Zinc adipate/tertiary amine catalytic system: efficient synthesis of high molecular weight poly(propylene carbonate)

Abstract

The copolymerization of carbon dioxide and propylene oxide to generate poly (propylene carbonate) (PPC) were efficiently catalyzed by zinc adipate (ZnAA) in the presence of various tertiary amines as cocatalyst. The influences of temperature, pressure as well as cocatalyst concentration on the copolymerization were studied. The ZnAA/4,4′-methylenebis (N,N-dimethylaniline) composite catalyst shows reasonable high polymer productivity (>280 g polymer/g zinc), high selectivity (>95 %, PPC/cyclic carbonate), especially considerable high molecular weight (Mn > 250 k). Because of the high molecular weight, the as-prepared PPC exhibits apparently improved thermal properties as contrast to the one reported elsewhere previously. Furthermore, the effects of the steric and electronic properties of various tertiary amine derivatives on cocatalytic performance have also been discussed. The experimental results suggest that the tertiary amine cocatalysts with the rigid and bulky aromatic structure are more favorable for the copolymerization.