Key words: polymeric membranes, gas separation, 1,2-disubstituted polyacetylenes, CO2 capture, chemical modification of polymers, ionic liquids
This study focuses on the chemical modification of a polymer promising for gas separation membranes to enhance its CO2 selectivity. The possibility of introducing butylimidazolium bromide (BIm+Br-) into the structure of poly(1-trimethylsilyl-1-propyne) (PTMSP) via a two-step process was demonstrated: bromination of the initial polymer with N-bromosuccinimide followed by reaction with a tertiary amine—N-butylimidazole. Supercritical CO2 and CHF3 were used as reaction media, offering advantages over organic solvents, such as non-toxicity, non-flammability, and environmental safety. Depending on the process conditions, the proposed method allows for tuning the BIm+Br- content in the polymer structure. The obtained modified polymers exhibit good film-forming properties, thermal stability, and enhanced resistance to aliphatic, alicyclic, halogenated, and aromatic hydrocarbons. It was found that increasing the BIm+Br- content in the polymer improves the selectivity of CO2/N2 and CO2/CH4 separation while maintaining high gas permeability. These results open new possibilities for designing efficient membrane materials for industrial gas separation applications.
doi:10.1134/S1990793125701040