based materials with high industrial application value. [Display omitted]