Relative reactivities of epoxide monomers during copolymerization with carbon dioxide

The copolymerization of CO2/propylene oxide (PO)/cyclohexene oxide (CHO) was carried out using a Zn-based heterogeneous catalyst, namely a supported multi-component zinc dicarboxylate. The monomer reactivity ratios of PO (rPO) to CHO (rCHO) were estimated using the Fineman-Ross and Kelen-Tudos graphical methods. The results showed that the rPO values were significantly higher than the corresponding rCHO values in all cases, indicating that the incorporation of CHO into the polymer was kinetically unfavorable. The influence of the reaction temperature and pressure on the monomer reactivity ratios was also discussed. It was found that raising either the reaction temperature or pressure led to an increase in rCHO. In contrast, rPO decreased upon increasing the reaction temperature, but exhibited a small fluctuation upon increasing the reaction pressure.