New Membrane Materials Based on Crosslinked Poly(ethylene glycols) and Ionic Liquids for Separation of Gas Mixtures Containing CO2

Gas-separation parameters of new network membranes synthesized through the copolymerization of poly(ethylene glycol) dimethacrylate and poly(ethylene glycol) methyl ether methacrylate in the presence of ionic liquids are studied: the permeability, diffusion, and solubility coefficients and the selectivities of gas separation for CO2, O-2, N-2, and H-2. The comparison of filled membranes with an analogous membrane free of ionic liquids shows that an increase in their permeabilities to CO2 is related to an increase in their CO2 solubilities and that improvement of their selectivities for CO2-containing gas pairs is due to the thermodynamic selectivity of separation. The effect of the concentrations of ionic liquids on the gas-transport behavior of network filled membranes is investigated. FTIR studies reveal that ionic liquids in such films occur in two forms: the free form and the form of a "solution" of a network polymer in an ionic liquid. It is found that membranes with the maximum contents of a "solution" of a network copolymer in an ionic liquid possess the maximum permeabilities to CO2 and the maximum selectivities of separation of CO2-containing gas pairs.