A theoretical study of structure-solubility correlations of carbon dioxide in polymers containing ether and carbonyl groups

This work involves a theoretical study to investigate the effects of the structure on CO2 sorption in polymers, where poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), poly(vinyl acetate) (PVAc), poly(ethylene carbonate) (PEC) and poly(propylene carbonate) (PPC) were examined. In the theoretical approach, the multi-site semiflexible chain model and the renormalized technique of electrostatic potentials were incorporated into the polymer reference interaction site model (PRISM). To test the theory, molecular dynamic simulations were performed using the TraPPE-UA force field. The theoretically calculated reduced X-ray scattering intensities and intermolecular correlation functions of these five polymers are found to be in qualitative agreement with the corresponding molecular simulation data. The theory was then employed to investigate the distribution functions between CO2 and different sites of the polymers with consideration of the Lennard-Jones, potential of mean force, and columbic contributions. Based on the detailed structure characteristics of CO2 in contact with different groups, the CO2 coordination molecular numbers were obtained and their sorption intensities analyzed. Finally, the sorption isotherms of CO2 in these five polymers were calculated. The results for PEO, PPO and PVAc are close to the available experimental curves, and the trend of CO2 solubility is PPC > PEC > PVAc similar to PPO > PEO.