Some features of spinning viscose fibre and yarns into zinc-free precipitation baths

Conclusions The use of low-acid, bicomponent precipitation baths with additions of urea to the viscose, or also of baths containing such polyvalent metals as aluminum or magnesium, which permits one to obtain a fibre with improved physico-mechanical indices and fatigue properties at the spinning speeds which have been adopted in manufacturing is very promising in spinning viscose fibres and yarns into zinc-free precipitation baths.Replacement of the expensive zinc sulfate by cheaper reagents and the reduction in sulfuric acid consumption upon use of less concentrated precipitation baths permit one to obtain an economical advantage and eliminate the possibility of contaminating the water basin with toxic zinc.Translated from Khimicheskie Volokna, No. 2, pp. 51–53, March–April, 1988.     

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 heat-stable polypropylene fibres and their properties

Conclusions A method has been developed for preparing a modified polypropylene fibre by spinning from a mixture of polypropylene and a small amount of a thermoplastic acrylonitrile copolymer which contains a functional group which forms intermolecular chemical bonds during the fibre preparation process.It has been shown that in the given method of modifying PP fibre, its heat resistance is raised by 40–50°K.Translated from Khimicheskie Volokna, No. 3, pp. 51–52, May–June, 1985.     

Effect of aluminum sulfate content of the precipitation bath on fibre physico-mechanical properties

Conclusions A high-strength fibre is obtained on spinning into precipitation baths containing 30–45 g/liter aluminum sulfate and 65–70 g/liter sulfuric acid, and having a bath density of 1.30–1.31 kg/m³. The relative breaking load of the fibre is 28 cN/tex, its elastic modulus in the wet state is 1380 MPa, and its elongation at break is 16%.At an aluminum sulfate content of 15–17 g/liter in the precipitation bath, an increase in sulfuric acid concentration from 90 to 129 g/liter leads to an increase in relative breaking load and the relative strength of fibre in a loop.Translated from Khimicheskie Volokna, No. 3, pp. 40–41, May–June, 1987.     

Some features of fibre preparation from a copolymer of acrylonitrile with 5-vinyl-2-methylpyridine

Conclusions Increasing the content of ionogenic grups in a copolymer of acrylonitrile with 5-vinyl-2-methylpyridine leads to a change in intermolecular interaction is solutions of the polymer, and this exerts an effect on their rheological properties.The parameters of the process of spinning and fibre strengthening are determined by the composition of the copolymer, a change in fibre properties being observed at a content of active groups in the copolymer which is greater than 40% by wt.Translated from Khimicheskie Volokna, No. 3, pp. 17–19, May–June, 1986.     

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.     

Kinetics of the decomposition of cellulose xanthate in spinning viscose films into sulfuric acid precipitation baths

Conclusions Rate constants for the decomposition reactions of cellulose xanthate have been determined in spinning viscose films into sulfuric acid baths having acid concentrations of 100–1100 g/liter.The data obtained can be used to determine technological parameters in spinning fibres with assigned physico-mechanical characteristics.Translated from Khimicheskie Volokna, No. 5, pp. 37–38, September–October, 1987.     

Effect of synthesis conditions on the viscosity properties of acrylonitrile copolymer spinning solutions

Conclusions The spinning solution used the high-shrinkage component in the manufacture of a bicomponent fibre based on an acrylonitrile copolymer in a structured system and has a weakly defined viscosity anomaly.An increase in initiator content, and also an increase in polymerization temperature, without changing the character of flow of the spinning composition, reduces the molecular weight of the copolymer and the viscosity of the spinning solution.An increase in the sodium thiocyanate content in the water is accompanied by an increase in the molecular weight of the copolymer and in the viscosity of the spinning solution.Translated from Khimicheskie Volokna, No. 6, pp. 15–16, November–December, 1985.     

Mechanism of polyacrylonitrile fibre spinning by the thiocyanate method

Conclusions 1. The process of spinning PAN fibres by the thiocyanate method into baths with various precipitating powers has been studied. The mildness and severity of the baths have been varied by varying the NaSCN concentration from 12 to 24%, and also varying the temperature from 5 to 20°C.2. A dependence of the threshold precipitation concentration on polymer content of the spinning solution has been shown. At a polymer content of 13.5%, the threshold precipitant (water) concentration at which precipitation begins is 63%.3. At NaSCN concentrations above 22–24% in the precipitation bath, a precipitant concentration is established on the surface of the forming fibre at the moment of contact between the spinning solution and the precipitation bath which is below the threshold value, and precipitation begins after a certain time, during the course of which, as a result of diffusion, the precipitant concentration is raised to the threshold level.4. On softening the spinning conditions by increasing the NaSCN concentration in the precipitation bath up to a certain limit, a fibre is formed with a more perfect fibril structure, which ensures obtaining a stronger carbon fibre.5. Extreme softening of the spinning conditions leads to an increase in fibre porosity. The suggestion is advanced that this phenomenon is connected with a change in the mechanism of spinning solution phase breakdown where, along with polymer precipitation in the form of a solid phase, partial precipitation in the form of a liquid phase takes place.Translated from Khimicheskie Volokna, No. 5, pp. 3–7, September–October, 1993.     

Some peculiarities of the copolymer precipitation in spinning a strongly-acid chemisorptive fibre

Conclusions The existence of polyelectrolyte swelling (self-elongation of the fibre on change of medium) has been established in strongly acid undrawn gel-fibre.It has been shown that cementing of the strongly-acid fibre after drying, when the fibre has been wet-spun into aqueous-organic baths, is caused by the presence of solvent which is strongly retained on the fibre.A possible mechanism for the retention of solvent by the strongly-acid gel-fibre has been advanced.Translated from Khimicheskie Volokna, No. 4, pp. 32–34, July–August, 1987.     

Special features in spinning cuprammonium fibres into aqueous-organic baths

Conclusions A number of aqueous—organic baths which are usable in spinning cuprammonium fibres have been studied.It has been shown that the composition, precipitating power of the precipitation bath, and spinning conditions predetermine the physicomechanical properties of cuprammonium fibres.Translated from Khimicheskie Volokna, No. 5, pp. 18–20, September–October, 1984.     

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.     

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.     

Kinetics of change in polymer concentration in spinning viscose yarn

Conclusions A method of investigating the change in polymer concentration in spinning viscose yarns by the wet method as a function of the compositions of the spinning solutions and the precipitation baths has been proposed.Translated from Khimicheskie Volokna, No. 6, pp. 33–35, November–December, 1986.     

Special features in spinning viscose fibre and yarns into a precipitation bath containing sulfuric acid and sodium sulfate

Conclusions The possibility of obtaining a viscose fibre with increased strength up to 25–28 cN/tex, and improved fatigue properties, a low-shrinkage fibre, or a fibre with less loss of strength in the wet state has been demonstrated under experimental conditions. The process of preparing a crimped viscose fibre has been checked out under manufacturing conditions.Eliminating zinc sulfate from the technological process and reducing the specific norms for consumption of sulfuric acid (thanks to the use of precipitation baths which are less concentrated in sulfuric acid) and for neutralizing agents affords an opportunity to reduce contamination of wastewater and to obtain ecological and economic benefits.Translated from Khimicheskie Volokna, No. 6, pp. 16–18, November–December, 1986.     

Effect of urea additions on structure formation during the separation of hydrocellulose from viscose

Conclusions It has been shown by electron microscopy that the formation of two types of structure is possible on spinning model films from viscose into precipitation baths containing additions of urea: finely heterogeneous and cellular.The suggestion has been made that additions of urea to the precipitation bath retard viscose gelation processes.Translated from Khimicheskie Volokna, No. 4, pp. 25–26, July–August, 1986.     

Purification of spinning baths in production of dyed fibers from solutions of polymers

Possible methods of purification of dyes from spinning baths in production of fibers from solutions of polymers were examined. The outlook for the adsorption method of purification of spinning baths and optimum versions of the equipment formulation were demonstrated.All-Russian Scientific-Research Institute of Synthetic Fibers, Tver'. Translated from Khimicheskie Volokna, No. 4, pp. 22–26, July–August, 1992.     

Preparation of a chemisorptive sulfonate fibre and its properties

Conclusions Conditions have been developed for preparation of a chemisorptive fibre containing sulfonate groups from an acrylonitrile-sodium methallylsulfonate copolymer which processes satisfactorily into textile articles.During the process of orientation stretch of the fibre prepared, strengthening takes place as a result of orientation of the acrylonitrile component.Translated from Khimicheskie Volokna, No. 4, pp. 8–9, July–August, 1988.     

Hollow fibres for baromembrane separation of liquids

Hollow fibres for reverse osmosis are spun from solutions of polymers in mixtures of a solvent with a swelling agent; the solvent must have a higher vapor pressure than the swelling agent and must evaporate in the preforming stage to prevent formation of a layer of highly concentrated solution on the outside of the liquid fibre which decomposes into phases according to a spinodal mechanism on entering the spinning bath. The layers of the solution near the center of the liquid fibre decompose into phases according to a nucleation mechanism. After hydrothermal treatment (annealing), a hollow fibre with a wall of asymmetric structure is formed, and the surface layer only has diffusion permeability while the layer nearer the center of the fibre has phase permeability. In order to increase the permeability of the ultrafiltration fibre and fibre matrix for reverse osmosis, the precipitating agent must primarily diffuse inside the jet of spinning solution during spinning.All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna. No. 2, pp. 3–11. March–April. 1996.     

Effect of surface-active substances on the fibre-forming process and properties of nitron fibre

Conclusions The effect of surface-active agents on the surface tension of polyacrylonitrile (PAN) spinning solutions has been studied.It has been found that introducing SAS into the precipitation bath increases fibre-formation stability. The use of SAS as modifying additives to the spinning solution and into the precipitation bath leads to an increase in the uniformity of spun fibre properties.The possibility of reducing the linear density of Nitron fibres on introducing SAS into the spinning solution and the precipitation bath has been demonstrated.Translated from Khimicheskie Volokna, No. 3, pp. 24–26, May–June, 1985.