Polyurethane‐based poly (ionic liquid)s for CO2 removal from natural gas

Abstract

ABSTRACTCarbon dioxide separation from CH4 is important to the environment and natural gas processing. Poly (ionic liquid)s (PILs) based on polyurethane structures are considered as potential materials for CO2 capture. Thus, a series of anionic PILs based on polyurethane were synthesized. The effects of polyol chemical structure and counter‐cations (imidazolium, phosphonium, ammonium, and pyridinium) in CO2 sorption capacity and CO2/CH4 separation performance were evaluated. The synthesized PILs were characterized by NMR, DSC, TGA, dinamical mechanical thermo analysis (DMTA), SEM, and AFM. CO2 sorption, reusability, and CO2/CH4 selectivity were assessed by the pressure‐decay technique. The counter‐cation and polyol chemical structure play an important role in CO2 sorption and CO2/CH4 selectivity. PILs exhibited competitive thermal mechanical properties. Results showed that PILPC‐TBP was the best poly (ionic liquid) for CO2/CH4 separation. Moreover, poly (liquid ionic) base polyol (polycarbonate) with phosphonium (PILPC‐TBP) demonstrated higher CO2 sorption capacity (21.4 mgCO2/g at 303.15 K and 0.08 MPa) as compared to other reported poly (ionic liquids). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47536.