Effect of sodium triphosphate on thermal decomposition of hydrated cellulose fibres

Incorporation of sodium triphosphate to hydrated cellulose fibre decreases the temperature at which intense degradation of hydrated cellulose begins. Primarily localized in not very ordered areas of HC, sodium triphosphate decreases the intensity of their thermal decomposition, and the processes related to intense degradation probably take place as in the more ordered (crystalline) areas. Sodium triphosphate is present in the carbonized residue (heat treatment temperature of 900‡C) in the form of NaPO ₃ (metaphosphate) and Na₄P₂O₇ (pyrophosphate). The CF obtained in carbonization are promising as raw material for fabrication of sorption-active CFM. Translated from Khimicheskie Volokna, No. 1, pp. 27–30, January–February, 1997.     

Thermal behavior of bicomponent systems of polyacrylonitrile and hydrated cellulose fibres

Mixed bicomponent systems of polyacrylonitrile (PAN) and hydrated cellulose (HC) fibres are not mechanical mixtures with the additive properties of each component; their thermooxidative degradation takes place at lower temperatures than for each fibre individually, and takes place less actively and in a wider range of temperatures. When the degree of grinding of the fibres in the mixed systems is decreased, the temperature of the beginning and rate of thermooxidative degradation also increase. Increasing the concentration of HC fibre in the mixture from 15 to 50 wt. % decreases the heat effect of the first exothermic peak on the DTA curve, and this is of practical importance for conducting heat treatment of the fibres.All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna, No. 6, pp. 27–29, November–December, 1992.     

Analysis of the evolution of production of hydrated cellulose textile fibres

In summing up the observations given below on the future of new cellulose fibres, including comparing them with natural fibres (cotton), some generalizations can be made: The constant increase in the demand for cellulose-based textile fibres is not only due to the tendency toward a higher standard for clothing and satisfaction of the needs of the growing population, but also to the specific features of the properties of cellulose fibres (natural and man-made), especially hygroscopicity and hygiene: in this respect, the new fibres for linen clothing are significantly better than synthetic fibres, second to the latter only in fabrics for water-repelllent clothing; an analysis of the possibilities of solving the problem of the increasing demand for cellulose fibres by expanding production of cotton and increasing production of man-made cellulose fibres leads to the following conclusions: the increase in areas planted with cotton could be slowed by an increase in the demand for fields for grains and the limited possibilities of restoring previous catastrophically destroyed sources of irrigation water; while preserving or expanding production of cotton, primarily by increasing productivity, it is necessary to significantly increase production of man-made fibres; for this reason, the main restriction which had previously not permitted adding new HC fibre enterprises primarily produced by the viscose process, which does not meet current ecological requirements, has been removed; for this reason, the advances in spinning of cellulose fibres from solutions in direct solvents (primarily MMO) make this method fundamental in solving the problem of satisfying the demand for cellulose fibres; in using the new method of manufacturing HC fibres, one of the serious conditions for increasing total production of chemical fibres should also be considered; this does not eliminate the need for progress in the synthetic fibre field, although with respect to some physical, particularly strength, properties, MMO fibres can partially take on the function of textile materials which synthetic, basically polyester, fibres currently fulfill; some properties of the new fibres, in particular, their capacity for surface fibrilation, require improvement, but although this is difficult, it is nevertheless a totally solvable problem. The questions discussed in the present article require further elaboration and more precise definition, but they undoubtedly constitute an important part of the overall prognosis for production and correspondingly scientific studies of fibres.Translated from Khimicheskie Volokna, No. 3, pp 17–19, May–June. 1996.     

Use of liquid ammonia to increase the quality of textiles made of hydrated cellulose fibres

A method was developed for preparation of samples for determining the adhesive strength of joints of thermoplastics with CF 6–9 µm in diameter by the pull-out method. The proposed method can be used to evaluate the adhesive power of thermostable thermoplastics (polyphenylene sulfide, polycarbonate, polysulfone, polyphenylene sulfide sulfone). The strength of the interface in bonds of these polymers with UKN-5000 fibres in the selected spinning conditions is sufficiently high and is as good as the adhesive strength of bonds of fibres with modified epoxy resins.Institute of Chemical Physics, Russian Academy of Sciences, Moscow; Tekhnologiya ONPP RF GNTs, Obninsk. Translated from Khimicheskie Volokna, No. 4, pp. 33–37, July–August, 1995.     

Thermal transformations of polyvinyl alcohol and hydrated cellulose fibres in the presence of phosphates of nitrogen-containing organic compounds

Effective new pyrolytic additives 5-methyl-2-ethyl-3-hydroxypyridine and polyhexamethyleneguanidine phosphates, which ensure a high yield of carbon fibre (31–34%) from hydroxyl-containing polymeric precursors, are proposed as a result of the studies. The high activity of these activated carbon-fibre materials in sorption of acetone was demonstrated. __________ Translated from Khimicheskie Volokna, No. 3, pp. 3–6, May–June, 2007.     

Properties of fibres of cellulose acetomethacrylates

Conclusions 1. The authors have shown that fibres can be formed for acetic acid syrups of mixed esters of cellulose with acetic and methacrylic acids.2. The effect of the composition of cellulose acetomethacrylate on the physicomechanical properties and degree of orientation of the fibres has been studied. It has been established that maximal improvement of the strength and degree of orientation of the fibres takes place at _max=7–9.3. The change in fibre structure in relation to the methacrylic acid content has been studied by electron-microscopic analysis. It is shown that the structural uniformity of cellulose acetomethacrylate fibres improves at _max=7–9; a further increase in _max leads to a decrease of the structural uniformity.First communication of a series devoted to Preparation of fibres on the basis of cellulose esters, and study of their properties.NIIKhTTs. Translated from Khimicheskie Volokna, No. 5, pp. 41–43, September–October, 1969.     

Fabrication of chemisorption amino-containing cellulose fibres

These studies revealed the effect of the polymer matrix on graft polymerization of glycidyl methacrylate. The high efficiency of the Cu_c–H₂O₂ redox system (RDS) in graft polymerization of glycidyl methacrylate (GM) to hydrated cellulose (HC) fibre was demonstrated. Amino-containing HC chemisorption fibres with a SEC of 2.9 meq/g were fabricated.Moscow State Textile Academy. Translated from Khimicheskie Volokna, No. 5, pp. 46–49, September–October, 1996.     

Destruction of cellulose during the process of sintering fibres from dispersions of polytetrafluoroethylene

Conclusions On heat-treatment of unsintered PTFE fibres, initially a thermo-oxidative destruction takes place, and then a pyrolysis of the matrix polymer (cellulose), with simultaneous sintering of the Teflon particles.The end of PTFE sintering coincides in time with the end of the cellulose degradation process. A carbonized residue, in the amount of 1.5–2.5% of the fibre weight, remains in the yarn.Translated from Khimicheskie Volokna, No. 3, pp. 33–34, May–June, 1983.     

Heat treatment of high-molecular-weight cellulose acetate fibres

The conditions for heat treatment of high-molecular-weight cellulose acetate fibres which ensure formation of an ordered fibre structure with elevated strength properties were established. An ordered structure can be obtained in heat treatment if the acetate fibre is wet spun with positive spinneret drawing.Scientific-Research Institute of Chemistry, Saratov State University. All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna, No. 6, pp. 29–31, November–December, 1992.     

Double drying of polyacrylonitrile fibres for technical purposes

Conclusions -- The kinetics of double drying of polyacrylonitrile tow has been studied.-- An empirical equation has been obtained for determining the drying time as a function of the temperature of the heating surface.Translated from Khimicheskie Volokna, No. 3, pp. 58–59, May–June, 1991.     

Regenerated cellulose fibres after controlled enzymatic hydrolysis

Controlled enzymatic hydrolysis of cuprammonium and various types of viscoses was undertaken to gain some insight into the heterogenity of the structure from the surface to core. Electron microscopic study of the hydrolysed samples at various stages of hydrolysis, also gives general idea of the morphological differences in these regenerated celluloses. The difference in the physical and especially the mechanical properties of the different types of these fibres can now be more definitely correlated with their structure.     

Sorption studies of hydrated cellulose fibre having a liquid-crystal structure

The liquid-crystal structure of hydrated cellulose fibre fabricated in conditions of decomposition of copper—ammonia cellulose complex in anhydrous medium was sufficiently resistant to water vapors, in particular, in conducting sorption measurements for many days. The curve of the diffusion coefficient as a function of sorption of water vapors was extreme.All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna, No. 3, pp. 26–29, May–June, 1994.