Preparation of a polyacrylonitrile fiber from a mixture of an acrylonitrile-methyl methacrylate copolymer and a polyurethane

Conclusions The most stable solutions of mixtures of polyacrylonitrile with polyurethane (containing the heterocyclic triazine ring in the main chain) with an optimum size of the disperse phase particles were obtained at a component ratio of 95:5.Introduction of 5% by wt. of polyurethane into the make-up of a polyacrylonitrile fiber made it possible to increase the resistance of the fiber to abrasion, double bending, and repeated extension.Translated from Khimicheskie Volokna, No. 1, pp. 42–43, January–February, 1985.     

Dynamic mechanical properties of carbon fibers

We have determined the dynamic mechanical properties in a low frequency range (0.01–10 Hz) of carbon and graphite fibers at different temperatures and evaluated the influence of fiber stretching. The results, showing frequency and extension dependent losses and changes in Young's moduli, indicate the presence of relatively large, independently mobile fiber constituents, which appear to correspond to the slowly undulating ribbons recognized earlier as the basic carbon fiber components.     

Extraction of zinc from low-concentration solutions in the manufacture of viscose fibers

Conclusions The process of zinc regeneration by the method of extraction from solutions close in composition to the wash water from viscose fiber manufacture has been studied under laboratory conditions.It is recommended to carry out the extraction of zinc with a 30% solution of D2EHPA in kerosene at a pH of 2–3 and an O:W ratio of 1:1.It is recommended to use a 15% sulfuric acid solution or a solution of precipitation bath as the re-extractant.Translated from Khimicheskie Volokna, No. 4, pp. 31–32, July–August, 1983.     

Experiments with hot drilling for mining quartzite

Conclusions Quartzites from the pit of the Pervourals Dinas factory can be effectively broken up with the thermal method.The effective rate of input of the thermal bit is 7–9 m/h in the broken-up part of the massive. The upper 3–4 m can be drilled with a rate of 5 m/h. The most effective rate of drilling for the thermal bit is 10–12 rpm.Drilling with a hot-drilling machine in small deposits of quartzites is possible only in conditions of complete dust suppression.Questions connected with the extension of the drilling frame and the formation of depressions are of practical interest and work in this area will be continued.     

Thermal drawing of polyacrylonitrile fiber after plasticization drawing with a different ratio

The maximum possible drawing ratio is essentially a function of the plasticization drawing ratio of the sample. Samples with a different plasticization drawing ratio have the same type of change in the mechanical properties during thermal drawing. Selection of the optimum conditions of thermal drawing of a fiber is a function of the plasticization drawing ratio. It is preferable for samples with a high plasticization drawing ratio to undergo thermal drawing to obtain high strengths.All-Russian Scientific-Research Institute of Synthetic Fibers, Tver'. Translated from Khimicheskie Volokna, No. 4, pp. 41–42, July–August, 1992.     

A comparison of the physico-mechanical properties of unidirectional organic-plastics based on epoxy and on polyamide binders

Conclusions -- A comparison of the physicomechanical properties of organoplastics using epoxy or polycaproamide matrixes has shown that the epoxy binder ensures a better realization of the properties of high-strength organic yarns and plastics under extension. The highest figures are obtained for Armos or SVM yarns.-- Under conditions of bending loads, the properties of organoplastics with different reinforcing yarns (Armos, SVM, and Terlon) are close to each other, and for organoplastics with a polycaproamide matrix it is possible to attain higher strength figures than for epoxy plastics.Translated from Khimicheskie Volokna, No. 5, pp. 46–48, September–October, 1991.     

A two-stage preparation of mesophase pitch from the vacuum residue of FCC decant oil

The preparation of mesophase pitch as a precursor for the high-performance carbon fiber from a vacuum residue of FCC-decant oil (FCC-DOVR) was studied, applying a two-stage heat treatment to improve the pitch yield as well as its liquid crystal properties. The present two-stage preparation consisted of the pressurized heat treatment (1–5 MP) of the first stage at 430–480°C and the successive heat treatment under 13–260 Pa at 430°C. Such a two-stage preparation increased the yield of the spinnable mesophase pitch of 100% domain texture with lower softening point to 45% from 22% by the single-stage one from the same feedstock. Spinning properties of the mesophase pitch were excellent to allow smooth spinning for longer than 15 min and random orientation of mesogen molecules in the tranverse section of the fiber perpendicular to the fiber axis. The chemistry of the two-stage preparation for the higher yield and better properties as the fiber precursor is briefly discussed.     

Hydraulic resistance of a deformable layer of fibrous material

Filtration of spinning solutions, spinning bath, and finishing solutions through a layer of fibrous material is widely used in different chemical fiber plants. In finishing of textile fibers on spools and cakes, the liquid is filtered through a layer of fiber attached by winding. At the same time, filtration is through a layer of unattached, freely packed fibrous material with random orientation of the individual fibers or through layers of nonwoven material in filtration on filters with a metal — gauze — asbestos gravity layer, in fiber finishing or modification processes, and in processes involving ion-exchange, chemisorption, and catalytically active fibrous materials.Moscow State Textile Academy. Translated from Khimicheskie Volokna, Vol. 25, No. 1, pp. 13–15, January–February, 1993.     

Some special features in the preparation of amino phosphorus-containing polyacrylonitrile ion-exchange fibers and some of their physicochemical properties

Conclusions It is possible to prepare a nitrogen- and phosphorus-containing polyampholyte by treating an amino-containing polyacrylonitrile fiber with phosphorous acid and formaldehyde by the Kabachnik-Fields reaction.The ion-exchange properties of the fiber are determined by the concentrations of the modifying reagents, and by the time and temperature of treatment.Translated from Khimicheskie Volokna, No. 4, pp. 40–41, July–August, 1983.     

Shock Compression and Spalling of Cobalt at Normal and Elevated Temperatures

Searching for a possibility of registering polymorphic transformations in cobalt under rapid extension, we measured free-surface velocity profiles of high-purity cobalt samples subjected to shock-wave loading at temperatures of 20–400 °C. In this temperature range, the spalling strength of cobalt at rates of its extension of 10⁵ – 10⁶ sec^–1 was measured, and the relaxation properties of this material under compression in the shock-wave front were estimated. In the experiments, we failed to observe expected wave-profile anomalies due to possible high-temperature polymorphic transformation of cobalt under extension. Most probably, the volume change due to transformation is too small to exert notable influence on the wave-profile structure. Key words: high-purity cobalt, shock compression, phase transformations, spalling strength, temperature.     

Problems in preparing organoplastics based on highly oriented polyethylene fibres

Conclusions -- Some special features of epoxy organoplastics based on highly oriented polyethylene fibres have been determined, which consist in a low strength in shear, compression, or transverse extension, which are 4–6 times less than those of composites based on aramide fibres and which are caused by low adhesive interaction.-- Some basic ways of preparing monolithic polyethylene plastics have been shown, the most important of which are based on increasing the adhesive strength of fibres to the binder or by autohesive binding of the fibres.-- The possibility of preparing organoplastics of various types based on polyethylene fibres with a strength level in extension not less than 1.5 GPa, and elastic modulus up to 90–120 GPa, at a density not over 1100 kg/m³ has been confirmed.Translated from Khimicheskie Volokna, No. 4, pp. 36–39, July–August, 1990.     

Solid electrolyte galvanic cell under load

Relationships are derived which describe the voltage of and the ionic and electronic currents through a solid electrolyte galvanic cell under load as an explicit function of the independent variables. These relationships result from an appropriate extension of the classical Wagner approach for the open circuit case to the conditions of a cell in charge or discharge mode. The formulae represent generalized versions of the Wagner–Schmalzried equations. They readily allow determination of the chemical potential distribution throughout the electrolyte under load conditions.     

The heat resistance of silicon dioxide-base fiber thermal insulation

Conclusions The high heat resistance of amorphous fiber high-silica materials is shown. The presence of the crystalline phase (cristobalite) decreases their heat resistance.The critical temperature range (200–250°C) in which intense crack formation and failure of fiber high-silica thermal insulation materials containing cristobalite occurs is established.Translated from Ogneupory, No. 4, 53–55, April, 1987.     

Modification of polyamide fibers by forming an interpenetrating polymeric system in the surface layer

Conclusions The proposed method of modifying a polyamide yarn is based on the formation of an interpenetrating polymeric network in its surface layer.The optimum IPN content of a yarn for the system examined is 2–6 or 21–23% by wt.The presence of an IPN in the surface layer of a fiber ensures an increase in strength and heat-resistance, and in the adhesive strength of the bond with a polymeric matrix.Translated from Khimicheskie Volokna, No. 4, pp. 14–16, July–August, 1983.     

Effect of the duration of storage on the mechanical properties of high-strength polyethylene fibers

It was shown that the mechanical properties do not change during prolonged storage of high-strength polyethylene fiber containing residual solvent.Translated from Khimicheskie Volokna, No. 1, pp. 41–42, January–February, 1995.     

Introduction of industrial production of polycrystalline oxide fibers

Conclusions Using the technology developed in the Ukrainian Scientific-Research Institute for Refractories, Pervoural'sk Dinas Plant has mastered production of polycrystalline aluminum oxide fibers with service temperatures up to 1400–1500°C and high thermal insulation properties. For the purpose of broadening the possibilities of use of this new fiber material Pervoural'sk Dinas Plant is introducing production of high-temperature rigid plates based on this fiber with a service temperature up to 1600°C.In 1988 the saving from the production of aluminum oxide fiber in the plant was 80,000 rubles.Translated from Ogneupory, No. 4, pp. 34–36, April, 1990.     

Fibers from a mixture of cellulose triacetate and polystyrene

Conclusions The introduction of a nonfiber-forming substance — polystyrene — into cellulose triacetate does not cause the formation of long microfibers in the polymer matrix; the polystyrene is distributed along the fiber axis in the form of stretched-out regions.The addition of polystyrene helps increase the strength figures for triacetate fibers by more than 20%.Translated from Khimicheskie Volokna, No. 4, pp. 37–38, July–August, 1983.     

Preparation of fibers from mixtures of polymers based on polyvinyl chloride

Conclusions Structural modification of polyvinyl chloride by introducing a heat-resistant polyamide into it makes it possible to prepare fibers with increased thermal resistance.Fabric prepared from the modified fiber has adequate strength and has less shrinkage.Translated from Khimicheskie Volokna, No. 4, pp. 35–37, July–August, 1983.     

Separation of stearox-6 from aqueous media by the use of hollow-fiber ultrafilters

Conclusions -- The fundamental possibility of effective separation of Stearox-6 from waste water in the manufacture of viscose fiber by the use of hollow-fiber ultrafilters has been demonstrated.Translated from Khimicheskie Volokna, No. 2, pp. 41–43, March–April, 1993.     

Glass Formation and Physicochemical Properties of Alloys in the Cu–Te–I System

The glass formation and the physicochemical properties of alloys in the Cu–Te–I system are investigated. Consideration is given to the glass formation region in the Cu–Te–I system, the results of differential thermal and X-ray powder diffraction analyses, and the temperature dependence of the molar volume for melts. The phase diagram is constructed along the CuI–Te join passing throughout the glass formation region. The inference is drawn that the formation of the CuTeI and CuTe₂I chemical compounds favors extension of the glass formation region in the system under investigation.