Changes in the structural-mechanical properties of nitron fibre during the metallizing process

Conclusions The effect of metallizing conditions and Ni content on the structural and mechanical properties of Nitron fibre has been investigated.It has been shown that the metallization temperature-time regime leads to changes both in the amorphous and also in the crystalline regions of PAN fibre; these are connected with a compaction in polymer structure.The Ni content of the fibre significantly affects its structure and thermomechanical properties. The suggestion has been made that the considerable increase in glass point of the fibre is caused by chemical interaction between polymer functional groups and the metal.Translated from Khimicheskie Volokna, No. 6, pp. 39–40, November–December, 1986.     

Chemical changes in polyvinyl fluoride during the process of fibre-spinning

Conclusions The change in some properties of polyvinyl fluoride during the process of fibre spinning has been investigated.It has been found that during the process of converting PVF powder into fibre, the degree of polymer crystallinity plus its resistance to thermal and thermooxidative degradation is increased; depending on the spinning regime, the densities and physicomechanical properties of PVF fibres are different.Translated from Khimicheskie Volokna, No. 4, pp. 34–35, July–August, 1984.     

Effect of finishing on chemical and structural changes in viscose fibres

Conclusions -- Comparative studies have been carried out of the change in properties of ordinary viscose fibre and high-modulus viscose fibre during the finishing process.-- It has been shown that oxidative degradation and hydrolysis take place more intensively during final regeneration and alkali desulfuration and to a larger degree this is characteristic of ordinary viscose fibre; thereupon, additional crystallization of the cellulose takes place.Translated from Khimicheskie Volokna, No. 5, pp. 40–42, September–October, 1991.     

Fibres from a mixture of xylylene diamides obtained from a natural mixture of xylenes

Conclusions 1. A process has been developed for obtaining polymer and fibre of Xylon MP, based on the natural m-xylene fraction.2. A comparative study has been made of the properties of Xylon MP and Xylon M fibres.3. It has been shown that the heat resistance and thermal stability of fibre obtained from Xylon MP are superior to those of Xylon M fibre.All-Union Scientific-Research Institute for Man-Made Fibre (VNIIV). Translated from Khimicheskie Volokna, No. 6, pp. 59–61, November–December, 1969.     

Reaction of nitron fibre with nickel during the chemical metallization process

Conclusions The structure and properties of metallized Nitron fibre have been studied by the methods of measuring electrical conductivity, polymer extraction, sorption of water vapor, IR spectroscopy, and thermomechanical investigation.It has been shown that metallization causes a significant change in the electrophysical, sorptive, and thermomechanical properties of Nitron fibre.The suggestion has been made that the change in the set of properties of Nitron fibre upon metallization is caused by interactions of various types between the polymer and the metal.Translated from Khimicheskie Volokna, No. 5, pp. 24–26, September–October, 1987.     

Research on fabrication of carbon fibre sorbents based on cellulose acetates

The basic characteristics of thermal transformations of fibres obtained as a result of alkaline hydrolysis of cellulose acetates in the stage of oxidation and carbonization were investigated. A correlation was established between the composition, structure, and properties of the starting polymeric raw material and the carbonized materials. The expediency of conducting hydrolysis of the ester bond of cellulose acetates, which results in splitting of acetyl groups in the low-temperature region, was substantiated. The important possibility of obtaining carbon fibre sorption materials based on acetate fibres was demonstrated.Translated from Khimicheskie Volokna, No. 5, pp. 44–48, September–October, 1995.     

Effect of aerodynamic spinning parameters and polymer properties on fibre diameter

Conclusions On the basis of theoretical calculations by a mathematical model of the process of aerodynamic spinning of polymer melts, whose adequacy has been established from experimental data, the sensitivity of final fibre diameters to change in technological spinning parameters and on the thermophysical and rheological properties of the polymer has been determined.It has been shown that among the factors which most significantly affect the final fibre diameter are the velocity of air movement in the ejector, the polymer flow rate, the temperature of the melt, the density of the melt, the viscosity anomaly, and the activation energy of viscous flow.Translated from Khimicheskie Volokna, No. 5, pp. 37–39, September–October, 1988.     

Modification of polyacrylonitrile fibre with hydrolyzed wastes

Conclusions Principles governing the alkaline hydrolysis of wet Nitron fibre waste and their solubilities in 51.5% aqueous sodium thiocyanate solution have been studied. It has been found that the best solubility is attained at an SEC of 0.17–0.20 meq/g. The solutions obtained on addition of these wastes are characterized by reduced viscosity, better filterability, and a reduced gel-particle content.It has been found that stable spinning and preparation of fibre with better physicomechanical characteristics are achieved when 5% by wt. of the hydrolyzed products is added to the spinning solution.Translated from Khimicheskie Volokna, No. 1, pp. 10–11, January–February, 1989.     

Preparation of fibres modified with enzymes having milk-curdling activity and their properties

Conclusions Conditions have been found for preparing enzyme-containing fibres with milk-coagulating activity.The effect of the type of carrier fibre, the character and content of functional groups, the disposition of these with respect to the main polymer chain, and also of the enzyme concentration on the milk-coagulating activity of enzyme-containing fibres has been established.A high stability of enzymes immobilized on fibres has been shown, plus the possibility of repeated use of enzyme-containing fibres for the preparation of milk curd.Leningrad Institute of Textile and Light Industry. Translated from Khimicheskie Volokna, No. 2, pp. 11–14, March–April, 1987.     

Kinetic relationships in acylation of thermal amino groups in reaction solutions of poly-m-phenyleneisophthalamide

Conclusions The kinetics of acylation of amino groups in acid reaction solutions of poly-m-phenylene-isophthalamide oligomers (or polymer) has been examined. The course of the process is described by zero order with respect to amino group concentration. The rate of acylation is determined by the acylating properties of the dimethylacetamide-hydrogen chloride system.Similar kinetic relationships were found for m-phenylenediamine. The reactivity of the terminal amino groups hardly changes on transition from m-phenylenediamine to PMPI oligomer (polymer), apparently due to the fact that the course of the process is limited by the properties of the acylating system.It has been shown that reduction in acidity or in medium temperature reduces the contribution of this reaction to termination of the PMPI polymer chain and correspondingly raises the quality of the reaction solutions.Translated from Khimicheskie Volokna, No. 6, pp. 15–17, November–December, 1989.     

Change in molecular weight characteristics of an aromatic copolyamide during the polycondensation process

Conclusions The change in molecular weight characteristics and in viscosimetric data during the synthesis process of an aromatic copolyamide has been analyzed. It has been found that, with rise in the degree of completion of the reaction, at definite molecular weight values the dynamic viscosity rises sharply, which indicates the presence of a significant structural component of this system.The effect of polymer molecular weight on fibre physicomechanical properties has been shown. An increase in fibre strength has been noted on increase in molecular weight from 5400 to 7300. The impairment in physicomechanical properties on further increase in polymer molecular weight is connected with difficulties in processing the strongly structured spinning solutions. Processing polymer with a high molecular weight, and, as a consequence, with an elevated dynamic viscosity requires new approaches both to spinning conditions and, possibly, also to synthesis conditions.Translated from Khimicheskie Volokna, No. 2, pp. 29–30, March–April, 1989.     

Sorption of transition metals by polyfunctional vion fibre sorbents

The selectivity and sorption capacity of polyfunctional fibre sorbents containing carboxyl, hydrazidine, and amidoxime groups are a function of the ratio of these groups in the polymer chain in absorption of transition metal ions from low-concentration solutions. The selectivity for nickel ions is determined by the ratio of carboxyl and hydrazidine groups, while the selectivity for copper ions increases significantly when 3–5 wt. % amidoxime groups are incorporated in the polymer chain in addition to the indicated units.All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna, No. 3, pp. 24–26, May–June, 1995.     

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 features of heterophase graft polymerization on synthetic fibers from thermoplastic polymers

Conclusions A considerable effect of structural-physical properties and molecular dynamics of the polymer as a solid on the process of radical graft polymerization to fibres from thermoplastic polymers which have been spun from the melt has been found.In the case of heterophase graft polymerization of vinyl monomers to polypropylene fibre, it has been shown that orderedness of the polymer structure primarily affects the initiation stage.High kinetic parameters of heterophase graft polymerization in oriented systems from thermoplastic polymers can be realized only at temperatures which exceed the glass point of the polymer matrix.Moscow Textile Institute. Translated from Khimicheskie Volokna, No. 1, pp. 7–9, January–February, 1987.     

Some features of fibre preparation from a copolymer of acrylonitrile with 5-vinyl-2-methylpyridine

Conclusions Increasing the content of ionogenic grups in a copolymer of acrylonitrile with 5-vinyl-2-methylpyridine leads to a change in intermolecular interaction is solutions of the polymer, and this exerts an effect on their rheological properties.The parameters of the process of spinning and fibre strengthening are determined by the composition of the copolymer, a change in fibre properties being observed at a content of active groups in the copolymer which is greater than 40% by wt.Translated from Khimicheskie Volokna, No. 3, pp. 17–19, May–June, 1986.     

Effect of aqueous treatment on the relaxation properties of fibres based on an aromatic polyamide

Conclusions The effect of water treatment on the relaxation properties of heat-treated fibre based on poly-p-phenylenebenzimidazole (PABI) has been studied by the dynamic mechanical loss method.It has been shown that water treatment leads to a disordering of the highly-oriented state of PABI fibre.The suggestion has been made that the amorphous polymer structure is heterogeneous.Translated from Khimicheskie Volokna, No. 2, pp. 33–34, March–April, 1988.     

Effect of metal salts on the dyeing of freshly spun polyacrylonitrile fibre with acid dyes

Conclusions The effect of the metal cations Al³⁺, Zn²⁺, and Cr³⁺ on the process of dyeing freshly spun PAN fibres with acid dyes has been studied. It has been found that the greatest amount of dye is fixed on the fibre when Al³⁺ ions are introduced into the dye bath.On the basis of analysis of the IR spectra of the dyed fibres, a mechanism has been proposed for the interaction of both the metal cations and also of the dye with PAN fibre. It has been found that the metal cation is bonded with the fibre both by an ionic bond with the—COOH groups and also by a coordination bond with >C=0 groups of the polymer substrate.Translated from Khimicheskie Volokna, No. 6, pp. 13–14, November–December, 1986.     

Copolymerization of acrylonitrile,methyl acrylate,and itaconic acid in thiocyanate solutions in the presence of hydrolyzed nitron fibre waste

Conclusions -- The kinetics of the copolymerization process of AN, MA, and IA in the presence of hydrolyzed Nitron fibre characterized by various degrees of hydrolysis has been studied. It has been found that introducing H-PAN into the reaction mixture leads to an increase in degree of conversion in the copolymerization process and to an increase in molecular weight of the copolymer synthesized.-- Fibre has been spun from the products of joint copolymerization of AN, MA, and IA in the presence of H-PAN with various concentrations of these in the solution and various SEC values. Introducing up to 5% by wt. of an H-PAN with an SEC not over 0.2 meq/g into the reaction mixture aids in obtaining fibres with satisfactory properties and opens up the possibility of still another way of solving the question of regenerating wet Nitron fibre wastes.Translated from Khimicheskie Volokna, No. 4, pp. 17–19, July–August, 1991.     

Operational properties of the chemisorptive fibre VION AN-1

Conclusions Boundary conditions have been determined for the regeneration of VION AN-1 fibre which ensure retention of its sorptive properties on repeated use.The rate of sorption of acid vapors depends on the original fibre structure only at a low relative humidity of the gas stream.On sorption of acid vapor by the moistened fibre, hydration of the ionogenic groups of the polymer takes place; this leads to a change in its structure. In this case, the rate of sorption does not depend on the porosity of the original fibre.Translated from Khimicheskie Volokna, No. 3, pp. 37–38, May–June, 1987.     

Effect of technological spinning transitions on the properties of nickel-containing nitron fibre

Conclusions The effect of technological spinning transitions on the properties of an electrically-conducting metallized Nitron fibre has been investigated.It has been shown that in mechanical crimping the mechanical and electrically-conducting properties of a nickel-containing fibre are considerably impaired. During the spinning process, a considerable leveling out of the nickel content of the fibre and of its electrical resistance takes place.Processing of the nickel-containing fibre should be carried out with elimination of the mechanical crimping process. Thereupon the change in fibre properties takes place mainly during the process of preparing the combed lap.Translated from Khimicheskie Volokna, No. 5, pp. 39–40, September–October, 1985.