Properties of polyacrylonitrile yarns which have been modified with salts of alkali metals

Conclusions In modification of polyacrylonitrile fibres with alkali metal salts, a change in structure takes place, morphological nonuniformity in the transverse direction is increased, which aids in fibre crimpingAlkali metal salts interact with Nitron fibre both at the carboxyl groups of the polymer and also at its carbonyl groups.Translated from Khimicheskie Volokna, No. 3, pp. 34–35, May–June, 1988.     

Thermogravimetric studies of polycaproamide fibre modified by grafting of polyacrylonitrile

The characteristics of thermolysis of graft copolymers of polycaproamide and polyacrylonitrile of fibrous structure were investigated. The effect of the products of thermal oxidation of the graft copolymer on cross-linking of its thermoplastic polycaproamide component was demonstrated. It was found that the thermochemical transformations of the graft copolymer of polycaproamide and polyacrylonitrile in conditions of thermal oxidation cause formation of a structure of the polymer that ensures a high yield of carbonized residue in a wide range of temperatures.     

Supermolecular structure of diacetate fibres which have been modified with polytetrafluoroethylene

Conclusions It has been found that the degree and character of structural transformations of acetate fibre in the process of graft polymerization of PTFE depend on the content of grafted-on polymer.The grafted-on polymer is localized both on the surface and also in free spaces inside the fibre.Translated from Khimicheskie Volokna, No. 3, pp. 27–29, May–June, 1988.     

Some properties of modified polyacrylonitrile fibres

Fibre-forming copolymers of acrylonitrile and a monomeric quaternary ammonium salt, β-methacryloylhydroxyethyl-(N-dimethyl,methylene)ammonium iodide, were obtained by wet spinning and their physicomechanical and structural properties were investigated. It was found that the modified fibres have a set of valuable properties in comparison to the industrial fibre Nitron.     

Deformation properties of modified polyacrylonitrile fibres

Conclusions Deformation properties of polyacrylonitrile fibres modified with alkali metal salts have been studied.The introduction of alkali metals by treatment of freshly spun gel-fibre with solutions of the appropriate salts aids in loosening fibre structure.Both the form of cation and also of the anion in the salt introduced affect the deformability of the modified fibres.Translated from Khimicheskie Volokna, No. 4, pp. 40–41, July–August, 1989.     

Microscopic study of modified polyacrylonitrile fibres

Conclusions Microscopic studies have been made on polyacrylonitrile fibres which have been modified with solutions of CdSO₄, ethylenediamine, and a mixture of these solutions.Treatment with an ethylenediamine solution aids in a significant change in structure of the fibre surface.Treatment with a mixture of CdSO₄ and ethylenediamine solutions leads to development of a structural nonuniformity in the fibre and the twisting of the fibre on drying in the free state.Translated from Khimicheskie Volokna, No. 2, pp. 33–34, March–April, 1989.     

Properties of fibrous materials which have been treated in a gas discharge

Conclusions As a result of treatment of fibrous materials with a gas discharge plasma, their physicomechanical properties are changed.The weakening of intermolecular interactions which is observed after treatment in a gas discharge, and the increase in mobility aid interdiffusion of the polymer macromolecules upon contact and application of pressure, which leads to a strengthening in autohesive contact in polypropylene fibrous materials.The reasons which are responsible for the change in physico-chemical properties of materials that have been treated with a gas discharge have been investigated.Translated from Khimicheskie Volokna, No. 2, pp. 51–52, March–April, 1987.     

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.     

Preparation of fire-resistant polycaproamide fibres

Conclusions A method had been developed for the preparation of fire-resistant polycaproamide fibres; it uses a three-component synergistic system of combustion retarders: boric acid + brominated pentaerythritol + antimony oxide.The effect of the synergistic system of combustion retarders is supported by the value of the oxygen index for the fire-protected polycaproamide fibres and by data from differential thermogravimetric analysis.Translated from Khimicheskie Volokna, No. 1, pp. 51–52, January–February, 1988.     

Ion-exchange fibres based on polyacrylonitrile modified with heteroorganic compounds

Conclusions A method has been developed for the preparation of ion-exchange fibres based on polyacrylonitrile, using alkali metal alkylsiliconates as modifying agents.The role of the sodium alkylsiliconate in the process of modifying PAN fibres has been ascertained by physicochemical methods. It has been shown that silicon is introduced into the structure of the fibre as a result of the modification.The possibility of using tetraethoxysilane as a cross-linking agent for PAN fibres has been investigated.Leningrad Institute of Textile and Light Industry. Translated from Khimicheskie Volokna, No. 1, pp. 16–19, January–February, 1987.     

Structure of twisted polyacrylonitrile fibres modified with cadmium sulfate and ethylenediamine

Conclusions Treatment of freshly spun polyacrylonitrile gel-fibre with CdSO₄ solution leads to an increase in its thermal stability.Treatment with a mixture of CdSO₄ and ethylenediamine solutions causes the development of structure nonuniformity and twisting of the fibre.Translated from Khimicheskie Volokna, No. 2, pp. 34–36, March–April, 1989.