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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.

This work is devoted to the chemical modification of the polymers of 1,2-disubstituted acetylenes for the creation of gas-separation membranes possessing enhanced stability to aliphatic hydrocarbons and CO2 selectivity. The feasibility of obtaining polyacetylenes containing chlorine atoms in the side substituents of poly(1-trimethylsilyl-1-propyne) (PTMSP) and poly(4-methyl-2-pentyne) (PMP) by radical chlorination with N-chlorosuccinimide has been shown. The reaction has been carried out under mild conditions to minimize the possibility of polymer degradation and other side reactions. The obtained polymers exhibit good mechanical and film-forming properties as well as high thermal stability. Chlorinated PTMSP possesses enhanced stability to alicyclic and aliphatic C5–C12 hydrocarbons. It has been shown that in the case of introduction of chlorine into the structure of PTMSP and PMP, the CO2/N2 and CO2/CH4 selectivities increase, with the high level of permeability being retained.