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Poly(1-trimethylsilyl-1-propyne) modified with quaternary ammonium salts is synthesized. The introduction of salts into the polymer structure is carried out using a two-step method consisting in the bromination of the starting polymer followed by the addition of tertiary alkylamines—trimethylamine and triethylamine. The presence of ammonium salts is confirmed by the data of organometallic analysis and IR spectroscopy. X-ray diffraction analysis is used to study the supramolecular structure of the materials obtained. The TGA data indicate their high thermal and thermo-oxidative stability. The permeability, solubility, and diffusion coefficients of the poly(1-trimethylsilyl-1-propyne) samples containing trimethylamine and triethylamine salts for individual CO2, N2, and CH4 gases are determined. An increased ideal selectivity for the separation of gas pairs CO2/N2 and CO2/CH4 in modified poly(1-trimethylsilyl-1-propyne) is achieved owing to the increased selectivity of the dissolution of CO2 in quaternary ammonium salts.

The modification of highly permeable films of brominated 1,2-disubstituted polyacetylene, poly(4-methyl-2-penthyne), via incorporation of in situ formed butylimidazolium bromide is reported for the first time. Principal possibility and efficiency of supercritical CO2 and CHF3 use as reaction media for the corresponding process, namely for quaternization of butylimidazole by brominated polymer are revealed. As a result, we prepared new membrane materials possessing promising properties such as stability toward organic solvents, good mechanical properties and significantly improved CO2-selectivity while maintaining gas permeability at high values. Comparative analysis of the results allowed us to determine content and conditions for the incorporation of butylimidazolium groups optimal for most efficient separation of CO2 from industrial gas mixtures. These results are of interest for the designing of new CO2 selective membranes.

The work is devoted to the chemical modification of a polymer that is promising for the creation of gas separation membranes, aimed at increasing the selectivity with respect to CO2. The introduction of ionic liquids into the structure of poly(1-trimethylsilyl-1-propyne) is realized by a two-step process: bromination of the initial polymer with N-bromosuccinimide and subsequent addition of tertiary amine (N-butylimidazole) to it. Depending on the process conditions, the method allows polymers with different contents of the ionic liquid to be obtained. The obtained polymers show good film-forming properties and thermal stability. Depending on the content of the ionic liquid in the polymer matrix, the resistance to aliphatic alicyclic to the majority of halogenated, as well as aromatic hydrocarbons, increases. With an increase of the ionic liquid content in the polymer, the ideal selectivities of CO2/N2 and CO2/CH4 gas pairs increases while maintaining a high level of permeability.