Action of a dc electric current on viscose

Conclusions Under the action of a dc electric current having a voltage of 10–50 V on viscose under steady conditions, heating and electrolysis of the viscose take place; the temperature is increased nonuniformly throughout the volume of the cell: the preheating takes place more intensively in the anode compartment.The ripeness of the viscose and the degree of esterification of the cellulose xanthate are considerably reduced, and the gel-particle content decreases slightly; decomposition of the cellulose xanthate takes place via a dixanthogenide to the thioanhydride and low-molecular sulfur-containing products.Translated from Khimicheskie Volokna, No. 1, pp. 27–28, January–February, 1990.     

Effect of carbon disulfide consumption on the basic properties of viscose prepared from radiation-modified cellulose

Conclusions -- The process of preparing viscose from radiation-modified cellulose using carbon disulfide in the range of 6–32% of the weight of -cellulose in the xanthation has been investigated.-- Equations have been given which describe the dependence of the degree of esterification of the cellulose xanthate, the ripeness index, the byproduct content, the viscosity, and the filterability of the viscoses on CS₂ consumption in xanthation within the range 6–32% by wt.-- It has been found that a decrease in consumption of CS₂ primarily affects the viscosity of the viscoses obtained, and then it affects figures which characterize the content of byproducts, degree of esterification of the cellulose xanthate, ripeness, and the filterability of the spinning solutions.Translated from Khimicheskie Volokna, No. 5, pp. 51–53, September–October, 1991.     

Formation of secondary gel particles in viscose

Conclusions -- It has been shown that the content of secondary gel particles in viscose rises significantly with temperature increase.-- The formation of secondary gel particles takes place because of decomposition of the cellulose xanthate in an immobile wall layer of the viscose.Translated from Khimicheskie Volokna, No. 4, pp. 35–36, July–August, 1990.     

Kinetics of the decomposition of cellulose xanthate in alkaline medium at elevated temperatures

Conclusions The kinetics of decomposition of cellulose xanthate in alkaline medium at temperatures of 70–180°C under laboratory conditions has been described. Viscoses with an alpha cellulose content of 6.9±0.12% and an alkali content of 3.97–9.95% by wt. were used as the investigated solutions.It has been shown that the rate of splitting off thiocarbonate groups from the second and third carbon atoms in the cellulose xanthate molecule is greater than the rate of splitting off thiocarbonate groups from the sixth carbon atom. The rate constants of these reactions and their activation energies have been calculated.Translated from Khimicheskie Volokna, No. 6, pp. 21–22, November–December, 1983.     

Change in polydispersity of degree of esterification of cellulose xanthate during the process of viscose ripening

Conclusions A method of determining the polydispersity of the degree of esterification () of the cellulose xanthate in viscose has been proposed, plus an algorithm for calculating it.The change in density of distribution of in cellulose xanthate during viscose ripening over a period of 96 h at 16°C has been studied.It has been found that the dispersion in density of distribution of in cellulose xanthate continuously decreases during ripening.Translated from Khimicheskie Volokna, No. 1, pp. 18–21, January–February, 1989.     

Spinning hydrocellulose fibres into zinc-free precipitation baths

Conclusions -- It has been found that the introduction of sodium vinyl sulfonate into the solvent alkali does not exert any important effect on the properties of the viscose, with the exception of stabilizing the cellulose xanthate and retarding its coagulation under the conditions of viscose ripening.-- Sodium vinyl sulfonate added to the dissolving alkali reacts with groups in the cellulose xanthate and to a very slight degree with hydroxyl groups in the cellulose.-- Fibres have been spun from the viscose containing sodium vinyl sulfonate, in the preparation of which it was possible to carry out a higher orientation stretch and to attain better physico-mechanical indices as compared with fibres from viscose containing no sodium vinyl sulfonate.Translated from Khimicheskie Volokna, No. 1, pp. 38–40, January–February, 1991.     

The preparation and properties of cellulose/chitin blend filaments

The focus of this article is the preparation and characterization of cellulose/chitin blend filaments obtained from cellulose/chitin xanthate blend solution over the experimental blend ratio, i.e., 2.89% and 6.46% (w/w) chitin content. The addition of chitin xanthate into cellulose xanthate leads to an increase of intermittence rate and the blend solution has good filtering property. Scanning electronic microscope photos shows that there exist grooves on the filaments surface, which are becoming coarse with increasing chitin content. The mechanical properties of the spun blend filaments is much higher than that of Crabyon® fiber, which proves that the viscose method we adopt here is an efficient way to prepare cellulose/chitin blend filaments with satisfactory mechanical properties and processing property. Based on the data from X‐ray, sonic velocity, equilibrium regain rate, and accessibility, it is concluded that the degree of crystallinity, modulus, degree of orientation, density, equilibrium regain rate, and accessibility of blend filaments decreases with increasing chitin content in the blend filaments in the experiment scope. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Solution of cellulose xanthate at elevated alkali contents

Conclusions A method has been developed for dissolving cellulose xanthate at a higher NaOH content in the first period of solution. The optimum NaOH content for this purpose is 9–9.6%.All-Union Synthetic Fibre Research Institute (VNIIV). Translated from Khimicheskie Volokna, No.2, pp. 60–61, March–April, 1969.     

Evolution of carbon disulfide and hydrogen sulfide in spinning viscose fibres

Conclusions It has been found that the rate of decomposition of the byproducts and of cellulose xanthate differ considerably from the rate of evolution of the gases formed.Carbon disulfide in the chemically unbounded state forms stable emulsions with the components of the precipitation bath.The kinetics of carbon disulfide evolution in the plasticizing treatment of viscose fibre is described by a zero order reaction equation.Translated from Khimicheskie Volokna, No. 6, pp. 44–45, November–December, 1985.     

蔗渣浆制造黏液纤维的研究

<正>在黏液纤维制造中,用蔗渣浆代替木浆作原料,常被人怀疑甚至否定其可能性,其主要根据为草类纤维的形态结构不同於木材纤维,而以天然纤维的形态结构作为对原料适合与否的判断标准。我们认为:黏液丝浆的良好制备条件均应最大限度地破坏了天然纤维的形态结构,主要是细胞壁的组织。後者的存在影响丝光化与黄酸化的反应     

Effect of polyvalent metal ions on the rate of decomposition of cellulose xanthate in the precipitation bath

Conclusions The use of aluminum salts instead of zinc salts considerably reduces the rate of decomposition of cellulose xanthate.This offers an opportunity to improve the stretching conditions of the freshly spun fibre.Translated from Khimicheskie Volokna, No. 3, p. 39, May–June, 1983.     

Solubility of sodium cellulose xanthate in aprotic solvents

Conclusions The solubility of sodium cellulose xanthate of various degrees of substitution in dipolar aprotic solvents has been examined.It has been shown that a xanthate with a low degree of substitution is soluble only in dimethyl sulfoxide, while a highly substituted one dissolves also in dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.A water content in the aprotic solvent improves the solubility of the cellulose xanthate, but a sharp decrease in the degree of polymerization and degree of substitution also takes place.Translated from Khimicheskie Volokna, No. 1, p. 27, January–February, 1984.     

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.     

Formation and decomposition of zinc cellulose xanthate in acid media

Complex formation between zinc (5 × 10^?2?5 × 10^?4M) and cellulose xanthate and its effect upon the rate of dexanthation by 0.25M sulfuric acid were studied. The determinations were based on spectrophotometric measurements on dilute solutions of cellulose xanthate with γ-numbers from 140 to 30. The results showed that the tendency of the xanthate groups to enter into complexes with zinc increased as the γ-number decreased. The stabilization toward decomposition by acid produced by complex formation was also found to vary with the γ-number and was much smaller at low than at high γ-numbers. These findings indicate that cellulose xanthate, because of local differences in the steric arrangement of potential ligand groups along the molecule, can form a whole set of zinc complexes, differing in thermodynamic stability and reactivity toward acid.     

Properties of cellulose xanthate solutions which have been subjected to action of γ-radiation

Conclusions In the action of -radiation on solutions of cellulose xanthate, the molecular weight nonuniformity of the polymer in solution is reduced, which is one of the reasons for the anomalous decrease in dynamic viscosity of the solution.The irradiated solutions of cellulose xanthate are characterized by increased homogeneity and stability with time as compared with unirradiated solutions.The considerable decrease in viscosity of cellulose xanthate solutions and the increase in its homogeneity under the action of high energy ionizing radiation present practical interest, since these make it possible to obtain solutions of cellulose xanthate with a comparatively low viscosity at high values of mean degree of polymerization and of polymer content of the solution.Transition of part of the -fractions (DP 50) into -cellulose (DP150 and 200) has been detected, which may be a consequence of radiochemical polymerization (cross-linking) in a solution of -cellulose or -cellulose and -cellulose.Translated from Khimicheskie Volokna, No. 5, pp. 24–26, September–October, 1989.     

Acid decomposition of highly substituted cellulose xanthate

The acid decomposition of cellulose xanthate was studied spectrophotometrically with a stopped-flow technique. The reactivity of the xanthate groups was found to decrease with an increase in the viscose γ number. This was explained by the occurrence of stabilizing interactions exerted between closely spaced xanthate groups. With uniformly substituted xanthates this effect began to be noticeable at γ numbers above 50. At higher γ numbers partial decomposition by acid resulted in an uneven distribution of xanthate groups along the chain molecules. Another feature of cellulose xanthate is that the degree of dissociation at constant acid concentration decreases with an increase in the γ number. This can be ascribed to variations in the dielectric constant inside the macromolecules.     

Reaction of cellulose xanthate with chromium compounds by UV spectroscopy

Conclusions The type of chemical bond in the chromium compounds obtained which are based on cellulose xanthate has been ascertained.It has been shown that, as a result of an oxidation-reduction reaction between the thiocarbonate groups of the cellulose xanthate and K₂Cr₂O₇ (in acid medium), a chromium xanthate is formed which has a covalent type of bond between the sulfur atoms and chromium.Translated from Khimicheskie Volokna, No. 6, pp. 29–30, November–December, 1987.     

Analysis of the causes of spinneret failure

Conclusions 1. The authors have studied the product of the reaction of formaldehyde with cellulose xanthate under the conditions of polynosic fibre forming plants.2. It is shown that during this reaction formaldehyde is added on to all the thiocarboxylic groups in the fibre.3. It has been established that during the reaction of formaldehyde with the decomposition products of viscose in the coagulation bath, mainly sulphonated analogues of polyhydroxymethylene glycols are formed.All-Union Scientific-Research Institute for Man-Made Fibres (VNIIV). Translated from Khimicheskie Volokna, No. 6, pp. 26–27, November–December, 1969.     

Some special features in the precipitation of hydrocellulose from cuprammonium solutions

Conclusions The effect of precipitation baths with varying precipitation power on the composition and swelling of gels precipitated from a cuprammonium cellulose solution has been examined.The degree of decomposition of the cellulose cuprammonium complex in aqueous-organic systems depends but little on the nature of the organic compound, but the degree of swelling of the freshly spun gel in aqueous-organic systems decreases with increase in the proportion of the organic component in the precipitation bath.Translated from Khimicheskie Volokna, No. 3, pp. 37–39, May–June, 1983.     

Comparison of ordinary and high-temperature mercerization of cellulose

The effect of an increase in the temperature of mercerization of cellulose on the average degree of polymerization of alkaline cellulose, viscosity, and filterability of viscose was investigated. In comparison to mercerization at 20°C, high-temperature mercerization accelerates decomposition of the cellulose and removes low-molecular-weight fractions from it and reduces the duration of production of alkaline cellulose with acceptable technological properties to 10 min.Advanced Institute of Chemical Technology, Bulgaria. Translated from Khimicheskie Volokna, No. 4, pp. 30–31, July–August, 1992.