Synthesis of Crosslinked PEG/IL Blend Membrane via One-Pot Thiol–Ene/Epoxy Chemistry

Abstract

Poly(ethylene glycol) (PEG)-based membranes have obtained considerable attentions for CO2 separation for their promising CO2 separation performance and excellent thermal/ chemical resistance. In this work, a one-pot thiol–ene/epoxy reaction was used to prepare crosslinked PEG-based and PEG/ionic liquids (ILs) blend membranes. Four ILs of the same cation [Bmim]+ with different anions ([BF4]−, [PF6] −, [NTf2]−, and [TCM]−) were chosen as the additives. The chemical structure, thermal properties, hydrophilicity, and permeation performance of the resultant membranes were investigated to study the ILs’ effects. An increment in CO2 permeability (~34%) was obtained by optimizing monomer ratios and thus crosslinking network structures. Adding ILs into optimized PEG matrix shows distinct influences in CO2 separation performance depending on the anions’ types, due to the different CO2 affinities and compatibilities with PEG matrix. Among these ILs, [Bmim][NTf2] was found the most effective in enhancing CO2 transport by simultaneously increasing the solubility and diffusivity of CO2.