Volume 51, Nº 1 (2019)

A new theory of dynamic deformation of polymer systems in a viscoelastic state provides two points (sites) for measuring rheological characteristics, which significantly increases the amount of information obtained in steady and unsteady state regimes of deformation. Theoretical dependences were obtained that determine the viscoelastic state of a polymer system in the steady state regime of deformation, when the complex viscosity remains constant, but its viscous and elastic components change within its limits.

Effects on polycaproamide structure of a polyfluorinated alcohol immobilized on montmorillonite clay nanoparticles were studied using x-ray structure analysis and broad-line PMR spectroscopy. An exfoliated composite formed and caused the crystal and molecular structures of this heterochain polymer to reorganize. A composite based on the polyfluorinated alcohol changed the mobility of macromolecular chain segments and increased the fraction of planar trans-conformations.

Biocidal cotton material with copper nanoparticles was prepared by treating cloth surface with copper hydroxide in ammonia solution and by coagulation of surface gel and evening of the fiber surface followed by reduction of copper complexes to the atoms and nanoparticles. The experimental structures were characterized by scanning microscopy; energy-dispersive analysis; visible, IR, and Raman spectroscopy; and biocidal studies.

The results of study of rheological and rheokinetic properties of epoxy binders and assessment of the influence of technological factors on the performance properties of samples of winding basalt plastics made for developing industrial technology of production of basalt plastic structural products and heavy-duty fittings having improved performance properties are presented.

The reaction of fluorine-containing latexes with chitosan dissolved in acetic acid and oligoethylenesulfonic acid was studied. Complexes were formed between chitosan and the surfactant used to obtain the latex. The composition of this latex depends on the type of solvent. The anti-adhesive and antimicrobial properties of the fiber materials modified by these compositions were studied.

The stresses and strains of fibers and yarn are investigated, based on the variation of the diameter of the yarn as it is subjected to strain and the effect of compressive forces that arise as a consequence of the spatial arrangement of the fibers in the yarn. It is shown that compressive stresses increase the strain of the fibers and decrease the strength of the yarn. Calculations of the breaking load of the yarn for the simplest and most refined strength theory are given. The mechanism of failure of yarn is demonstrated and numerical estimates of the basic parameters of the stress-strain state of fibers in yarn are obtained.

Solid–state dissolution in N–methylmorpholine N–oxide was used to obtain solutions of mixtures derived from cellulose and various organosilicon additives, namely, tetraethoxysilane, vinyltriethoxysilane, and bis (trimethylsilyl)acetylene. Optical study of the phase composition and morphology of these solutions showed that they are two–phase emulsions with a rather broad size distribution of particles of the dispersed phase. The nature of the flow of the mixed systems in continuous and dynamic deformation when the rheological behavior is monotypic depends to a certain extent on the nature of the organosilicon additive. Dry wet–jet spinning was used to obtain composite fibers. The structure and morphology of these fibers were studied as well as their mechanical and thermal properties. Analysis of the x–ray patterns diffractograms of the cellulose and composite fibers showed that the introduction of organosilicon additives into the cellulose matrix leads to less structural ordering of the cellulose. The mechanical characteristics of the composite fibers show some decrease in the strength and deformation characteristics with an increase in the elastic modulus in comparison with the cellulose fibers. Heat treatment of the cellulose and composite fibers up to 1000°C revealed a significant increase in the mass of carbon residue, whose amount depends on the type of additive.

Low surface-density (10-20 g/m²) nonwoven materials requiring improved hydrophilic properties are used to manufacture hygiene products. Experimental investigations are made of the process of ultrasonic impregnation with an additive and of drying in a field of ultrahigh-frequency currents, of thermoplastic polymeric hygienic nonwoven materials obtained by direct molding. The investigations demonstrated that application of ultrasound is highly effective in improving hydrophilic properties of the material and application of ultrahigh-frequency currents reduces drying time.

The influence of the mechanism of sorption processes on the distribution parameters of the dimensionless value of sorption over a dimensionless chemical potential is analyzed. In the equation of the theory of volume filling of micropores, the rank of the distribution n > 1 characterizes convex isotherms of vapor sorption in microporous adsorbents. The rank of distribution n <1 corresponds to the formation of a homogeneous sorption solution in the supramolecular structure of the swelling polymer. The limitations of the thermal sorption equation are shown, which must be considered when analyzing the microporous structure and properties of fiber-forming polymers.

The application of infrared spectral analysis in the study of fibers is examined. The major absorption intensity peaks of wool and acrylic fiber are determined. An analysis is given for a three-component wool-dyed acrylic fiber-undyed acrylic fiber mixture.

A system for regulating the diameter of optical fiber glass in the process of manufacture is considered. The object possesses pure time delay. In control systems with time delay as in the present case Smith predictors are usually used to reduce the length of the transient process and the control error, though these require construction of a model of the object with time delay. The present article proposes recovery of the coordinate of the controlled quantity prior to time delay in order to then use the coordinate at the inlet to the controller. Finite differences are used to recovery the coordinates, moreover there is no need to construct a model of the object with time delay, that is, maintenance of the precision of the model is not required.