Vol 51, No 4 (2019)

Heightening of interest in manufacture of electrospun nano- and microfibers is associated with the unique properties and characteristics of the produced nonwoven coatings and structures. This article is dedicated to determination of expedient conditions of nanofiber materials production on a Fluidnatek LE-50 equipment using variously designed spinning heads. The distinctive features and specific nature of the nanofibers produced on a coaxial spinning head are described. Experimental investigations of the process of electrospinning of materials from polyvinyl alcohol solution are conducted. The dependence of the flow rate of fiber-forming solution on the emitter voltage and the distance between the electrodes of the equipment for each spinning head was established by statistical processing of the experimental data. The equipment operation conditions that ensure steady occurrence of the process at the maximum solution flow rate are determined.

The potential for fabricating Polycon ion-exchange membranes based on chemical fibers and ionexchange matrices was studied. The fibrous filler was viscose fiber. Sulfonated cation-exchange and polyfunctional mixed-basicity anion-exchange lateral sections were deposited on the fibrous base. The main techniques and process parameters for preparing mosaic membranes were developed. The effect of curing processes on the structural and physicomechanical parameters was studied.

Cationic polymerization of caprolactam was used to produce polyamide-6 modified with electrochemically oxidized graphite. Thermal expansion of oxidized graphite under the conditions for synthesizing the polyamide matrix was confirmed. The experimental functional properties of the developed material improved.

The peculiarities of stochastic estimation of breaking elongation of yarns from various materials are studied. The experimental data do not contradict the hypotheses about application of any of the three common distribution laws. The link between breaking load and elongation is significant in all cases.

Several features of the sorption and proton-desorption mechanisms of heavy metals (M²⁺) from aqueous solutions of acids and native salts (cellulose, chitosan, keratin) by modified biopolymers with acidic (Cell–COOH), salt (^–OOC–W–NH₃⁺), amine (CS–NH₂), and other sorption sites were examined. Sorption isotherms of metal cations from their aqueous salt solutions (pH < 7) by biopolymers were described well in terms of the Langmuir model. The distributions of Cu²⁺, Fe²⁺, Ni²⁺, Zn²⁺, and Cd²⁺ in the heterophasic system H₂O–H₂SO₄–MSO₄–biopolymer were linear functions of the solution acidity in logarithmic coordinates log \( \left({K}_{D{\mathrm{M}}^{2+}}\right) \) vs. pH with tan α ≈ 0.5.

Ultrasonic devices created by the development team are presented, designed to increase the efficiency of various technological processes in laboratory research and the organization of new production. It is shown that the determination of the optimal regimes and conditions of ultrasonic exposure allows the selection of devices based on operating frequencies and intensities of exposure. Providing the necessary conditions for scaling and implementation of optimal regimes and conditions of exposure provides a simple transition from laboratory research to the implementation of processes on an industrial scale when organizing large-scale production.

The sorption-structural properties of fibers, fabrics, and nonwovens are analyzed and the possibility of describing isotherms of water vapor sorption by various equations is examined. It is shown that for approximation of sorption isotherms of various fiber materials use of Zimmerman’s equation for capillary-porous materials in most appropriate. This equation is recommended for use in calculations of drying, extraction, soaking, and other processes of thermohygric treatment of fiber materials.

Results of an experimental study of the process of extracting ammonium nitrate from solutions in a laboratory three-chamber electromembrane device are presented. The nature of the influence of operating parameters on the efficiency of the process is determined. A mathematical model of the electrodialysis process for a unit with a circulating flow pattern is developed. Calculated and experimental data are compared. The proposed mathematical model makes it possible to make a reliable prediction of the content of ammonium nitrate in the concentrate.

The questions of the choice of fabrics for the manufacture of thermal protective clothing are highlighted, the results of a study of the resistance of fireproof and heat-resistant fabrics of various compositions to high temperatures are presented.

We propose combination convective drying of disperse materials based on the kinetic behavior of the process for vegetative feedstock and improvement of the degree of utilization of the energy potential of the heat transfer agent, taking into account energy and exergy thermodynamic analysis methods. We have developed continuous drying equipment for energy-efficient processes using variable thermal treatment.

We give the major approaches to improving processes in leather and pelt production. We describe new methods for processing leather and sheepskin raw material that have been developed at East Siberia State University of Technology and Management. We show their advantages compared with methods used currently.

A matrix model of multiflow, multistage heat-exchange systems each stage of which may possess an arbitrary number of input and output flows, is developed. The solutions of the equations of the model are obtained and analyzed and the reliability and validity of the proposed approach demonstrated. The results may be used to increase the level of validity of calculations of systems of multiflow heat exchangers and to create computersimulators and software programs for optimization of the regimes of technological systems.

A numerical simulation of the air medium inside enterprises involved in the production of chemical fibers demonstrates that the temperature and mobility of the air in the shops may not correspond to the normative requirements. The average period for buildup of pollutant substances in this zone is calculated. Zones with elevated temperature and elevated concentration of pollutant substances are determined. Verification of the data of instrument control and the results of numerical simulation is carried out. The reliability of the model is established and it is shown that the use of the model guarantees that the normative requirements are met.