Incorporation of ether linkage in CO2/propylene oxide copolymerization by dual catalysis

Carbon dioxide (CO2)/propylene oxide copolymerization using dual catalyst composed of Salen-cobalt(III) complex bearing four quaternary ammonium salts (a highly active poly(propylene carbonate) catalyst) and a double metal cyanide (DMC, a highly active poly(propylene oxide) catalyst) afforded poly(propylene carbonate-co-propylene oxide) through shuttling of the growing polymer chains between the two catalyst sites. Results of H-1 NMR, C-13 NMR, DSC studies supported formation of genuine poly(propylene carbonate-co-propylene oxide), not a mixture of poly(propylene carbonate) and poly(propylene oxide). The carbonate fraction was variable by tuning the ratio of the two catalysts and the CO2 pressure. (c) 2011 Elsevier Ltd. All rights reserved.