THERMODYNAMICS OF FORMATION OF MODEL FRAGMENTS OF ION-EXCHANGE MEMBRANES BASED ON A COPOLYMER OF STYRENE SULFONIC ACID AND N-VINYLYMIDAZOLE IN THE FRAMEWORK OF COMPUTER SIMULATION

The article presents thermodynamic calculations of model reactions for obtaining composite membrane materials based on a copolymer of styrene sulfonic acid and N-vinylymidazole in the presence of polyvinyl alcohol and oxalic acid. The change in the Gibbs energy (0 K, 1 atm) of the model reactions was calculated using the final single-point energies of the molecules of the starting materials and reaction products obtained from the results of quantum-chemical calcula-tions in the Orca 5.0.3 software package within the framework of the density functional theory using the nonlocal hybrid functional B3LYP, the def2-SVP basis set. The thermodynamic possi-bility of the overall model reaction of condensation of a styrene sulfonic acid and N-vinylymidazole copolymer molecule at the sulfogroup with polyvinyl alcohol in the presence of oxalic acid as a crosslinking agent is shown. The thermodynamically determining step in the complex process is the interaction between the carboxyl group of oxalic acid and the hydroxyl group of the alcohol