Poly(ionic liquid)s-based polyurethane blends: effect of polyols structure and ILs counter cations in CO2 sorption performance of PILs physical blends

Carbon dioxide (CO2) capture from natural gas, and further utilization is an essential issue for greenhouse gas reduction. Poly(ionic liquid)s (PILs) assemble ILs unique properties, with those of polymers being versatile materials for CO2 capture from flue gas (CO2/N2) and natural gas (CO2/CH4). PILs based on polyurethanes obtained with different polyols and ILs cations were blended in different proportions aiming to improve PILs CO2 sorption capacity. Two different polyols structures (PC and PG) and ILs counter cations (imidazolium and phosphonium) were tested to evaluate how they influence PILs blends CO2 sorption performance. PILs and PILs blends were characterized by SEC, FTIR, DSC, TGA, DMTA, AFM, and CO2 sorption that were carried out using the pressure-decay technique. PILs blends presented good thermal stability and mechanical properties. PILs blend polyurethane backbones compositions can be tuned aiming to increase CO2 sorption capacity. As far as we know, all obtained PILs blends presented higher CO2 sorption capacity results compared with other Poly(ionic liquid)s reported in the literature. The best CO2 sorption result was obtained for PIL blend with imidazolium (PLIPC95-PG5-BMIM = 116.9 mgCO2/g at 303.15 K and 10 bar).