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.     

Resonance and fibre formation in the process of spinning melts of flexible-chain polymers

Conclusions The reason for onset of the polymer jet stretch resonance phenomenon during the spinning process has been found.A mechanism for the uniaxial stretching of a jet of viscoelastic liquid under conditions of fibre stretching resonance has been proposed.Some features in the spinning of a polycaproamide melt have been determined.This article was published to stimulate discussion.Translated from Khimicheskie Volokna, No. 1, pp. 24–26, January–February, 1990.     

Preparation of reinforced composite yarns based on polymer mixtures

Conclusions The possibility has been demonstrated of preparing self-reinforcing composite fibres on spinning the following mixtures from the melt: polycaproamide—polyoxymethylene; copolyamide—polyoxymethylene; or an ethylene—vinylacetate copolymer—polyoxymethylene, due to the formation of ultrathin polyoxymethylene fibres in the bulk of the other polymer on flow of the mixture melt. Because of the presence of microfibres, an increase in the orientation stretch ratio of the composite fibre is observed, plus a synergistic increase in its strength and initial modulus.In articles from polymer mixtures with a well-developed interfacial layer and a strong interaction of the components in it, the maximum reinforcement will take place only at a low (up to 10%) content of the disperse phase polymer. In the absence of a strong interaction, the maximum reinforcing effect is observed when there is a predominant formation of ultrathin fibres of continuous length by the disperse phase polymer.The presence of films decreases the rise in strength and modulus of the composite fibre to a greater extent than the presence of short fibres.Translated from Khimicheskie Volokna, No. 3, pp. 35–37, May–June, 1984.     

Effect of stabilization and plasticization on the molecular weight distribution of cellulose triacetate in spinning fibres from a melt

Conclusions The molecular weight distribution of cellulose triacetate before and after spinning fibres from the melt has been investigated.It has been shown that the introduction of a stabilizer or plasticizer into the starting polymer composition leads to a decrease in the extent of polymer macromolecule degradation in spinning fibres from the melt and to an increase in the mean degree of polymerization.Translated from Khimicheskie Volokna, No. 1, pp. 42–43, January–February, 1987.     

Some features of spinning hollow fibres from polycarbonatesiloxane melts

Conclusions The following parameters have been determined as a result of calculations: fibre tension, solidification path length, and the change along the spinning path of the following: stretching stresses, speed, radius, wall thickness, and fibre temperature.It has been shown that, with increase in take-up speed, the length of the section of fibre deformation is reduced, varying practically proportionally to the flow rate of the polymer system.Stability of the process of spinning hollow fibres from polycarbonatesiloxane melts is assured within a narrow range of stretching force.Translated from Khimicheskie Volokna, No. 3, pp. 41–43, May–June, 1989.     

Laws governing the process of spinning isotropic pitches

Conclusions -- A procedure has been developed for calculating the specific volume of the flowing zone of fibre in spinning from the melt.-- The unequivocal connection between the specific volume of the flowing zone of spun fibre and the strength of the final fibre from pitches indicates that to attain higher strength, it is necessary to create more severe conditions for fibre cooling.-- It has been found that fibres from pitches with a softening point above 200°C are more sensitive to fluctuations in parameters of the spinning process.VNIIPV. Translated from Khimicheskie Volokna, No. 3, pp. 41–42, May–June, 1991.     

Isothermal stretching of the jet of polymer melt in aerodynamic fibre spinning

Conclusions Equations have been obtained for determining the diameter of a polymer melt jet over the length of the isothermal section, which is the zone of spinning fibre by the aerodynamic method.A comparison of the results of calculations with experimental data shows that they agree satisfactorily.Translated from Khimicheskie Volokna, No. 2, pp. 18–19, March–April, 1988.     

Nonisothermal flow of polymer melts and solutions in spinneret channels

Conclusions The effect of dissipation of mechanical energy on the temperature fields of polymer melts and solutions in the channels of spinnerets for fibre spinning has been investigated.It has been shown that the flow of polymer melts in spinneret channels takes place with only slight heat evolution, that is, practically under isothermal conditions. The flow of polymer solutions takes place significantly under nonisothermal conditions, with a large drop in temperature over the channel radius.Translated from Khimicheskie Volokna, No. 4, pp. 42–44, July–August, 1986.     

Chemical changes in polyvinyl fluoride during the process of fibre-spinning

Conclusions The change in some properties of polyvinyl fluoride during the process of fibre spinning has been investigated.It has been found that during the process of converting PVF powder into fibre, the degree of polymer crystallinity plus its resistance to thermal and thermooxidative degradation is increased; depending on the spinning regime, the densities and physicomechanical properties of PVF fibres are different.Translated from Khimicheskie Volokna, No. 4, pp. 34–35, July–August, 1984.     

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.     

Effect of fluctuations in polymer melt temperature of linear density of yarn

Conclusions The effect of polymer melt temperature fluctuation at the inlet to the metering pump on nonuniformity in yarn linear density has been studied.It has been shown that considerable fluctuation in yarn linear density, caused by change in melt temperature, takes place also in individual working sites.A considerable difference in the temperature of the melt going to individual working sites of machines for spinning technical yarns has been discovered.Fluctuation in the linear density of yarn caused by variation in melt temperature at the inlet to the metering pump may reach 0.3–0.8% in spinning technical yarns, depending on the construction (group or individual) of the spinning machine melting devices.Translated from Khimicheskie Volokna, No. 5, pp. 45–47, September–October, 1984.     

Determination of acid impurity content in spinning solution and in freshly spun fibre made from aromatic polyamides

Conclusions The spinning solution from the manufacture of fibre from an aromatic polyamide contains dissolved HCl in the free form and HCl bonded to functional groups of the polymer; the freshly spun fibre contains only bonded HCl.A procedure has been developed for determining the content of free and bound HCl in spinning solution and freshly spun fibre; it is based on titrating a sample of a specimen in a medium of dimethylacetamide containing 3% LiCl with an approximately 0.04-molar alcoholic KOH solution.Translated from Khimicheskie Volokna, No. 2, pp. 58–60, March–April, 1990.     

Change in molecular weight characteristics of an aromatic copolyamide during the polycondensation process

Conclusions The change in molecular weight characteristics and in viscosimetric data during the synthesis process of an aromatic copolyamide has been analyzed. It has been found that, with rise in the degree of completion of the reaction, at definite molecular weight values the dynamic viscosity rises sharply, which indicates the presence of a significant structural component of this system.The effect of polymer molecular weight on fibre physicomechanical properties has been shown. An increase in fibre strength has been noted on increase in molecular weight from 5400 to 7300. The impairment in physicomechanical properties on further increase in polymer molecular weight is connected with difficulties in processing the strongly structured spinning solutions. Processing polymer with a high molecular weight, and, as a consequence, with an elevated dynamic viscosity requires new approaches both to spinning conditions and, possibly, also to synthesis conditions.Translated from Khimicheskie Volokna, No. 2, pp. 29–30, March–April, 1989.     

Dry-spinning fibres from solutions of polymers in high-boiling solvents

Conclusion Dry spinning from polymer solutions in high-boiling solvents is used extensively for the production of polyacylonitrile, polyurethan, and thermostable fibres of various classes. The method possesses important economic advantages over wet spinning, i.e., the concentration of the spinning solution and the spinning speeds are higher, and solvent recovery is easier and more complete.The dry method is preferred for polyurethan fibre, polyacrylonitrile filament, and fibres based on poly-m-phenylene isophthalamide, polybenzimidazoles, polyamidoimides, and polyimides because it gives better physicomechanical fibre properties.The spinning speed for these fibres does normally exceed 300 m/min although speeds of 800–1000 m/min have been reported as practicable.The quality of the finished fibres is influenced to a significant extent by the configuration of the spinning equipment (i.e., the cabinet design and the method of distributing the gas-air flow) and by the substances added to the spinning solution (esters of phosphoric acid, organosilicon compounds, etc.).All-Union Scientific-Research Institute for Man-Made Fibres. Translated from Khimicheskie Volokna, No. 1, pp.11–17, January–February, 1976.     

Diffusion processes in spinning polyacrylonitrile fibres

Conclusions -- It has been found that the diffusion coefficient of precipitant into polyacrylonitrile fibre being spun at 20°C is 0.8·10^–5 cm²/sec.-- The distribution of precipitant concentrations in fibre spun from solutions of polyacrylonitrile into an aqueous thiocyanate precipitation bath has been obtained.-- The extent of the polymer precipitation zone in a jet of spinning solution has been estimated.Translated from Khimicheskie Volokna, No. 5, pp. 6–8, September–October, 1990.     

The use of electrically heated melt-spinning heads having forced polymer feed on spinning machines for synthetic fibres

Conclusions The operation of electrically heated melt-spinning heads with forced polymer feed has been investigated on machines for spinning low thread-number Capron fibre.All-Union Research Institute for Synthetic Fibre Plant (VNIIMSV), Chernigov. Chernigov Factory. Translated from Khimicheskie Volokna, No. 6, pp. 50–52, November–December, 1969.     

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.     

Structure of a biocatalyst fibre containing modified β-galactosidase

Conclusions A connection between the composition of the spinning solution intended for preparation of a biocatalyst fibre, the conditions of fibre spinning, and the porosity characteristics of the fibre structure has been established.The possibility of purposefully regulating the catalytic properties of a biocatalyst fibre by varying the fibre structure has been demonstrated.Translated from Khimicheskie Volokna, No. 1, pp. 21–23, January–February, 1989.     

Some features of the flow of a polypropylene melt in the formation of fibres

Conclusions 1. On passing through a spinneret orifice, a polypropylene melt behaves as a structured pseudoplastic liquid and its properties are described by flow laws analogous to the flow laws in a capillary viscometer.2. The dependence of the effective viscosity of a polypropylene melt on its molecular weight, temperature, and shear stress has been established in the form of a semiempirical equation.3. The effective viscosities of a polypropylene melt on flow through spinneret orifices in the formation of a fibre have been determined. It has been shown that a change in the effective viscosity does not affect the properties of the fibre.(VNIIV) All-Union Scientific Research Institute for Synthetic Fibres. Translated from Khimicheskie Volokna, No. 2, pp. 14–16, March–April, 1969.     

Polycaproamide fibres with reduced combustibility

Conclusions The basic characteristics of the composition of polycaproamide fibres in the presence of various phosphorus-containing compounds, introduced into the polymer melt before spinning, have been investigated.It has been shown that it is most advisable to use borofos or the complex salt of an alkylphosphonic acid with antimony for flameproofing polycaproamide fibres; these markedly reduce the rate of temperature range of decomposition by causing intensive coke formation by the polymer.Translated from Khimicheskie Volokna, No. 3, pp. 14–15, May–June, 1988.