Vol 49, No 6 (2018)

Modification of polyacrylonitrile fiber by ethylenediamine in aqueous solution and the vapor phase was investigated. The optimum process conditions were determined. The process was found to be significantly enhanced if the gaseous amine was used rather than its aqueous solution. FTIR spectra confirmed the structure of polymer fiber produced under these conditions.

Parameters for modification of basalt yarns by organosilanes A-187 and A-174 were chosen. The modified basalt yarns typically had improved physicomechanical and adhesive properties as compared with the starting yarns. Modified basalt yarns produced by the selected method were demonstrated to improve the operating properties of composites.

The effect of the introduction of oxidized multiwall carbon nanotubes (MWCNTs) on the process of suspension polymerization of acrylonitrile is investigated. Some physical characteristics of the obtained PAN/MWCNT composite powders at different ratios of the components, as well as their solutions in dimethylsulfoxide, were determined. The optimal polymerization conditions (in terms of the yield and operational properties of the polymer product) are proposed.

The article is devoted to the use of optical methods in the study of the properties of fibrous materials. Based on the results of an analytic investigation of the transit of a narrow beam of infrared radiation through a fibrous material we are able to determine the optimal location from the point of view of the maximum sensitivity of the source and detector of the radiation of an optoelectronic transducer where an optical sensor is used in the control system. The relationships and practical calculations obtained make it possible to quantitatively estimate the values of the propagation of radiant energy, and this may serve as a basis for structural and energy calculations of the parameters of an infrared optoelectronic transducer.

Polyetheretherketones (PEEKs) of different molecular masses were synthesized via high-temperature polycondensation using nucleophilic substitution by varying the excess of 4,42-difluorobenzophenone. The dependences of the thermal and physicomechanical properties of the PEEKs on the intrinsic viscosity were studied. The conditions for synthesizing PEEKs that produced a polymer powder with the property set needed for high-quality 3D printing using SLS technology were determined.

Fusible and soluble polyazomethines containing triarylmethane fragments in the main chain were synthesized. IR and NMR spectroscopy established the structures of the obtained polymers. It was shown that polyazomethine fibers could be prepared from their melts. It was found that the obtained fibers were birefringent, indicating that the macromolecules were highly oriented during their spinning. The polyazomethine fibers had increased strength and elasticity modulus. It was found that annealing the polyazomethine fibers strengthened them. The reason for the increased mechanical properties of the fibers was post-polycondensation that was associated with a change of molecular mass of the starting polymer.

Interfacial regions in polypropylene/globular-nanocarbon composites were shown to have a multilayered structure consisting of layers of polymer adsorbed to the surface of nanofiller particles (particle aggregates). Increasing the level of polymer-matrix—nanofiller-surface interfacial adhesion decreased the number of such layers. As expected, the interfacial-region parameters were determined by characteristics of both the nanofiller and polymer matrix.

Experimental X-ray diffraction analysis procedures and calculation algorithms are proposed for determining the degree of crystallinity of flax fibres of varied purity and their cellulose component from the integral values of diffraction by the crystallite regions of the analysis sample and the reference standard, which are normalized, taking account of the scattering mass of the preparations. The possibility of determination of the mass cellulose content in flax fibres by X-ray analysis, which dispenses with the need for labor and time consuming chemical analyses, is substantiated.

A mathematical description of the process of heat transport under single-valued conditions for a closed two-phase thermosiphon that may be used to transmit heat in different industrial processes and in different industries is created. By extending the mathematical model it may be used in the design of thermosiphons for the development of energy-conserving structures as a way of increasing energy and economic efficiency in the production of edible phosphates.

The problem of scanning the form of raw material in the course of pattern cutting in the fabrication of planar parts is considered. A machine vision system is used to solve the problem. In the context of the problem questions of calibration of the system and the elimination of optical distortions become critical with the use of such technologies. Different methods of calibration of the cameras of computer vision systems are presented. It is proposed that the use of test objects be rejected in favor of marked bands applied along the extreme edges of the working region of the pattern complex as well as the use of an algorithm for searching for marked bands on the images produced by the system.

The possibility of using fuzzy cognitive maps in the operation of the production line for the fabrication of space-filling nonwoven fabric is considered. A technique of cognitive simulation of complex dynamical objects is determined and a list of concepts that characterize the state of the flow line is presented. Modernization of the electrotechnical complex with the use of a multi-motor electric drive is proposed based on an analysis and simulation of a cognitive map. A dependence of the quality of the weave produced by a combing machine on the speed and linear density of the fibers is found. The problem of impacts against the machine case when the direction of travel of the carriages changes is solved through the use of separate electric motors that assure smooth and independent control.

Data are given on aromatic copolyether ether ketones obtained from aromatic diols, namely, hydroquinone and diphenylolpropane (Bisphenol A). The copolyethers were synthesized by high–temperature copolycondensation of the corresponding diols with 4,4'–difluorobenzophenol. The dependence of the rheological and thermochemical properties of the polymer samples on the mole ratio of the diphenols was studied for a broad range of monomer concentrations. Enhanced heat resistance along with decreased intrinsic viscosity and glassy point temperature were found for copolyether ether ketones with a greater content of hydroquinone.

The affiliation of the authors V. Reimer and T. Gries should read:

Textile Institute of Rhine-Westphalian Technical University of Aachen (RWTH Aachen), Aachen, Germany.