Properties of viscose prepared from modified cellulose

Conclusions Some basic characteristics of viscose prepared from radiation-modified cellulose as compared with standard viscose have been determined.It has been shown that viscose from RMC has an increased coagulation resistance and increased physicochemical uniformity as compared with standard viscose of analogous composition.Translated from Khimicheskie Volokna, No. 2, pp. 32–34, March–April, 1990.     

Preparation of integrally spun viscose sausage casings using radiation-modified cellulose

Conclusions The effect of precipitation bath parameters on the physicomechanical properties of integrally spun sausage casings prepared using radiation-modified cellulose has been studied.It has been found that the use of radiation-modified cellulose ensures the possibility of producing a high-quality product with a reduction of the consumption of carbon disulfide in xanthation to 10–15% based on wt. of -cellulose.Ukrainian NIIV (Kiev). Translated from Khimicheskie Volokna, No. 3, pp. 47–49, May–June, 1993.     

Sorption and desorption of carbon disulfide by cellulose for viscose manufacture

Conclusions -- The results of a study of the sorption and desorption of carbon disulfide may be used to characterize the structure of cellulose, particularly its accessibility to reagents during viscose manufacture.-- After high-temperature mercerization, the accessibility of cellulose with respect to carbon disulfide is increased.-- The reverse method of viscose preparation makes it possible to intensify the penetration of carbon disulfide into the cellulose fibres to a considerable extent, particularly into the most inaccessible portions of its structure.Higher Chemical Engineering Institute, Bulgaria. Translated from Khimicheskie Volokna, No. 3, pp. 17–19, May–June, 1992.     

Self-ignition of activated carbons in the recovery of carbon disulfide from exhaust air from viscose manufacturing

Conclusions Reasons for the self-ignition of activated carbons have been ascertained, based on an analysis of the mineral portion of such carbons.It has been found that the self-ignition temperature of industrial types of activated carbon depends on their alkali metal content.It has been shown that heating up of granules of activated carbon takes place as a result of an exothermic oxidation of carbon to carbon dioxide.Cases of self-ignition of activated carbons in the recovery of carbon disulfide from exhaust air from viscose plants are explained by an impregnation of individual, usually overdried, dusty regions with alkali metal salts.Translated from Khimicheskie Volokna, No. 6, pp. 11–12, November–December, 1984.     

Clean-up of low-concentration ventilation discharge from viscose manufacturing plants from carbon disulfide and hydrogen sulfide

Conclusions An analysis has been made of existing methods of cleaning up low-concentration gas discharges from viscose manufacturing from hydrogen sulfide and carbon disulfide.It has been found that the most effective method of purification in that which uses ion-exchange and carbon materials, and which requires developing apparatus (filters) of large unit capacity.For a number of plants, it is recommended to use the the thermal method of cleaning up low-concentration discharges from hydrogen sulfide and carbon disulfide; this is characterized by simplicity and low economic costs.A radical solution to the problem of protecting the air reservoir from contaminants is the development of low-waste technology including utilization of gaseous discharges. Low-waste technology in the manufacture of viscose fibre is being developed in the Khimvolokno NPO and will be realized in the very near future in one of the sub-branch plants.Translated from Khimicheskie Volokna, No. 6, pp. 6–9, November–December, 1984.     

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.     

Effect of xylan on viscose properties

Conclusions The effect of xylan on viscose quality has been studied.An adverse effect of both alkali-soluble and alkali-insoluble xylan fractions on viscose quality (turbidity, CS₂ distribution) has been found. This forms a basis for requirements on pentosan content of celluloses.It is suggested that evaluation of viscose fromleafy wood cellulose use the turbidity character istic.Translated from Khimicheskie Volokna, No. 1, pp. 43–44, January–February, 1987.     

Effect of urea on the properties of viscose

Conclusions Additions of urea to viscose lead to a small increase in density and ripeness index, and to a decrease in its viscosity.Urea in viscose does not enter into specific interactions with the components of the viscose and is not decomposed.The change in properties of viscose on increasing the urea content is explained principally by an effect of dilution of the polymer solution.The authors express their thanks to V. G. Kulichikhin for help in this work and for participation in discussing the results.Translated from Khimicheski Volokna, No. 1, pp. 24–26, January–February, 1986.     

Effect of surface-active substances and of carbon disulfide in the viscose manufacturing precipitation bath on the chemical resistance of rubber materials

Conclusions As a result of this study, it has been found that the effect of surface-active substances, solutions of sulfuric acid, or of a model precipitation bath on the chemical resistance of rubbers is slight.The carbon disulfide contained in a real precipitation bath exerts the greatest effect; this causes swelling of the material and a significant loss in strength and elongation.These results must be taken into account in selecting materials for rubberizing reservoirs in chemical manufacturing operations.Translated from Khimicheskie Volokna, No. 6, pp. 32–33, November–December, 1985.     

Sorptive properties of fibres prepared from cuprimonium solutions of cellulose

Conclusions -- The sorption of water vapor by copper-containing and by final hydrocellulose fibres from the cuprimonium preparation method essentially does not depend on the concentration of the water-diethylene glycol precipitation bath or on stretching in the range up to 34%, which indicates formation of structures which are close to amorphous fibre in packing density under these conditions.-- The specific surface of both copper-containing and also of hydrocellulose fibres which have been dried by solvent replacement depends on the composition of the water-diethylene glycol bath, wherein this dependence has a bimodal character.VNIIPV, Mytishchi. Translated from Khimicheskie Volokna, No. 3, pp. 25–26, May–June, 1992.     

Acceleration of graphitization on carbon nanofibers prepared from bacteria cellulose dispersed in ethanol

Bacteria cellulose is composed of pure cellulose nanofibrils with about 30–60 nm width. The original conglomerate of bacteria cellulose was dispersed in ethanol or distilled water and filtered, and paper like sheets were prepared. The conglomerate itself and the sheets were carbonized and then heat-treated at 3100 °C. The development of graphite structure by the heat treatment was observed for these sheets, especially for that derived from the nanofibrils dispersed in ethanol, while the heat-treated conglomerate exhibited the nature of nongraphitizing carbon. The difference in graphitizability seems to be attributed to graphitization behavior on the surface of nongraphitizing carbon.