Mechanism of the propagation and damping of ultrasound in bulk-looped acetate-polyamide yarns

Conclusions Analysis of the reasons for dissipation of ultrasonic wave energy in bulk-looped acetatepolyamide yarns has made it possible to establish the following:ultrasonic waves are propagated only along the cone (principal) polyamide yarn; there-upon an anomalously large damping of ultrasound is observed as compared with damping in smooth yarns;scattering of ultrasonic energy is determined by the character of the interaction between the principal fibre and the fill-in fibre.Translated from Khimicheskie Volokna, No. 6, pp. 40–42, November–December, 1986.     

Interconnection between preparation parameters and the strength of texturized combined yarns

Conclusions The laws governing changes in breaking diagrams of texturized combined yarns as functions of technological parameters in their preparation have been studied.It has been found that, with increase in the amount of viscose fibre sheathing, a decrease in elastic modulus of the combined looped yarns takes place, plus an increase in the coefficient of utilization of the strength of the core yarn.Translated from Khimicheskie Volokna, No. 3, pp. 32–34, May–June, 1987.     

Change in deformation properties of complex polyamide yarns under conditions of variable atmospheric humidity

Conclusions The change in deformational properties of polyamide yarns during the aging process is explained by a densening of their structure during water vapor sorption-desorption cycles at a variable humidity of the surrounding medium.Under conditions of variable humidity, the elastic component of deformation rises, approaching the analogous figure for heat-treated fibre.Translated from Khimicheskie Volokna, No. 2, pp. 48–49, March–April, 1985.     

海藻纤维及其混纺纱线的性能研究

为了迎合市场对保健功能针织产品的需求,对海藻纤维及海藻纤维-棉(50/50)混纺纱的基本性能进行了测试。分别采用傅里叶红外光谱仪和扫描电镜对海藻纤维进行测试和观测,发现海藻纤维横截面呈不规则的锯齿状,纵向纹路整齐、粗细均匀。分析了海藻纤维-棉混纺纱线的物理、化学性能得出:海藻纤维-棉混纺纱断裂伸长率较大,单纱强力一般;条干均匀度较好;毛羽一般;捻度不匀率较低;耐碱性较好但不耐强碱,不耐酸。     

Preparation of crimped synthetic yarns directly during the spinning process

Conclusions The practical possibility of preparing yarns with an adequate crimp directly during the spinning process without expensive operations to give yarns a crimp by mechanical means has been demonstrated experimentally.Yarn crimp is achieved by using spinnerets having holes of variable cross-section; this ensures obtaining yarns with a head-tail cross-sectional profile.The authors express their thanks to K. H. Gaitel, a specialist in the Schwartz (East Germany) man-made fibre company and to F. Dolke and G. Tuschan, specialists in the spinneret manufacturing plant in Grebzig (East Germany) for help in carrying out this work.Translated from Khimicheskie Volokna, No. 2, pp. 40–42, March–April, 1985.     

Effect of pneumotexturizing on surface topography of polyethylene terephthalate and viscose yarns

Conclusions A classification of the basic types of defects in the surface of viscose yarns and yarns from polyethylene terephthalate which arise as a result of actions which take place during the pneumotexturizing process has been made.A qualitative estimate of the density of defects agrees with data on the strength characteristics of yarns which have been subjected to texturizing at various fibre movement speeds and air pressures in the nozzle of the aerodynamic device.Translated from Khimicheskie Volokna, No. 4, pp. 28–29, July–August, 1988.     

Molecular-weight distribution of cellulose triacetate and the strength of fibres and films

Conclusions The effect of the molecular-weight composition of CTA on the physicomechanical properties of films and yarns has been examined.The possibility of processing a mixture containing an addition of high-molecular CTA into fibre has been demonstrated.An increase in the strength of yarns and films containing an additive of high-molecular CTA has been established.Saratov State University. Translated from Khimicheskie Volokna, No. 2, pp. 42–44, March–April, 1992.     

Effect of metal salts on the wettability of synthetic fibres

Conclusions The effect of treating fibres of yarns with solutions of metal chlorides in various solvents on their wettability has been investigated. To determine the applicability of the proposed methods for evaluating fibre and yarn wettability and hygroscopicity, a comparison of experimental data with literature information on equilibrium moisture contents has been made.It has been found experimentally that three basic factors exert an effect on fibre wettability: the character of the metal cation used, the type of solvent, and the concentration of the metal salt.The effect of additions of metal chlorides on Kapron yarn was evaluated by a modified Washburn procedure, consisting of measuring the rate of ascent of an aqueous dye solution along a vertically disposed yarn.Treatment of Kapron with lithium chloride solutions leads to an improvement in its wettability, which is the premise for a chemical modification of Kapron fibre with the objective of improving its hygroscopicity.Translated from Khimicheskie Volokna, No. 2, pp. 35–37, March–April, 1988.     

Effect of hyperbranched poly(citric polyethylene glycol) with different polyethylene glycol chain length on starch sizing and compatibility with blended yarns

Blend of starch and water-soluble polyester has been widely used in warp sizing because of its good film-forming, biodegradability, and adhesion to polyester/cotton blended yarns (T/C). In this study, a series of hyperbranched polyesters poly(citric polyethylene glycol) (PCPEG) with varied chain length of polyethylene glycol (PEG) were prepared with citric acid and PEG at molar ratio of 1:3 and 150 °C for 3 h in vacuum and characterized by Fourier transformed infrared, gel permeation chromatography, and ¹H nuclear magnetic resonance. PCPEG blended maize starch (PCPEG/MS) as sizing agent of T/C 80/20 and effects of PEG chain length of PCPEG on the property of the blending sizing agent were studied. Results indicated PCPEG could improve the compatibility between starch and T/C 80/20 and the optimum content of PCPEG as blended sizing agent was 8%. PCPEG not only decreased apparent viscosity of MS paste but also increased viscosity stability of the paste. In addition, with increase of PEG chain length of PCPEG, viscosity stability of PCPEG/MS paste increased, but the value of all adhesion performances of T/C 80/20 after sizing decreased. Long chain of PEG is not good for compatibility between PCPEG and starch. The starch blending PCPEG has potential applications in sizing blended yarns in textile industry. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48928.     

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.     

Structure and properties of dyed polypropylene yarn containing an addition of chemically colored low-molecular polycaproamide

Conclusions The thermal properties of PP yarns have been studied by determining their weight loss on heating. It has been shown that, by comparison with unmodified PP yarn, yarns containing an addition of chemically dyed LMPCA have improved thermal stability.Addition of chemically dyed LMPCA in the spinning of PP yarn leads to an increase in mean crystallinity and a decrease in the average size of yarn crystallites after jet stretch. The existence of two morphological forms of supermolecular structure has been shown by the electron microscopy method: spherulitic and oriented along the yarn axis.Translated from Khimicheskie Volokna, No. 6, pp. 20–21, November–December, 1986.     

Constructional features of machines for making man-made fibres from solutions

Conclusions A series of machines has been developed for the manufacture of viscose textile yarn, viscose technical yarn, polyacrylonitrile fibre, and so on.The new units of these machines for spinning yarns from solutions are spinning units with a U-shaped tube, cascade washing, a spindle with tension regulation by use of annular permanent magnets, mirror adjustment of yarns in adjacent sections, and a take-up and winding mechanism with a mobile bobbin.Thanks to the application of these units, an increase in machine productivity has been assured, plus an improvement in the physico-mechanical indices of the product produced.Translated from Khimicheskie Volokna, No. 3, pp. 8–11, May–June, 1989.     

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.     

Technological features of the manufacture and textile processing of acetate yarns having enhanced compactness

Conclusions The technological features of the manufacture of pneumatically connected twisted (80 twists/m) yarns and possibilities of their textile processing have been examined.It has been shown that yarns with the structure obtained can be used in weaving instead of twisted yarns with a twist of 136 twists/m.Translated from Khimicheskie Volokna, No. 4, pp. 35–37, July–August, 1986.     

Colour gamut of natural dyes on cotton yarns

Cotton fibres were dyed using various natural dyes alone and in combination to yield six basic shades: blue, yellow, red, black, green and fawn. These dyed fibres were then blended in various proportions along with undyed cotton fibres and spun on a rotor-spinning machine to produce 204 coloured yarns. The fastness properties of the six basic shades were determined. The L * a * b * and L * C * h values of the yarns having 50% dyed fibre and 50% undyed cotton fibre was also determined. The values were plotted to obtain the colour gamut of natural dyes on cotton yarns.     

Thermal stability of polyquinolineterphenyl fibres

Conclusions The build-up of internal stresses in polyquinolineterphenyl fibres during spinning and heat-stretching causes a decrease in their thermal stability. The formic acid used as a solvent in fibre prepration brings about a similar action.The thermal stability of the fibre can be increased if it is subjected to the action of temperature under a current of inert gas.Translated from Khimicheskie Volokna, No. 4, pp. 20–22, July–August, 1988.     

Rate of propagation and of damping of ultrasound in polycaproamide fibres of elastics

Conclusions The change in propagation rate and in damping of ultrasound in elastic polycaproamide yarns has been studied. It has been found that the change in these figures is determined by the same mechanism as in yarns from the press chamber method of preparation.A region of high values of the damping coefficient (25–33) has been found for elastic yarns.Texturizing yarns by the false twist method exerts a more intense action on the polymer than the compression and bending deformation in chamber pressing.The dependence between the rate of propagation of ultrasonic waves and the damping coefficient for elastic yarns reflects the effect of molecular orientation in the polymer itself and the geometric orientation of sections of the crimp relative to the sonication direction.Translated from Khimicheskie Volokna, No. 3, pp. 46–48, May–June, 1984.     

Properties of yarns spun from a cellulose triacetate melt

Conclusions The physicochemical and physicomechanical properties of yarns spun from a cellulose triacetate melt have been studied.It has been shown that in physicomechanical properties CTA yarns spun from the melt are identical to yarns spun by the dry method.It has been found that the lower sorptive power and lower shrinkage of yarns from the melt are connected with the special features of their spinning.Translated from Khimicheskie Volokna, No. 5, pp. 23–25, September–October, 1984.     

Shrinkage of texturized Kapron fibres in crimp

Conclusions In a study of Kapron yarns texturized by the press-chamber method, a dependence has been observed between the maximum shrinkage in the crimp on heating and the resistance of the crimp to the action of straightening-out loads.The existence of an inverse relationship between these phenomena is caused by the special features of the change in degree of molecular orientation of the polymer in the crimp during the texturizing process.By shrinkage in crimp is understood the change in the angle at the vertex and the fibre length in the crimp on heating.Translated from Khimicheskie Volokna, No. 5, pp. 34–35, September–October, 1983.     

Chemical cross-linking of carboxymethylated viscose yarns

Conclusions The parameters of chemical cross-linking of yarns based on carboxymethylcellulose (CMC) and their physicomechanical properties depend on the concentration of the cross-linking agent — formaldehyde — the catalyst concentration, and also on the reaction temperature and time.A bound formaledhyde content of 0.5% by wt., in the form of methylene bridges in the make-up of CMC yarns, leads to a 31% increase in their strength in the wet state.Chemical cross-linking of CMC fibres with formaldehyde helps increase their resistance to biodegradation and correspondingly leads to a larger strength retention in living organisms.Translated from Khimicheskie Volokna, No. 5, pp. 18–20, September–October, 1989.