Copolymerization of Carbon Dioxide, Propylene Oxide, and Cyclohexene Oxide by an Yttrium-Metal Coordination Catalyst System

摘要

The catalyst system consisting of Y(CF_3CO_2)_3 (I), diethylzinc (II), and glycerine (III) in the solvent of 1,3-dioxolane was found to be very effective to carry out copolymerization of carbon dioxide, propylene oxide (PO), and cyclohexene oxide (CHO). At 353K, 27.2 atm., and a proper combination of the components I to III, the yield and weight-average molecular weight could be as high as of 7948 g/(mol of Y)/h and 2.53 * 10~5, respectively, for a 12 h operation. The IR and NMR spectra indicated that the resulting copolymer was an alternating polyethercarbonate. from the DSC analysis, it is observed that the copolymer resulting from an equal or a higher feed ratio of PO to CHO possessed two glass transition temperatures (T_g), otherwise only one T_g. The temperature at which 10% weight loss occurred (T_(10)) of the resulting polyethercarbonate was also measured in this study. Both T_g and T_(10) were found to locate in a range between those of the copolymers generated from CO_2 and PO, and CO_2 and CHO.