CO2 sorption of elastomer poly(ionic liquid)s with imidazolium cations having different alkyl chains: Structure-morphology-property relationships and thermodynamic modelling by the PC-SAFT equation of state.

In this work related to Carbon Capture and Storage (CCS), the CO 2 sorption capacities of a new family of elastomer poly(ionic liquid)s (PILs) with imidazolium cations having different alkyl chains were studied. These PILs were synthesized by chemical modification of polyepichlorohydrin (polyECH) obtained by living anionic polymerization. PolyECH was quaternized with different 1-alkylimidazoles (alkyl = methyl, n -butyl, and n -hexyl) and followed by anion exchange to obtain three PILs: PIL-Me, PIL-nBu, and PIL-nHex. They were analyzed by NMR (1H, 13C, 2D 1H/13C HSQC, APT 13C) and characterized by SEC, DSC, calorimetry, rheology, and XRD SAXS/WAXS. The influence of the alkyl chain on the PIL CO 2 sorption was studied with a magnetic suspension balance (MSB) at 35 °C and CO 2 pressures varying from 1 to 10 bar. The best results were obtained with PIL having methyl chains (9.60 mg CO 2 /g PIL at 1.1 bar and 159.28 mg CO 2 /g PIL at 10.0 bar at 35 °C). Finally, the CO 2 sorption properties of these PILs were modeled with the PC-SAFT equation of state (EoS). The pure-component parameters were obtained from model regression of the PILs densities calculated by the Bondi's and Van Krevelen's methods. The binary interaction parameters of the systems CO 2 /PIL were optimized with average absolute deviations (AAD) lower than 6.3 % for the three PILs. The PC-SAFT modelling of their sorption properties opens interesting prospects for modelling the CO 2 sorption process for CCS facilities. [Display omitted] • New imidazolium-based PILs with different alkyl chains were obtained from polyECH. • Strong ionic repulsions and low screening effect improved CO 2 sorption. • The best CO 2 sorption was obtained with the methyl chain. • PC-SAFT EoS was used for the first time for modelling CO 2 sorption in PILs. [ABSTRACT FROM AUTHOR]