Modification of Poly(4-Methyl-2-Pentyne) in Supercritical Fluid Medium for Production of CO2-Selective Gas-Separation Membranes

The work is devoted to exploring the possibility of using supercritical fluids as media for modification of polymers offering promise for production of gas-separation membranes with the goal to improve selectivity towards CO2. The possibility is demonstrated for introduction of fragments of quaternary ammonium salts into the structure of poly(4-methyl-2-pentyne) with the help of a two-stage process: bromination of the initial polymer with N-bromosuccinimide followed by the addition of the tertiary amine—N-butylimidazol— conducted in supercritical fluids as a medium. The use of trifluoromethane as the reaction medium provides the highest degree of modification of the brominated polymer with the amine. The polymer produced under the optimized conditions demonstrates a threefold increase of the calculated selectivity of separation of CO2 and N2 in comparison with the initial poly(4-methyl-2-pentyne).