Preparation of heat-bonded fibrous materials with an assigned air-permeability from polymer melts

Conclusions A directly proportional dependence of the air-permeability of heat-bonded fibrous materials from the aerodynamic spinning method on fibre diameter has been found, plus an inverse proportionality on the cloth thickness, wherein the cloth thickness exerts a greater effect on air-permeability.The fundamental possibility of predicting the air-permeability of heat-bonded fibrous materials from the aerodynamic spinning method having a known fibre diameter and cloth thickness has been shown, and also the possibility of preparing materials with an assigned air-permeability by regulating the ratio of fibre diameter to cloth thickness.Translated from Khimicheskie Volokna, No. 3, pp. 57–59, May–June, 1989.     

Comparative evaluation of acoustical properties of heat-bonded and needle-punched fibrous materials prepared from polymer melts

Conclusions The acoustical properties of heat-bonded and needle-punched fibrous materials have been studied by the steady-state method.The basic structural and technological parameters which affect the sound-absorption coefficient of these materials have been established.It has been shown that heat-bonded fibrous materials have advantages over the needle-punched ones, since they ensure an equal sound-absorption coefficient at a lower thickness.Translated from Khimicheskie Volokna, No. 6, pp. 27–28, November–December, 1989.     

Determination of the porosity of fibrous cloth spun by a one-stage method from a polymer melt

Conclusions The effect of technological parameters in the aerodynamic spinning process on the integral mean size of pores in heat-bounded fibrous materials has been studied.A model has been obtained for determining the basic pores of a heat-bonded fibrous fabric for the case of dense networks of straightened-out fibres.Translated from Khimicheskie Volokna, No. 2, pp. 43–44, March–April, 1989.     

A heat-bonded fibrous material from polyethylene

Conclusions The fundamental possibility of preparing a heat-bonded fibrous material from polyethylene has been established.It has been found that a heat-bonded fibrous material from polyethylene is inferior in basic consumer properties to material from copolyamide.It is recommended to use heat-bonded material from polyethylene for joining fabrics in the sewing industry.Translated from Khimicheskie Volokna, No. 1, pp. 32–33, January–February, 1990.     

Effect of aerodynamic spinning parameters and polymer properties on fibre diameter

Conclusions On the basis of theoretical calculations by a mathematical model of the process of aerodynamic spinning of polymer melts, whose adequacy has been established from experimental data, the sensitivity of final fibre diameters to change in technological spinning parameters and on the thermophysical and rheological properties of the polymer has been determined.It has been shown that among the factors which most significantly affect the final fibre diameter are the velocity of air movement in the ejector, the polymer flow rate, the temperature of the melt, the density of the melt, the viscosity anomaly, and the activation energy of viscous flow.Translated from Khimicheskie Volokna, No. 5, pp. 37–39, September–October, 1988.     

Dynamic characteristics of the high-speed process of spinning polymer melts

Conclusions A procedure has been given for calculating the instability in fibre diameter under the action of technological perturbations, which is based on the use of the dynamic characteristics of high-speed process of spinning polymer melts.It has been shown that the reaction of the high-speed spinning system to stepwise perturbations is less than the reaction to harmonic perturbations at the inherent frequency of the spinning system. The range of perturbation frequencies which adjoins the inherent frequency of the spinning system is very dangerous from the point of view of instabiity in the diameter of the spun fibres.The possibility of using dynamic characteristics to base requirements on accuracy in stabilization of technological parameters in the high-speed spinning process has been examined.Translated from Khimicheskie Volokna, No. 5, pp. 13–15, September–October, 1989.     

External aerodynamics in the process of preparing fibrous materials by the one-step method

Conclusions The interconnection between the coefficient of friction and the significant parameters of external flow past the elementary filaments in the case of aerodynamic spinning has been found by the method of dimensional analysis.An equation has been found which is recommended for the calculation of the mean coefficient of friction in spinning polyamide, polyester, and polypropylene thermally bonded fibrous materials by the aerodynamic method, with allowance for the number of elementary filaments in the bundle.Translated from Khimicheskie Volokna, No. 2, pp. 14–16, March–April, 1988.     

Improving the properties of fibrous materials prepared by the aerodynamic spinning method

Conclusions It has been shown that fibrous materials from yarns having a six-armed profile or a six-armed profile with an interior cavity have 1.3 times greater strength as compared with material from round yarns at an equal surface density.Mathematical expressions which have been obtained make it possible to calculate the technological needle-punching parameters which ensure obtaining fibrous materials from profiled yarns with the maximum possible strength.Translated from Khimicheskie Volokna, No. 4, pp. 37–38, July–August, 1986.     

Sound-absorbing properties of fibrous materials prepared by the aerodynamic method

Conclusions An equation has been obtained for determining the sound-absorption coefficient of fibrous materials as a function of the frequency of the directed sound and of the structural parameters of the sound-absorbing obstacle used.An estimate has been made of the extent of effect of structural parameters of fibrous materials on the maximum sound-absorption coefficient.Translated from Khimicheskie Volokna, No. 5, pp. 22–24, September–October, 1989.     

Effect of technological spinning transitions on the properties of nickel-containing nitron fibre

Conclusions The effect of technological spinning transitions on the properties of an electrically-conducting metallized Nitron fibre has been investigated.It has been shown that in mechanical crimping the mechanical and electrically-conducting properties of a nickel-containing fibre are considerably impaired. During the spinning process, a considerable leveling out of the nickel content of the fibre and of its electrical resistance takes place.Processing of the nickel-containing fibre should be carried out with elimination of the mechanical crimping process. Thereupon the change in fibre properties takes place mainly during the process of preparing the combed lap.Translated from Khimicheskie Volokna, No. 5, pp. 39–40, September–October, 1985.     

Cooling of the polymer jet in fibre spinning

Conclusions The effect of various technological parameters (jet stretch ratio, temperature and flow rate of the polymer melt, temperature and velocity of the air which cools the melt, and rheological characteristics of the polymer) on the change in temperature and viscosity of the polymer jet along the length of the spinning zone has been investigated.It has been shown that the temperature of the cooling air, the Stanton number, and the velocity of the cooling air exert the greatest effect on the fibre temperature at the take-up device, but jet stretch ratio and rheological properties of the melt affect fibre temperature only slightly.Translated from Khimicheskie Volokna, No. 6, pp. 19–20, November–December, 1987.     

Optimization of the spinning solution preparation process in the manufacture of polyvinyl chloride fibre

Conclusions The effect of spinning solution preparation parameters on the fibre preparation process and on the properties of polyvinyl chloride fibre have been studied using the experiment planning method.It has been found that the concentration and holding time of the spinning solution exert the greatest effect on the process of washing the fibre free of dimethylformamide.An optimization of the parameters of preparing a solution for polyvinyl chloride fibre production under manufacturing conditions has been carried out.Translated from Khimicheskie Volokna, No. 1, pp. 24–25, January–February, 1988.     

Air-permeability of fibrous materials prepared by aerodynamic spinning from polymer melts

Conclusions The procedure for determining the air-permeability of fibrous materials has been improved.The air-permeability of a wide assortment of nonwoven materials prepared by the aerodynamic spinning method has been characterized.Translated from Khimicheskie Volokna, No. 1, pp. 43–45, January–February, 1989.     

Effect of orientation stretch and of jet stretch on properties of viscose fibre spun into a bicomponent precipitation bath

Conclusions The effect of orientation stretch and of jet stretch on the technological process of preparing viscose fibre from viscoses containing added urea has been studied in spinning into a bicomponent precipitation bath containing sulfuric acid and sodium sulfate.It has been shown that increasing the air stretch to 30–40% while reducing the sulfuric acid content of the precipitation bath to 80–100 g/liter and reducing the jet stretch 8 to 20% helps to improve the properties of viscose fibre.Translated from Khimicheskie Volokna, No. 4, pp. 47–48, July–August, 1989.     

Mathematical model of aerodynamic,high-temperature spinning of fibres in fabrication of nonwoven materials

A mathematical model of steady-state aerodynamic spinning of fibres from a melt in fabrication of nonwoven materials was developed. The rate, longitudinal velocity gradient, diameter, and temperature of the spun fibre were calculated and are in satisfactory agreement with the experimental data. The forces acting on the fibre during aerodynamic spinning were calculated. It was shown that the character of the change in the aerodynamic force differs significantly from the classic method of spinning.All-Russian Scientific-Research Institute of Synthetic Fibres, Tver'. Translated from Khimicheskie Volokna, No. 6, pp. 39–41, November–December, 1993.     

A study of nonuniformity in polyacrylonitrile yarns

Conclusions Nonuniformity of elementary filaments in the spinning of polyacrylonitrile yarns has been studied. It has been shown that the spinning conditions (spinneret hole diameter, concentration and temperature of the precipitation bath) have only a slight effect on the nonuniformity of elementary filaments.Nonuniformity rises along the course of the technological process.The suggestion has been made that the increase in nonuniformity of elementary filaments with respect to diameter is connected with structural nonuniformity in the freshly spun fibres and with the presence of gel particles in the spinning solutions, which lead to an increase in nonuniformity during stretching.Translated from Khimicheskie Volokna, No. 1, pp. 38–39, January–February, 1990.     

Use of fibrous polyamide material in road construction

Conclusions The possibility of using fibrous materials based on waste from the manufacture of polyamide fibre in road construction has been examined.The effect of the acidity of the medium on the lifetime of fibrous polyamide material has been established.Translated from Khimicheskie Volokna, No. 1, pp. 34–35, January–February, 1984.     

Some features of spinning cuprammonium fibres into precipitation baths containing calcium salts

Conclusions On the basis of data on precipitating power and the rate of dehydration of cuprammonium solutions of cellulose, the fundamental possibility has been demonstrated of spinning fibres from such solutions into precipitation baths containing calcium salts, using the technological scheme for viscose fibre manufacture.The dependence of the basic characteristics of the freshly-spun fibre on calcium salt content and temperature of the precipitation bath has been found.Moscow Textile Institute. Translated from Khimicheskie Volokna, No. 1, pp. 11–13, January–February, 1987.     

Preparation of ftorlon fibre filled with manganese dioxide

Conclusions The possibility of obtaining catalytic fibres by introducing the catalyst as a filler into the structure of Ftorlon fibre has been established.Sorptive properties of Ftorlon fibre spun in the absence of filler as a function of the amount of polyethylene glycol added to a spinning solution of the fibre-forming polymer and of the spinning conditions have been investigated, as well as the morphology of the surface of the modified Ftorlon fibre.It has been discovered that, by choosing the composition of the spinning solution and the conditions of spinning Ftorlon fibre filled with manganese dioxide, it is possible to obtain a fibre having a porous structure which ensures accessibility of the filler to reagents.Translated from Khimicheskie Volokna, No. 2, pp. 31–33, March–April, 1988.     

Preparation of fibres from graft copolymers of acrylonitrile and polyvinyl alcohol

Conclusions The possibility of spinning fibres from graft copolymers of polyvinyl alcohol and acryonitrile by the scheme for spinning polyacrylonitrile fibre has been established.It has been shown that spinning solutions can be prepared directly from latexes of the graft copolymers.The suggestion has been made that long side chains in the copolymers participate in formation of supermolecular structural elements and aid in obtaining fibres with adequately high mechanical strength and an increased thermal stability.Translated from Khimicheskie Volokna, No. 1, pp. 13–15, January–February, 1988.