Thermodynamic and adsorption properties of semiinterpenetrating polymer networks based on polybenzimidazoles and polyaminoimide resin

Thermodynamic characteristics of adsorption of organic compounds on semiinterpenetrating networks based on polybenzimidazoles and polyaminoimide resin with different compositions were studied at small coverages using inverse gas chromatography. The following characteristics were determined: adsorption equilibrium constants (specific retention volumes) of substances of different classes (n-alkanes, aromatic hydrocarbons, ethers, ketones, alcohols, and nitrogen- and halogen-containing compounds), appropriate changes in differential molar internal energy and Helmholtz potential, and changes in standard molar entropy of the sorbates. The contributions of the molecular fragments to the heat of adsorption were calculated. The adsorption properties of the semiinterpenetrating networks based on polybenzimidazoles and polyaminoimide resin differ from those of the starting polymeric materials and their physical mixtures with the similar composition. Unlike graphitized thermal carbon black (nonspecific adsorbent), the network and starting materials manifest the specific properties (electron-donating and electron-accepting). The difference in the thermodynamic characteristics of adsorption on the semiinterpenetrating polymeric networks with different compositions is determined by the size and geometry of interphase regions.