Copolymerization of <scp> CO ₂ </scp> and Propylene Oxide Using <scp>ZnGA</scp> / <scp> CaH ₂ </scp> Composite Catalyst for High Carbonate Linkage Content Poly(propylene carbonate)

ABSTRACT The catalytic system represented by zinc glutarate (ZnGA) is at the core of the technology for producing poly(propylene carbonate) from carbon dioxide. In this study, the composite catalyst was prepared with ZnGA as the main catalyst and Lewis base calcium hydride (CaH 2 ) as a cocatalyst for the first time. The result showed that the introduction of Lewis base CaH 2 had a synergistic effect with Lewis acid ZnGA, which effectively inhibited the homopolymerization of propylene oxide (PO) and the formation of cyclic by‐product propylene carbonate, and improved the high content of polyether and propylene carbonate in ZnGA catalytic system under low‐pressure and high‐temperature conditions. At 2.0 MPa and 80°C, the yield of PPC synthesized from the composite catalyst reached 152.5 g PPC/g ZnGA. Compared with the individual ZnGA, the carbonate linkage content in the obtained polymer increased from 86.9% to 93.4%, and the propylene carbonate content decreased from 22.5% to 11.1%.