Colorimetric determination of formaldehyde content of cellulose film

Conclusions -- A selective and rapid colorimetric procedure has been developed for determining formaldehyde content in aqueous extracts of cellulose film.-- Metrological characteristics of the procedure in the formaldehyde concentration range 0.02–0.16 mg/liter have been found. The detection limit is 0.016 mg/liter of formaldehyde.Translated from Khimicheskie Volokna, No. 5, pp. 57–58, September–October, 1991.     

Application of the turbidimetric titration method to study the molecular-weight distribution of sulfite cellulose in acetylation

Conclusions -- It is recommended to the central plant laboratories of man-made fibres to use the method of turbidimetric titration to determine the molecular-weight distribution of sulfite cellulose in the process of working it up.-- A rapid method has been developed for determining a molecular-weight distribution of sulfite cellulose for acetylation using a selective solvent—precipitant system.Translated from Khimicheskie Volokna, No. 6, pp. 36–38, November–December, 1990.     

Determination of the content of residual organic solvents in biocatalyst fibres by vapor-phase chromatographic analysis

Conclusions -- A procedure of vapor-phase gas-chromatographic analysis has been developed for determining the content of residual organic solvents in biocatalyst fibres.-- The method has been tested in a number of lots of biocatalyst fibres.-- The method has passed through metrological certification.Translated from Khimicheskie Volokna, No. 6, pp. 55–56, November–December, 1990.     

Modeling processes of the high-speed spinning of viscoelastic polymer melts allowing for the total force balance

Conclusions -- An effective procedure has been proposed for modeling the process of high-speed spinning of viscoelastic polymer melts, which permits one to correctly and rather simply take into account the forces acting on the polymer jet.-- The contribution of forces from aerodynamic resistance, inertia, and gravity to the total force balance has been evaluated. The character of jet deformation in high-speed spinning has been examined and possibilities for regulating it by changing technological parameters have been indicated.Translated from Khimicheskie Volokna, No. 6, pp. 21–23, November–December, 1990.     

Procedure for the polarographic determination of bound formaldehyde content in cellulose acetates

Conclusions -- A procedure has been developed for the polarographic determination of the bound formaldehyde content of cellulose acetates prepared by the high-temperature homogeneous cellulose acetylation method involving the use of a cross-linking agent.-- The use of this procedure is recommended for determining the bound formaldehyde content of cellulose acetates from various production operations and also in acetate fibres.Translated from Khimicheskie Volokna, No. 5, pp. 58–60, September–October, 1991.     

Preparation of polyolefin fibres

Conclusions 1. A procedure has been developed for obtaining low-stretch, high-denier (bulk-braided) thread from polypropylene and fibrillated film from polyolefins (propylene and polyethylene) for manufacturing carpets. Fibrillated film is also used for making bagging and twisted-thread artefacts.2. A method has been developed for strengthening polypropylene fibre at temperatures above the melting point of the unoriented polymer; this makes it possible to obtain high-strength fibre.All-Union Scientific Research Institute for Synthetic Fibres (VNIIV). Translated from Khimicheskie Volokna, No. 5, pp. 11–12, September–October, 1969.     

Cooling yarns spun from polymer melts

Conclusions -- The effect of the component air streams on yarn uniformity with respect to linear density has been established. This has afforded opportunity to find an optimum regime for yarn cooling in spinning from polymer melts. Analysis of the pulsations in air streams has made it possible to determine the basic sources for their origin and ways to reduce them.-- A manufacturing control of the yarn cooling regime using anemometers has been proposed.-- A way of intensifying the yarn cooling regime using an air jet on the yarn section after its initial hardening has been described.-- It is recommended to use the method of investigating the process of yarn spinning by analysis of the component air streams in preparing fibres from polymer melts on any type of spinning equipment.Translated from Khimicheskie Volokna, No. 4, pp. 26–30, July–August, 1990.     

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.     

Preparation of poly-m-benzamide and fibres based on this compound

Conclusions 1. The authors have studied the principal laws of polycondensation of the hydrochloride of m-aminobenzoyl chloride. A polymer with a logarithmic viscosity of 0.7–0.9 has been obtained by the procedure developed.2. It has been established that poly-m-benzamide is an amorphous polymer with a glass-transition temperature of about 300°C. The weight loss of the polymer at 500°C is 2.5–3.5%.3. Fibre with a breaking length of 36 rkm (breaking length expressed in kilometers), high-heat resistance, and excellent thermal stability has been formed from solutions of the polymer.All-Union Scientific-Research Institute for Synthetic Fibres (VNIIV). Translated from Khimicheskie Volokna, No. 5, pp. 2–4, September–October, 1969.     

An express method for determining inorganic impurities in polycaproamide

Conclusions 1. A procedure has been developed for determining inorganic impurities in a polyamide crumb which permits the time of analysis to be shortened from 6–7 to 30–40 min.2. The method can be used for the qualitative determination of impurities in the polymer in the inspection of the production of Capron fibre and for the semiquantitative determination of titanium in the matted polymer.Daugavpils Factory. Translated from Khimicheskie Volokna, No. 3, pp. 67–68, May–June, 1969.     

Quantitative monitoring of polyethylene glycol in aqueous dimethyl acetamide mixtures in the manufacture of synthetic fibres

Conclusions -- A photometric procedure has been developed for the quantitative determination of the PEG (5000) content in precipitation bath solutions and technological solutions in the manufacture of synthetic fibres.-- Metrological characteristics of the procedure have been calculated.-- Equations have been given which describe the linear calibration curve for determining PEG (5000) in various aqueous dimethyl acetamide mixtures.Translated from Khimicheskie Volokna, No. 5, pp. 60–62, September–October, 1990.     

Effect of precipitation conditions on phase equilibrium and the structure of polyacrylonitrile isolated from solutions

Conclusions -- A phase-equilibrium diagram has been obtained for the system polyacrylonitrile-dimethyl sulfoxide-isopropyl alcohol, which permits one to determine the composition of phases in the isolation of polymer from solution.-- It has been shown that the precipitation thresholds decrease with increase in the isopropyl alcohol content of the precipitation bath and with increase in polymer concentration in the spinning solution.-- The correlation has been shown between the change in structure parameters of polyacrylonitrile isolated from solutions by the wet method and the polymer precipitation conditions, which are characterized by the concentration of the starting solution and the composition of the precipitation baths.VNIIPV, Urals Branch, Sverdlovsk. Translated from Khimicheskie Volokna, No. 3, pp. 17–18, May–June, 1991.     

Investigating the process of washing out sodium thiocyanate from polyacrylonitrile tows

Conclusions -- A procedure has been developed for determining the diffusion coefficient of sodium thiocyanate in freshly formed PAN tow during wash-out which is based on refractometry.-- The temperature dependence of the diffusion coefficient of NaSCN has been investigated using a thermostattable cuvette.-- The distribution of NaSCN concentrations in PAN tow during the process of wash-out has been given.Translated from Khimicheskie Volokna, No. 6, pp. 25–26, November–December, 1990.     

Selection of microporous adsorbents for the clean-up of manufacturing waste water

Conclusions -- A procedure has been developed for selecting microporous sorbents for the clean-up of waste water, which takes into account overall the diverse technological characteristics of adsorbers.-- The procedure has been checked out as applicable to selecting carbon sorbents for cleaning up caprolactam-containing waste water in the manufacture of polyamide fibres.Translated from Khimicheskie Volokna, No. 5, pp. 24–27, September–October, 1990.     

Determination of stresses in a package of textile yarn

Conclusions -- A method has been developed for determining stresses in a package of textile yarn and, based on it, an instrument has been constructed for measuring this parameter.-- Using the instrument developed, stresses have been measured in the end zones of a biconical package. A quantitative estimate has been obtained for the end anisotropy of the package and measures have been noted which are aimed at improving the quality of the winding body.Translated from Khimicheskie Volokna, No. 6, pp. 46–48, November–December, 1990.     

Preparation of polymer solutions which are free of suspended mechanical particles

Conclusions -- A method of preparing low-concentration polymer solutions which are free of suspended particles in measurements of the molecular characteristics by the light-scattering method has been described.-- The system presented permits one to prepare such solutions directly in the measuring cuvette with monitoring of the concentration and size of residual particles simultaneously with the clean-up.-- Kinetic dependences of concentration and of mean residual particle size on duration of clean-up have been obtained.Translated from Khimicheskie Volokna, No. 5, pp. 3–5, September–October, 1990.     

A fragment of the phase diagram of polysulfone in dimethyl acetamide

Conclusions -- The temperature—concentration limits of the solubility of PS in DMAc have been determined, and it has been shown that the solubility increases with rise in temperature.-- The phase breakdown of solutions of PS in DMAc has been identified as amorphous without the intervention of crystallization.-- A fragment of the phase diagram for the ternary system PS-DMAc-H₂O shows that the region of solutions is strongly narrowed on increasing the concentration of the polymer.Translated from Khimicheskie Volokna, No. 4, pp. 20–21, July–August, 1990.     

Use of high-performance liquid-chromatography to determine the metal content of waste water

Conclusions -- A procedure has been developed with a simultaneous determination of Co, Ni, and Cu in waste water, using the Milikhrom microcolumn chromatograph.-- The procedure is simple and rapid (analysis time, 20 min); it eliminates the stage of extraction of the chelates, and is comparable in sensitivity with the atomic-absorption spectrophotometry method.Klinskii Khimvolokno PO. Translated from Khimicheskie Volokna, No. 5, pp. 54–55, September–October, 1992.     

Accelerated determination of the viscosity of poly-p-phenylene terephthalamide

Conclusions A procedure has been proposed for determining the viscosity of dilute PPTA solutions which is based on dissolving the reaction mixture formed in the polymer synthesis process in sulfuric acid.The procedure makes it possible to considerably shorten (by a factor of 10) the time for determining the viscosity of PPTA solutions.Translated from Khimicheskie Volokna, No. 3, pp. 31–32, May–June, 1985.     

Identification and quantitative determination of low-molecular-weight compounds and precipitation and plasticizing baths,and the effect of monomer-and solvent-contamination on their composition

Conclusions -- Using the liquid-chromatography method, a selective procedure has been developed for the quantitative determination of low-molecular compounds in the precipitation bath and the plasticizing bath.-- Identification of the PB composition. It has been shown that the low-molecular compounds evolved into the PB are not linear oligomers but polymetaphenylene isophthalamide, and presumptively, they have a cyclic structure.-- The effect of contaminants in isophthaloyl chloride and in dimethylacetamide on the quantitative and qualitative composition of the PB and P/B has been studied.-- It has been established that the main contaminants which affect the composition of PB are isophthalic and acetic acids.Translated from Khimicheskie Volokna, No. 5, pp. 35–37, September–October, 1991.