Complex Yarns Research Articles

Use of cloth from synthetic fibres to clean up (filter) epoxy resins

In the filtration of technological solutions of epoxy resins, one can use cloths based on polyamide, polyester, or polypropylene complex yarn, having 290–420 open (interfilament) pores per cm2 and through porosity of 5–22%; these have a low hydraulic resistance and permit one to attain the best filtrate quality. They can successfully replace the types of cloths from natural fibres which are being used at present.

Estimation of the scale effect in mechanical testing of technical yarns

On the basis of the statistical theory of strength, a scale effect equation has been formulated for technical complex yarns, on approximation of strength tests by a logarithmically normal distribution.

Use of diluted viscose waste in the process of preparing complex yarn for aircraft fabrics

The possibility has been established of using dilute viscose wastes in the process of preparing a spinning solution for spinning complex viscose yarns which are used in the manufacture of aircraft fabrics.

Estimating the character of the distribution in mechanical properties of technical complex yarns

The possibility of approximating the results of strength (breaking load) tests by the normal, logarithmically normal, or Weibull distribution has been shown in the case of technical complex yarns from various methods of preparation, having various levels of defectiveness. The best confirmity of the experimental data to the three-parameter Weibull distribution has been noted.

Calculation of the process of multistage complex yarn washing

On the basis of kinetic relationships and the squeeze-out material balance equation, a procedure has been developed for calculating a multistage process for the continuous washing of a complex yarn.

Determination of the shear modulus of yarns in twisting

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.

Effect of physically active media on yarn orientation strengthening

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.

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

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.

Changes in the properties of Ovilan fibre during the texturizing process

Before untwisting, a complex viscose yarn consists of a set of variously crimped elementary filaments with nonidentical degrees of extensibility and crimp.

Effect of the structure of the elementary filaments on the tension of complex viscose yarns during drying

The effect of the structure of the elementary filaments on the tension of a complex viscose yarn during drying has been investigated.

Mathematical description of the mass-exchange processes in a vibrational apparatus for washing complex yarns

An experimental and theoretical study has been made of mass-exchange processes in a vibrational apparatus for washing complex yarns. A mathematical description of the process has been set up, with use of the solution obtained for the differential equation for nonstationary diffusion at nonzero initial conditions. A numerical method of calculating mass-exchange processes for a separated complex yarn moving in a countercurrent stream of liquid has been developed; this has been used to determine the length of a vibrational apparatus.

Some special features in drying ordinary viscose textile yarns

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.

Special features in spinning fine viscose textile yarns

Conditions which assure stability of the process of spinning a complex viscose yarn with an increased number of elementary filaments have been determined.

Determination of the viscoelasticity of polyamide yarns over a wide tension range

A method of determining the deformation characteristics of polycaproamide complex yarns over a wide range of extension (4–8%) by short-term measurement of the parameters of the relaxation process has been developed. A modernization of the determining nonlinear viscoelasticity equation has been carried out, and a procedure based on it has been developed for the calculated prediction of stretching diagrams over a wide range of extension at an assigned rate. It is also recommended to use the procedure developed for the mathematical description of more complex deformation regimes.

Viscose textile yarns from the continuous production method with improved consumer properties

Moisture transfer has been studied in viscose textile complex yarns having a linear density of 13.3 tex where the linear density of the elementary filaments was 0.13–0.75 tex, as compared with moisture transfer in cotton, natural silk, and polyamide yarns.

Effect of linear density of elementary viscose filaments on the properties of complex yarns and fabrics made from them

A decrease in the linear density of the elementary filaments essentially does not affect the physicomechanical properties of complex viscose yarns. However, with decrease in the linear density of the elementary filaments, important changes are observed in properties which determine their wear resistance; durability against repeated double bends is increased, but the resistance to abrasion is reduced. The use of complex viscose yarns having a reduced elementary filament linear density aids in the preparation of fabrics with greater covering power, which creates conditions for reducing the volume of material.

Estimating the acid concentration in spinning viscose complex yarn through a spinneret with a large number of holes

Estimating the acid concentration in spinning viscose complex yarn through a spinneret with a large number of holes

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

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.

Evaluation of the coefficient of utilization of the strength of elementary fibres in a complex yarn from the positions of the statistical theory of strength

The statistical strength theory has been applied to analysis of the phenomenon of breakage of a complex yarn in one-time extension. An equation has been obtained in which a connection has been established between the coefficient of utilization of the strength of the elementary fibres in a complex yarn and the Weibull parameter, which characterizes the scatter in the figures.

Effect of the linear density of the elementary filaments on the properties of viscose complex yarns prepared by the centrifugal method

Effect of the linear density of the elementary filaments on the properties of viscose complex yarns prepared by the centrifugal method