Vol 47, No 6 (2016)

In 2014, chemical fibre demand and consumption in Russia stayed practically at the level of the preceding year. Production (capacity utilization factor 59%) and import rose respectively by 1.9 and 3.5%, export declined by 9.1%. Demand and consumption of viscose staple fibres grew respectively by 21.4 and 29.9% and their import, in consequence, shot up by 25.3%. Demand and consumption of polyester (PE) staple fibres increased a little and production, more noticeably (by 11.5%), import fell slightly and export, quite substantially (by 44.2%). Demand and consumption of polyacrylonitrile (PAN) fibres, primarily as tow procured mostly by import, went up by more than 40%. Progress in polypropylene (PP) staple fibre market was marked. Compared to 2013, demand, consumption, production, and import of polyamide (PA) textile yarns improved with forced reduction of their export by 17%. The results with regard to PE textile yarns were negative in 2014 when their demand, consumption, production, import, and export dropped by 16, 17, 40, 12, and 50%, respectively. On the contrary, demand and consumption of PP textile yarns rose steeply (by 68 and 79%, respectively). Rise of all indicators, except import, to the 3-5% level was noted for PA technical and cord yarns. Import of PE technical and cord yarns is continuing unabated. The year under report was a fiasco in the domestic market of PP film yarns that were being actively introduced into the national economy until recently. The problems of chemical fibre development in Russia are being solved for the most part pretentiously without definite involvement of power structures. The strategy until 2030, even in the case of its realization, is characterized by a twofold drop in the output of this product against the pre-restructuring level and continuation of import by no less than 40% of the total volume of their consumption.

The process of producing a carbon fibre material containing silver based on polyacrylonitrile nanofibres is investigated. It is shown that immobilizing silver during the spinning step is a more efficient method than surface modification of the material.

This paper presents the developed probabilistic spatial model fragments of the structure of polyacrylonitrile fiber, the monomerization composition (condensing components of the polymer matrix), and “Polikon K” – “Polikon K_1a” material. The dynamic contact angle of the investigated material was experimentally determined, and the work of adhesion (1.154 mJ/m²) and wetting (73.855 mJ/m²) of the surface material was calculated. The model of the structure of the “Polikon K_1a” material indicates the most likely point of interaction of copolymer polyacrylic fiber with reactive CH₃– groups of the polymer matrix, namely, the interaction with the C≡N group, by breaking one bond and forming a methylene bridge. The size of the unit cell of the model was estimated: 10.6 × 10.3 × 9.7 Å. The dependence of the torsion angle near the methylene bridge on the concentration of water molecules was investigated.

The effect of the modification parameters on the structure and properties of polyacrylonitrile technical filament (PAN-TF) used to reinforce an epoxide matrix was studied. It was found that treatment of PAN-TF with aqueous solutions of hydrated Cu(II) sulfate could produce modified reinforcing fillers for which the physicomechanical properties tended to increase. The operating properties of composites with the studied PAN-TF were evaluated.

The influence of Fe and Ni nanoparticles added to cation-exchange matrix monomers on the absorption characteristics of the finished materials was studied. It was shown that the developed multi-level polymeric Policon K structures were more branched if an average of 16% of the nanoparticles was added. The absorption characteristics of material with an average of 16% added nanoparticles were increased.

A computer simulation model of the dynamics of elongation of fabric sample and development of breaking of warp in it due to increase in initial random variations in the structure and properties of the warp and weft yarn system is proposed. The model clearly shows that the reasons for the sample breakup are inevitable initial differences (variations) in the properties of the yarns and their arrangement in the fabric, and widening of these differences in the sample elongation process. Interaction between the yarns disperses the arising stress and strain concentrations across the adjacent sections of the fabric and enhances its resistance to deformation, and determines the distinctive nature, mechanism, and dynamics of failure (breaking) of the fabric.

A survey is made of the methods used to monitor parameters of the blending of dissimilar fibers. The methods that are based on visual analysis are time-consuming and are used only under laboratory conditions, since the product is destroyed in the course of the test. In addition, special preparation of the product is necessary to obtain a representative cross section and a satisfactory image of it. A new method is proposed in this article, the method involving an upgrade of existing capacitance-based electronic instruments by providing them with an additional transducer that can evaluate the efficiency with which fiber blends are processed under factory conditions. The coefficient of variation of the anisotropy coefficient for permittivity is determined to show the degree of nonuniformity of products’ compositions. Units based on the use of electromagnetic radiation in the IR and SHF ranges are examined, these instruments making it possible to determine the percentage contents and linear densities of the components of a blend. A new system for automatic monitoring of parameters that characterize the blending of natural and chemical fibers is described. The system is based on a universal attachment for electro-optic transducers that monitor blending parameters on the basis of multiple total-internal-reflection spectroscopy.

The process of developing an adjustable system for controlling the asynchronous electric drive of a weft winder is examined. The system determines the length of the weft fibers and is designed to stabilize the size of the cut-off edges of fabrics at the minimum of the tolerance without adversely affecting product quality. The necessary software is created in a graphical programming language which is realized with the use of the program FlowCode.

We demonstrate the similarities and differences between formation of structural and mechanical properties of polyethylene terephthalate (PET) yarns during drawing and during high-speed spinning (HSS). The orientational drawing process enables a targeted change in structural and mechanical properties of PET yarns. In high-speed spinning, a targeted change in the properties of the yarns to the level attainable in orientational drawing is not possible due to the non-isothermal nature of the process. Studies have shown that the structure formation conditions for the indicated processes need to match better in order to develop an optimized one-step process for obtaining PET textile yarns.

Composites based on novolac phenol—formaldehyde resin acting as a matrix reinforced by discrete carbon fibers were pyrolyzed at various temperatures in the range 400-900°C. Their physicochemical properties were studied. The matrix—carbon-fiber interfacial interaction and the effect of it on the composite mechanical properties were analyzed. It was found that the interfacial interaction was strengthened as the pyrolysis temperature increased. The destruction mechanism of samples treated at various pyrolysis temperatures was also studied.

We have studied the influence of the structural parameters of a composite nonwoven material (obtained by introducing a sorption-active filler with different particle size distributions into the interior and o the surface of a polyacrylonitrile fiber during aerodynamic spinning from a polymer solution) on its basic performance characteristics. We have established that obtaining filled nonwoven materials from thin fibers will allow us to appreciably improve the sorption and physicomechanical properties of fiber webs. We show that it is possible to control the structure of a composite nonwoven material by controlling the aerodynamic spinning parameters, allowing us to obtain materials with performance properties that are optimally suited for use in the finished products, including personal protective equipment, medicine, and the pharmaceutical industry

We present theoretical calculations of the strength of single-ply worsted yarn in the major classification groups used by the TsNIISherst’ scientific industrial company (central wool research institute and pilot plant). We have established and calculated the basic characteristics of worsted yarn in the major classification groups. Results are presented for analytical calculation of the strength of single-ply worsted yarn.

A procedure for performing x-ray structure analyses that allows data on the fine structure of carbon and polyacrylonitrile fibers to be obtained was described. It was shown that carbon fibers were heterogeneous. Their component composition was determined by the preparation conditions and depended on the orientation angle of the coherent scattering regions relative to the filament axis. The structure of crystalline polyacrylonitrile-fiber components included two types of coherent scattering regions, the average sizes of which differed by an order of magnitude. The change in the fine structure of polyacrylonitrile fibers during thermal stabilization was followed.