Graft polymerization of acrylonitrile on acetate yarn under the action of gamma radiation

Conclusions The graft polymerization of acrylonitrile from the vapor phase on acetate yarn under the action of -radiation has been studied. Conditions have been discovered for the preparation of modified acetate yarns with a degree of acrylonitrile grafting from 1.5 to 68.0 by wt.The possibility of increasing the resistance of acetate yarns to abrasion no less than 15-fold, with a simultaneous increase in breaking strength and retention of resistance to double bends, has been demonstrated.Translated from Khimicheskie Volokna, No. 1, pp. 25–27, January–February, 1988.     

A device for the take-up of pneumatically tangled acetate yarns onto a spinning package

Conclusions Three variants of take-up and winding devices have been developed; these permit one to take up yarn from the spinning machine onto a commercial package by a frictionless method and ensure a constant linear velocity of yarn winding.The device operates under the following regimes: linear winding rate, 400–600 m/min; yarn tension up to regulating roll, 4.5–5.0; tension after it, 8–9 cN; weight of package, 3 kg.The devices ensure obtaining acetate pneumatically tangled yarns with 15–35 pneumatically tangled sections per m of yarn with a uniform distribution over the yarn length; the density of the yarn in the package is 850–950 kg/m³.Translated from Khimicheskie Volokna, No. 1, pp. 46–48, January–February, 1985.     

Normalization of specific electrical resistance characteristic of complex acetate yarns

Conclusions It has been shown that, regardless of the type of lubricant or its content on acetate textile yarn, an essentially identical decrease in specific electrical resistance is observed.The specific electrical resistance of acetate yarns which have been treated with lubricants lies in a range which ensures normal processing of such yarns into textile articles.Translated from Khimicheskie Volokna, No. 6, pp. 20–21, November–December, 1989.     

Mechanism and kinetics of shrinking of texturized composite fibres having a matrix-fibrillar structure

Conclusions The mechanism and kinetics of shrinkage of complex texturized composite yarns having a matrix-fibrillar structure, and also of yarn shrinkage in a crimp, have been studied.It has been shown that the behavior of a yarn in a crimp on heating, and also the shrinkage of complex texturized yarns, depends considerably on the disposition of the polyethylene fibrils in the polycaproamide matrix.Spinning yarns with a nonuniform disposition of fibrils in the matrix permits one to obtain texturized yarns with a combined spatial-planar twist and an elevated bulkiness.Translated from Khimicheskie Volokna, No. 3, pp. 32–34, May–June, 1988.     

Determination of the shear modulus of yarns in twisting

Conclusions Experimental data on the effect of linear density and yarn structure on shear modulus in twisting polycaproamide yarns support an inverse dependence of the shear modulus in twisting on linear density and on number of elementary filaments in the complex yarn.It has been demonstrated theoretically and experimentally that the calculational formula in the VNIIV procedure is suitable only for determining the shear modulus in twisting monofilam and is not suitable for calculating the shear modulus of complex yarns.An equation has been derived which is recommended for determining the shear modulus of yarns of various structures using a twisting pendulum.Translated from Khimicheskie Volokna, No. 1, pp. 37–38, January–February, 1986.     

A study of the high-speed spinning process for polycaproamide complex yarns

Conclusions -- The basic laws governing the effect of spinning conditions on the properties of PCA yarns have been investigated. It has been shown that in distinction to spinning monofilaments, in high-speed spinning of complex yarns, additional factors appear by use of which it is possible to effectively control the properties of the yarns obtained.-- It has been found that the site of disposition of the aqueous lubricant in the high-speed spinning PCA yarns exerts a fundamentally different action on the breaking elongation of the yarns and on their structure, depending on the linear density and the number of elementary filaments in the complex yarn; however, it does not change the character of this dependence on the breaking strength of the yarn.-- Under otherwise equal conditions, a lower disposition of the lower lubricating device helps in obtaining complex PCA yarns which have a larger breaking strength and a lower elongation.Translated from Khimicheskie Volokna, No. 1, pp. 19–21, January–February, 1991.     

Technological principles in texturizing polycaproamide yarns

Conclusions Texturization of yarns by the press-chamber method leads to the formation of twists of the flat zig-zag type on smooth yarns. Because of the receipt of crimp, a yarn is obtained with an increased bulk and improved heat-insulating, and hygienic properties.After texturizing, appreciable changes take place in the structure and morphology of elementary filaments. The latter causes a change in the complex of physicomechanical yarn properties.By the use of basic technological texturizing parameters, it is possible to vary the characteristics of the basic specific properties of crimped yarns.Translated from Khimicheskie Volokna, No. 2, pp. 27–34, March–April, 1985.     

Some special features in texturizing complex Karbimid yarns

Conclusions The effect of the orientation stretch ratio of complex Karbimid yarns on their physicomechanical properties has been examined.It has been found that, to increase the ability of complex Karbimid yarns to undergo texturizing, it is advisable to use a yarn with a degree of orientation stretch of 600%.Translated from Khimicheskie Volokna, No. 1, pp. 32–33, January–February, 1984.     

Effect of spinneret hole diameter on the spinning and properties of acetate fibre

Conclusions The effect of the number and diameter of spinneret holes on hole clogging and the properties of acetate yarns has been investigated under manufacturing conditions.On reducing spinneret hole diameter and increasing the number of holes, the strength and fatigue properties are raised, but the elongation of acetate yarn is reduced.Translated from Khimicheskie Volokna, No. 1, pp. 29–30, January–February, 1986.     

Some features of mass-exchange processes in processing single complex viscose yarns

Conclusions Processes of mass-exchange in the inner and outer regions of single complex viscose yarns during their treatment have been examined.It has been shown that in complex yarns under tension, the rate of mass-exchange and of mass-transfer is reduced with increase in yarn tension and in the number of elementary filaments.Translated from Khimicheskie Volokna, No. 2, pp. 46–48, March–April, 1985.     

Connection between strength of organic complex yarns and reinforced plastics based on them

Conclusions The evaluation of the quality of elementary filaments of poly-p-amidobenzimidazole from the breaking load of a complex yarn 500 mm long should be taken as unfortunate.Testing specimens 30 mm long can be recommended for evaluating the quality of untwisted complex PABI yarns.Increasing the strength of complex yarns 30 mm long leads to a proportional rise in the strength of an organoplastic. In testing specimens of organoplastic 500 mm long, increasing the strength of the complex yarns by 10% leads to only a 3–4% rise in the strength of the organoplastic.The strength of a microplastic is a natural quality criterion for twisted complex yarns.Translated from Khimicheskie Volokna, No. 1, pp. 27–29. January–February, 1989.     

Change in properties of polycaproamide textile yarns on water-stabilization treatment

Conclusions The kinetics of washout of low-molecular-weight fractions from polycaproamide textile yarns during water-stabilization treatments has been studied. It has been found that the supermolecular structure of the yarns is considerably changed thereupon; the degree of crystallinity is increased, the size of the amorphous regions is reduced, the yarn porosity is increased, thereby increasing the rate of dye sorption, the yarn stress is reduced, and its shrinkage is lowered.The increase in yarn porosity as a result of water-extraction and stabilization treatment ensures raising their sorptive power with respect to dyes and various low-molecular-weight modifiers.Translated from Khimicheskie Volokna, No. 4, pp. 42–44, July–August, 1984.     

Evaluation of the character of strength distribution of elementary filaments by testing a complex yarn

Conclusions In the case of yarn based on an aromatic polyamide, it has been shown that the strength distribution of the elementary filaments in the complex yarn can be equally well described by the normal distribution laws or by a Weibull distribution.For the Weibull distribution, an analytical expression has been found which connects the strength variation coefficients of the complex yarn and of the elementary filaments.A method is suggested for evaluating the deviation in behavior of real complex yarns from that of bundle model, which consists in estimating the critical length of an elementary filament in the complex yarn. The method permits using the indicated model in practice.Translated from Khimicheskie Volokna, No. 4, pp. 38–39, July–August, 1985.     

Effect of twist angle and linear density of man-made complex yarns on contact wetting angle

Conclusions Contact wetting angles have been determined on complex twisting viscose, polyamide, and polypropylene yarns by the method of measuring a drop resting on the yarn.It has been found that the type of yarn, its linear density, and the twist angle affect the magnitude of the contact wetting angle.Translated from Khimicheskie Volokna, No. 3, pp. 41–42, May–June, 1988.     

Evaluating the defectiveness of yarns based on aromatic polyamides

Conclusions -- A procedure has been developed for evaluating the nonuniformity of elementary filaments in a cross section of a complex yarn.-- A procedure has been developed for estimating defectiveness and mean breaking tension of elementary filament from the results of testing the complex yarn.-- The procedures described can be used to evaluate the quality of yarns in optimizing the process of preparing them.Translated from Khimicheskie Volokna, No. 4, pp. 37–39, July–August, 1991.     

Effect of geometric characteristics of a specimen on the mechanical properties of polyaramide fibres

Conclusions -- The features of the deformation behavior of complex yarns from polyaramide fibres with different geometrical characteristics have been examined.-- It has been shown that the composition of the complex yarn essentially does not affect its deformation-strength or relaxation properties.-- The effect of specimen characteristics on the intensity of stress relaxation in a yarn has been determined.NII Plastmass, Moscow. Translated from Khimicheskie Volokna, No. 5, pp. 41–43, September–October, 1992.     

Effect of the moisture content of viscose textile yarns on their twist uniformity

Conclusions To obtain viscose textile yarns with a maximum twist uniformity, it is advisable to carry out the twisting operation at a yarn moisture content equal to or greater than 10–12% by wt.Raising the moisture content of a yarn to 17% only slightly affects twist uniformity.Reducing the linear density of the elementary filaments raises the twist uniformity of a viscose complex yarn.Translated from Khimicheskie Volokna, No. 2, pp. 40–41, March–April, 1984.     

Orientation processes in acetate yarns under the influence of certain solvent vapors

Conclusions Treatment of acetate yarns with vapors from solvents which form a liquid-crystal phase with the polymer leads to initiation of orientation processes which are accompanied by spontaneous yarn elongation. This makes it possible to prepare yarns of low linear density and with improved physicomechanical properties.It has been found that the action of vapor from nitromethane, which forms a lyotropic, liquid-crystal phase in cellulose acetates, takes place in several stages.A mechanism has been proposed for the interaction of the polymer with vapor from a solvent which forms a liquid-crystal phase with it.Translated from Khimicheskie Volokna, No. 2, pp. 13–15, March–April, 1989.     

Man-made fibres for carrets. Tendency in development

Conclusions The main direction of world development in the manufacture of man-made carpet yarns is modification of existing yarns with the purpose of improving the consumer properties of carpets — soil-repelling or soil-masking, antimicrobial, antistatic, or increasing yarn bulk, improving dyeability, resistance to ignition, etc.Reinforced carpet yarns and thread based on various combination of man-made fibres and complex yarns are finding steadily greater use in the manufacture of carpets.A new type of floor covering has appeared — carpet sheets, which are produced mainly by the tufting method at present.Translated from Kimicheskie Volokna, No. 5, pp. 18–23, September–October, 1987.     

Some special features in drying ordinary viscose textile yarns

Conclusions On machines for continuous spinning, finishing, drying, and twisting of viscose textile yarns without intermediate conditioning, the most favorable yarn moisture range is 10–13%; this ensures optimum physicomechanical indices and twist uniformity.In conductive-convective drying of viscose textile yarns which are in the drawn state, evaporation of moisture from the interfiber space takes place more slowly, the larger the number and the less the linear density of the elementary filaments in the complex yarn.Translated from Khimicheskie Volokna, No. 1, pp. 39–41, January–February, 1985.