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Sorption of chromium(VI) ions by fibre anion-exchangers containing pyridine, imidazole, hydrazidine, and aliphatic amino groups was investigated. It was shown that the basicity of the sorbents has almost no effect on their selectivity in absorption of chromium ions from solutions. The fibres with pyridine and imidazole groups have higher distribution coefficients, and their capacity for chromium ions is 130 and 120 mg/g, respectively. Sorption of chromium(VI) ions by the fibre sorbent with pyridine groups also corresponds to a mixed diffusion mechanism in dynamic conditions and the internal diffusion coefficient is 3.10−10 cm2/sec. Fibres with low-basicity pyridine groups are resistant to the oxidizing effect of chromium(VI) ions and their exchange capacity is preserved in repeated sorption-desorption cycles. Conversion of pyridine groups to the form of a strong base decreases the chemical stability of the sorbent in absorption of chromium(VI) ions from solutions.

When chemically active vinylimidazole is incorporated in the macromolecular polyacrylonitrile chain, an anomalous deviation of the viscosity from Newtonian flow is observed with an increase in the shear rate, caused by a change in the inter- and intramolecular interaction in the copolymer. Addition of up to 70 wt. % solvent in the plasticizing bath probably causes relaxation processes and the creation of a more compact structure, which allows for obtaining a fibre with satisfactory physicomechanical properties. Use of ED-20 epoxy—bisphenol A oligomer as the reagent for creating a three-dimensional chemical network in the copolymer is suggested.

The conditions were developed for synthesis of a copolymer of acrylonitrile and vinylimidazole in dimethyl sulfoxide capable of forming complexes with transition metals. Fabrication of a chemisorption fibre from AN-VIM copolymer was investigated. It was found that an increase in the concentration of VIM in the copolymer above 35 wt. % lowered the physicomechanical properties of the fibre. Incorporation of bulky VIM molecules which loosen the structure of the copolymer in the polyacrylonitrile chain affects the shrinkage characteristics of the fibre, manifested by a decrease in its service temperature to 50°C.

The relaxation properties of chemisorption fibers based on copolymers of acrylonitrile and 2-methyl-5-vinylpyridine synthesized in aqueous medium and in dimethyl sulfoxide were investigated. It was shown that the conditions of synthesis of the copolymers affect the relaxation properties of the fibers. It was hypothesized that the change in the relaxation properties is due to the composite composition of the copolymers, which is determined by the copolymerization constants.

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.

Conditions for the preparation of salt forms of a chemisorptive fibre based on a copolymer of acrylonitrile and 5-vinyl-2-methylpyridine have been worked out.

A scheme has been suggested for the catalytic effect of carboxyl groups on the conversion of -C≡N groups in acrylonitrile copolymers in modification with hydrazine hydrate.

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.

Coefficients of internal diffusion and of mass-transfer have been measured in the sorption of hydrogen chloride, nitrogen dioxide, and iodine by weakly basic and strongly basic chemisorptive fibres.

A fractionation of an acrylonitrile-2-methyl-5-vinylpyridine copolymer with respect to composition and molecular weight has been carried out by the fractional precipitation method. The distribution of the copolymer with respect to composition has a bimodal character, which may exert an effect on the properties of solutions and fibres.

The sorptive properties of VION fibre with carboxyl groups have been studied. It has been shown that at an SEC over 3.5 meq/g no corresponding increase in degree of absorption of ammonia by the fibrous sorbent takes place.

Boundary conditions have been determined for the regeneration of VION AN-1 fibre which ensure retention of its sorptive properties on repeated use.

The effect of the basicity of the chemically active groups in chemisorptive fibres on their sorptive properties with respect to hydrogen sulfide has been demonstrated. In the regeneration of fibrous sorbents with alkali solutions, it is advisable to use weakly basic fibrous sorbents for the absorption of hydrogen sulfide.

The process of alkaline hydrolysis of nitrile groups in hydrazided Nitron fibre has been studied. It has been shown that introduction of hydrazidine groups into the polymer chain catalyzes the alkaline hydrolysis process because of a change in the basicity of the polymer chain.

According to published research /1~2/, fibre spun from the co-polymer of vinylidene cyanide (VDC) with vinyl acetate (VA) possesses good elasticity, heat resistance and photostability so that its practical utilization is of interest. On the other hand, the mechanical strength of this fibre (not above 15 kgf/mm 2) is lower than that of fibre produced from other acrylic polymers, a fact which naturally limits its practical value. In this contribution the results are reported of an investigation of the causes of the low mechanic~l strength of this fibre and the possibility of increasing it is @xplored.