Fibre Chemistry

Mathematical modeling and computed prediction of viscoelastic strain in geotextile needlepunch nonwoven fabrics are discussed. Methods for determining the strain behavior and predicting nonlinearintrinsic creep in these polypropylene materials are proposed. Computerization of the developed methods for confident prediction of strain processes in geotextile needlepunch nonwoven fabrics is discussed

The sorption capacity of carbon-mineral sorbents for Cu(II) ions, methyl orange, and iodine was studied. The optimal carbonization temperature for 100:5, 100:10, and 100:20 mixtures was 600°C, which agreed with experimental IR spectroscopic, elemental analytical, and modern thermal analytical data for carbonized sapropel—bentonite-clay mixtures. The carbon-mineral sorbent prepared by carbonization of 100:5 sapropel—bentonite-clay mixture showed high maximum adsorption for Cu(II) ions, methyl orange, and iodine. The volumes of meso- and micropores of all studied sorbents were determined using molecular probes. Carbon-mineral sorbents prepared by carbonization of sapropel—bentonite-clay mixtures at 600°C in an oxidizing medium were found to be meso-macroporous.

Polymeric catalysts containing Co³⁺ were prepared. Their structures and processing characteristics were studied. The kinetics of catalytic oxidation of a dye solution were determined.

The review considers modern methods for the synthesis of polyacrylonitrile as a precursor for the production of high-strength carbon fiber. Special emphasis was placed on using controlled radical polymerization techniques for the synthesis of a polyacrylonitrile precursor of a given molecular weight in organic solvents.

The article investigates thermodynamic parameters of the dyeing process. The enthalpy change during dyeing with disperse dyes was determined. An equation for the dyeing process with the same conditions for the same type of dyes is proposed.

We have solved the problem of estimating the failure characteristics of a bundle of single yarns for the case when the shapes of their load vs. elongation curves are not identical and are not segments of straight lines. In the calculations, we used a nonstationary arbitrary function of the load vs. elongation dependence. For analysis of the influence of different factors, we used the stochastic computer simulation method. We propose a simulation algorithm we used to perform the calculations for different combinations of the input parameter values. The calculations showed that the deciding influence on the strength utilization of the bundle turns out to be the coefficient of variation for the elongation-at-break for the single yarns.

The flow diagram of a line for the production of bulk nonwoven fabric based on the Bafam carder is presented. The functional diagram of the line is developed, represented, and described on the basis of the flow diagram from the point of view of the presence of electric drives of different mechanisms. The transfer functions of the machine, which is conditionally divided into several zones, are obtained in the course of an analysis of the dynamic behavior of the controlled electrical complex. Using the transfer functions, the transition characteristics as well as the quality of the plant are determined.

An analysis of the process of creating bobbins from glass and basalt threads at high winding rates, which makes it possible to estimate the increase in the mass of the bobbins in the course of taperedmulti-layer cross cone winding, is performed. The parameters of the process of creating bobbins, in which the fixed position of the loops of the thread on the body of the coil at the moment the direction of travel changes, are established.

Structural and morphological evolution of polyacrylonitrile (PAN) samples from starting powder of a ternary copolymer to fibers produced from concentrated solutions of PAN in N-methylmorpholine-N-oxide (NMMO) was studied using x-ray diffraction for the first time. X-ray exposures in transmission and reflection geometries allowed the structures of outer and inner parts of the PAN fibers to be differentiated. It was shown that a shell—core structure formed in the precipitation bath during fiber spinning. A comparison of x-ray diffraction patterns of fibers spun using the NMMO process and industrial samples spun from DMSO and aqueous sodium thiocyanate solutions did not reveal fundamental structural differences.

A method is proposed for imparting antimicrobial activity to phosphorus-containing cellulose and carbon materials entailing the adsorption of antibiotic aminoglycosides such as kanamycin, gentamycin, and amikacin on fibrous cellulose and carbon ion exchangers in acid and salt forms. The interaction of the polymer complexes with the base material was confirmed by IR spectral and differential thermal analysis data. The polymeric composite fiber materials were shown to be nontoxic and have prolonged strong antibiotic activity.

The process of molding tubular matrices of porcine carotid arteries by electroforming from polycaprolactone and a mixture of F-26 fluoroplastic with SKF-26 synthetic fluorine-containing rubber (SFR), which is a vinylidene fluoride−hexafluoropropylene copolymer, is studied. The mechanical properties of the formed matrices in dry and wet state are studied and they are compared with native vessels, the composition of the matrix material is optimized, the molding conditions are set, and the desired vessel wall thickness is chosen. It is shown that the matrices fabricated from fluoroplastics are akin to native vessels in functional properties.

We describe methods for improving the competitiveness of aramid textile materials, based on mathematical modeling and qualitative analysis of their performance/consumer and functional properties.

For successful employment of technology in many fields, it is essential to have materials that possess high electrical conductivity. The electrical conductivity of polymeric materials depends on many factors, primarily on hygroscopicity, structure and chemical constitution, and presence of some substances on its surface. The investigation is conducted on the structure and properties of Armos para-aramid fibre in the context of potentials for subsequent modification for imparting electrical conductivity to it.