Increasing the stability of pump operation in metering solutions of polyoxadiazole in sulfuric acid

Conclusions The basic reasons for failure in the operation of spinning gear pumps in metering solutions of polyoxadiazole in concentrated sulfuric acid have been studied.The possibility of eliminating blockage of gear pumps, reducing nonuniformity in delivery of spinning solution, and considerably increasing the stability of spinning Oksalon fibre has been demonstrated.Translated from Khimicheskie Volokna, No. 2, pp. 54–55, March–April, 1986.     

Effect of sulfuric acid treatment on the physicomechanical properties of polyphenyleneoxadiazole fibres

Conclusions By treatment of undried polyphenyleneoxadiazole yarns with concentrated sulfuric acid under isometric conditions, it is possible to raise their strength by 20–30% and their elongation at break 40–50%.The improvement in physicomechanical properties of the yarns which have been treated with acid is caused by a reduction in internal stresses, an improvement in the interlayer packing of the macromolecules fragments, and an increase in the degree of orientation of the macromolecules.Translated from Khimicheskie Volokna, No. 6, pp. 33–35, November–December, 1985.     

Role of slippage in the orientation stretch of Oksalon yarns

Conclusions It has been shown that in the continuous orientation stretching of Oksalon yarn in air, the deformation region is located close to the first stretch roll, including an arc of yarn slippage on it.The need to take the slippage arc into account in continuous yarn stretching has been demonstrated.By varying the frictional parameters of the first stretch roll, it is possible to achieve an increase in the strength of the finished yarn.Translated from Khimicheskie Volokna, No. 5, pp. 22–23, September–October, 1985.     

Effect of physically active media on yarn orientation strengthening

Conclusions The effect of deforming Oksalon yarn in Various physically active liquid media on its physicomechanical properties has been studied.The action of water or carbon tetrachloride, with simultaneous deformation of the complex yarn, aids in reducing the cementation of elementary filaments, and assists polymer orientation molecular order, and raises the physicomechanical properties of the yarn.In the stage of high-temperature stretching, an increase in the efficiency of orientation strengthening is observed as a result of preliminary deformation of the yarn in physically active media.Translated from Khimicheskie Volokna, No. 3, pp. 27–29, May–June, 1985.     

Surface antistatic treatment of polyamide yarns with long-chain quaternary ammonium salts of hydroxymethanesulfonic acid

Conclusions A surface treatment of polyamide yarns in the stages of spinning and stretching has been described, with aqueous solutions of long-chain quaternary ammonium salts of hydroxymethanesulfonic acid, with subsequent heat-setting, as a result of which the yarns acquire long-term antistatic properties.The optimum conditions for surface antistatic treatment of polyamide yarns which have been selected permit one to carry out this process on equipment which is used in the preparation of serially produced complex yarns and fibres.Translated from Khimicheskie Volokna, No. 4, pp. 36–38, July–August, 1987.     

Deformation of technical purpose woven tapes

Conclusions An analogy has been found between the viscoelastic properties of yarns and fabrics which makes it possible to apply a previously developed rapid method of determining deformation characteristics to fabrics.The possibility of applying the nonlinear hereditary viscoelasticity equation for calculating the stretching diagrams of woven tapes, with allowance for the specifics of their deformation, has been established.Translated from Khimicheskie Volokna, No. 3, pp. 45–47, May–June, 1993.     

Factors which determine the drawability of yarns from melts of polycaproamide-polyolefin mixtures

Conclusions An increase in spinneret hole diameter leads to an increase in the maximally attainable orientation stretch ratio for composite fibres from polycaproamide-low-pressure polyethylene and polycaproamide-polypropylene mixtures.On transition to spinnerets with holes of large diameter, a decrease in the contribution of pre-jet stretch to overall deformation of disperse phase particles is the main factor which brings about an increase in the ability of the indicated composite yarns to undergo thermal orientation stretching.Translated from Khimicheskie Volokna, No. 6, pp. 28–29, November–December, 1988.     

Regeneration of KU-2-8 resin with precipitation baths from viscose manufacturing

Conclusions The process of regenerating KU-2-8 resin with precipitation baths from viscose manufacturing has been investigated as compared with regeneration with sulfuric acid.It has been found that desorption of zinc from the resin by precipitation baths is rather efficient, which makes it possible to use precipitation bath in the regeneration process instead of 10% sulfuric acid solution.It has been shown that a high content of organic contaminants in the precipitation baths (COD of 2000–5661 mg O₂/liter) does not affect the sorptive properties of KU-2-8 resin.Translated from Khimicheskie Volokna, No. 6, pp. 9–10, November–December, 1984.     

Mechanism of fibril extension in a deformable composite yarn of the “matrix-fibril” type

Conclusions For composite yarns of the matrix-fibril structure, the fibril distribution which is attained in the stretching process with respect to stretch ratio (and correspondingly with respect to mean degree of molecular orientation) is brought about the original fibril distribution by size (diameter and length).In the orientation stretching of a composite yarn, the stretching of fibrils takes place with a stretch ratio equal to or less than the stretch ratio of the matrix.Translated from Khimicheskie Volokna, No. 2, pp. 3–5, March–April, 1989.     

Preparation of polycaproamide yarns with reduced static

Conclusions Yarns with a high antistatic effect, which is stable to wet treatments, have been obtained by introducing product DETA80 into polycaproamide.DETA80 antistat causes changes in the supermolecular structure of yarns which lead to a reduction in strength and deformation properties of the yarns and to an increase in their ability to be dyed.The antistats do not exert an effect on the light-resistance of the yarns, nor on resistance of the color to set treatment.Translated from Khimicheskie Volokna, No. 5, pp. 54–55, September–October, 1984.     

Effect of spinning conditions on the stationary regime region in stretching a jet of a solution of poly-p-phenyleneterephthalamide in an air gap

Conclusions -- The spinning of a yarn from sulfuric acid solutions of poly-p-phenyleneterephthalamide through an air gap in the region of high stretch ratios is unstable because of the onset of pulsations in jet diameter, which is known for polymer melts as stretching resonance.-- The onset of resonance depends on the diameter of the holes in standard cup-shaped spinnerets in the range 0.06–0.1 mm.-- The region of stationary jet-stretching regimes without resonance is considerably expanded in the case of forced cooling of the jet of PPTA solution in the air gap.Deceased.Translated from Khimicheskie Volokna, No. 2, pp. 17–19, March–April, 1993.     

Regeneration of coagulant from aluminum hydroxide containing precipitates from water-softening stations of viscose fibre plants

Conclusions Optimum parameters for the regeneration of aluminum from the sludge of the Kalininskii Khimvolokno PO water softening station with a 1.5% sulfuric acid solution have been determined. The regeneration efficiency is 85–95%.The fundamental possibility of cleaning up natural waters with regenerated coagulant has been shown by experiments on an experimental set-up.It is recommended to use gas purification wastewater, containing 10–20 g/liter of sulfuric acid, in viscose fibre plants as the reagent for acid treatment of the sludge from water-softening stations.Translated from Khimicheskie Volokna, No. 4, pp. 57–59, July–August, 1986.     

Fatigue life of man-made yarns under repeated stretching with allowance for recovery

Conclusions -- The presence of rest in stages of preliminary fatiguing up to 40% of the fatigue resistance of yarns in repeated stretching without rest leads to an increase in total fatigue resistance of complex man-made yarns, while rest in fatiguing stages above 70% affects this figure to a smaller extent. With increase in duration of the rest, this tendency is retained and the absolute values of total fatigue resistance of the yarns rise.-- Breakdown processes in fatigue yarns become marked when further rearrangement of the supermolecular becomes impossible, for example, on attaining a definite molecular orientation in them. Starting at this stage in fatiguing, rest shows up steadily in smaller degree in the total fatigue resistance of yarns.Translated from Khimicheskie Volokna, No. 1, pp. 42–44, January–February, 1991.     

Effect of spinning conditions on the properties of profiled yarns prepared by the aerodynamic method

Conclusions The effect of spinning conditions on the physicomechanical properties of freshly-spun profiled yarns prepared from polymer melts by the aerodynamic method has been investigated.Physicomechanical properties of profiled and round yarns have been compared.It has been found that the strength of profiled yarns of three-sided, four-sided, or six-sided cross-section is attained at the least stresses. This guarantess more stable spinning and stretching conditions as compared with yarns having other forms of profile.Translated from Khimicheskie Volokna, No. 6, pp. 36–38, November–December, 1985.     

Determination of the viscoelastic properties of synthetic yarns on the basis of short-term testing

Conclusions A method has been developed for determining the deformation characteristics of polycaproamide yarns, which differs from the previously known ones by allowing for relaxation contributions in loading the specimen.The parameters obtained by the indicated method permit one to calculate a family of relaxation curves at a deformation up to 25–30% of the breaking value, relaxation times up to 10³ sec, and with an error which does not exceed experimental error.Stretching diagrams and stress relaxation curves at long relaxation times can be calculated with an accuracy sufficient for engineering calculations.Translated from Khimicheskie Volokna, No. 2, pp. 24–25, March–April, 1988.     

Physicochemical bases of spinning viscose fibre of yarns into an aluminum sulfate precipitation bath

Conclusions The use of zinc-less aluminum sulfate precipitation baths in the manufacture of viscose fibre or yarn affords the following opportunities:Preparation of fibres with less strength loss in the moist state; low shrinkage fibres with a stable crimp which does not disappear on moist treatment; fibre with a high modulus and high strength in the moist state, that is, high-modulus viscose fibres and yarns;making wastewater harmless by replacing zinc salts by harmless aluminum salts and by increasing the degree of clarification and purification of the wastewater because of the content of aluminum sulfate in it, which acts as a coagulant;attainment of an ecological and economic benefit as a result of eliminating the expensive zinc sulfate from the technological process and reducing the specific norms for consumption of sulfuric acid, thanks to the use of low-concentration (in acid) precipitation baths.Translated from Khimicheskie Volokna, No. 2, pp. 34–36, March–April, 1986.     

Spinning viscose technical yarn into a bicomponent precipitation bath

Conclusions -- The possibility has been demonstrated of preparing viscose yarn by the centrifugal method from a viscose containing additions of urea by spinning into a bicomponent precipitation bath containing sulfuric acid and sodium sulfate.-- Optimum conditions for spinning viscose yarn have been established: a sulfuric acid content of 115 g/l in the precipitation bath, a urea content of 2.5% based on weight of -cellulose in the viscose, and an orientation stretch of 22%.-- Specimens of viscose yarn having a linear density of 13.3 tex have been prepared with a relative breaking load of up to 19 cN/tex, an elongation at break of 17–19%, and a mean squared deviation in dyeing nonuniformity of 0.8–1.0.Translated from Khimicheskie Volokna, No. 4, pp. 33–34, July–August, 1990.     

A combined process for double-twisting and heat-treating textile grade polyester yarn

Conclusions The use of a technological scheme which combines the processes of twisting and yarn heat-treatment makes it possible to intensify the process of textile grade polyester yarn manufacture as a result of shortening the series of textile-technology steps.The scheme permits one not only to set the twist well, but also to regulate the basic physicomechanical properties of the yarns over a wide range.By using the proposed technological scheme, depending on the assigned degree of deformation, one can obtained twisted yarns with a shrinkage of 1–2% at an initial elastic modulus up to 20 MPa.Translated from Khimicheskie Volokna, No. 6, pp. 32–33, November–December, 1984.     

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.     

Heating of synthetic yarns during the process of stretching and heat-setting

Conclusions It has been proposed to determine the mean yarn temperature in the cold stretching zone, and also the power which it is necessary to supply to the yarn from the stretching mechanism side, from stretching process technological data.The coefficients of friction of polyamide and polyester complex yarns on pyroceram rolls and stretch cylinders have been determined experimentally.Translated from Khimicheskie Volokna, No. 3, pp. 44–46, May–June, 1987.