Thermally stable and high molecular weight poly(propylene carbonate)s from carbon dioxide and propylene oxide

The copolymerization of carbon dioxide and propylene oxide was carried out to afford alternating poly(propylene carbonate) in high yield. Thermal stable and high molecular weight copolymers were successfully obtained by optimizing the reaction conditions. The catalyst used was zinc glutarate supported on a perfluorinated compound containing 7-12 carbon atoms. Copolymerization parameters, such as the ratio of propylene oxide to catalyst, stirring strength and purity of propylene oxide, were studied. The alternating copolymer with a molecular weight of 56100 in a very high yield (126 g polymer per gram of catalyst) was achieved, which is the highest yield ever reported. The thermal and mechanical properties of the alternating PPC copolymer were examined by the means of modulated differential scanning calorimetry (MDSC), thermogravimetric analysis (TGA) and tensile test. MDSC and TGA results showed that the alternating PPC copolymer exhibits an extremely high glass transition temperature (maximum 46.46degreesC) and decomposition temperature (255.8degreesC) when compared to those values reported in literature. Tensile test revealed that thin film of alternating PPC copolymer exhibits superior mechanical strength. (C) 2002 Society of Chemical Industry.