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Eight fractions of polystyrene with linear structure and different molecular weights were prepared by fractional precipitation with methanol from a solution of polystyrene in chloroform. The polystyrene fractions were dissolved in toluene to prepare solutions with different concentrations for dynamic property studies. The dynamic shear modulus and the tangent of the mechanical loss angle for these solutions were measured by the acoustic-resonance method. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract The possibility of preparing modification solutions from sodium naphthalenide wastes and their effect on Teflon adhesion were studied. [ABSTRACT FROM AUTHOR]