Nanolamellar Zn-Ni/Co-Ni Catalysts Introduced by Ball Milling for the Copolymerization of CO2 with Propylene Oxide

Two new kinds of active nanolamellar double metal cyanide complex (DMC) catalysts, Zn-Ni DMC and Co-Ni DMC catalysts, were successfully synthesized by ball milling, which is a clean, green, convenient and rapid synthetic method. Their structures were characterized by FTIR spectrometer, elemental analysis, and SEM images. The results showed that both Zn-Ni DMC and Co-Ni DMC were nanoscale, which improved the catalytic activity by improving its surface area and ensured a better exposure of active sites to the reactants. The alternating copolymerization of CO2 and propylene oxide with the two catalysts showed high catalytic activity, and after 24 h at 4 MPa and 60 degrees C yielded poly(propylene carbonate) (PPC). The PPC from catalysis Zn-Ni DMC has molecular weight (Mn) up to 10,344 g/mol and polydispersity (PDI) of 1.45 with 83.5% carbonate linkages, while from catalysis Co-Ni DMC has molecular weight (Mn: 8478 g/mol) and PDI of 1.44 with 73.7% carbonate linkages. FT-IR and H-1 NMR confirmed product formation.