S. F. Grebennikov

Prediction of the change in density in systematic series of fibre-forming polymers

The density of aliphatic polyamides is determined by the concentration of amido groups and additively increases in systematic order. The packing coefficient of aliphatic polyamides determined by the ratioρa/ρc increases with an increase in the concentration of amido groups. The density of cellulose acetateis determined by the concentration of acetate groups and decreases additively in systematic order. The calculation with the group contribution method can be used to predict the density of crystallites of fibreforming polymers. but this method only gives approximate results for amorphous regions.

Predicting the Properties of Polymeric Materials Exposed to Moisture and Thermal Loading

Several properties of polymeric materials in a moist medium (crystallinity, glass point, volumetric deformation, thermodynamic properties) are mathematically modeled on the basis of the thermal equation for the sorption of water.

Thermodynamic Features of Mixing of Chitosan with Polyvinyl Alcohol and Polyethylene Oxide

Chitosan-polyvinyl alcohol and chitosan-polyethylene oxide systems were examined by water vapor sorption method. Based on the experimental data, the Gibbs energy, entropy, and enthalpy of the polymer mixing were calculated.

Change in the melting points and glass transition temperatures in systematic series of fibre-forming polymers

It was shown that the physicomechanical properties of fibre-forming polymers of systematically varied molecular composition vary regularly as a function of the equivalent concentration of functional groups. The constants in equations describing the change in the temperature indexes as a function of the concentration of functional groups were determined. The reliability of the values calculated and used was assessed.

Structural Aspects of the Thermodynamics and Mechanics of Interaction Between Aramid Fibers and Water

We have used sorption and physicomechanical methods to study the effect of water in the vapor and liquid phases on the supermolecular structure of partially crystalline and liquid-crystalline polymer systems.

Electrophysical Properties of Carbon Fibres Decorated with Bismuth and Indium

The process of activated and graphitized carbon fibre modification with bismuth and indium nanoand micro-particles is studied. The properties of the carbon fibres before and after modification are analyzed.

Kinetics of Antibiotic Exchange on Fibrous Ion Exchangers

Sorption modes were determined and diffusion coefficients were calculated for several antibiotics during ion exchange on polypropylene and polycaproamide fibrous ion exchangers. It was shown that the diffusion coefficients were largely determined by the ionic strength of the sorbent and sorbate functional groups. The desorption kinetics of the antibiotics enabled their contents in the fibers and rates of desorption to be predicted mathematically. This allowed the concentration of the active ingredient and the duration of antimicrobial activity to be controlled.

Sorption and diffusion of water in Arselon and Arselon-S polyoxadiazole yarns

Sorption properties of Arselon and Arselon-S polyoxadiazole fibers and yarns were studied. Regular trends in interaction of polyoxadiazoles with water vapor were revealed. The effective coefficients of internal diffusion of water into polyoxadiazole fibers (yarns) were calculated.

Alteration of the hygroscopic properties in systematic (homologous) series of fibre-forming polymers

It was shown that the hygroscopicity and characteristic energy of sorption of water vapor by fibre-forming polymers with a systematically varied molecular composition change nonlinearly with an increase in the concentration of functional groups. Equations are proposed for calculating the sorption isotherms as a function of the molecular structure (concentration of functional groups) and supermolecular structure (degree of crystallinity) of the polymer.