The effect of topochemistry on polymer-analog transformations of graft copolymers of polycaproamide, hydrated cellulose, and polyvinyl alcohol with polyglycidyl methacrylate under the effect of different amines was established. The amine-containing sorption-active fibres exhibit high activity with respect to heavy metals and platinum-group metals.Chemisorbents, in particular, sorption-active fibres, play an important role in solving environmental problems (treatment of gas--air emissions and wastewaters from industrial enterprises, separation and concentration of valuable metals) and problems in occupational safety (creation of devices for protecting the respiratory organs) [1][2][3]. These fibres are a promising alternative to granulated ion-exchange resins due to the developed specific surface.The Chemical Fibre Technology Department at Moscow State Textile University has developed a large group of sorption-active fibres of different composite and chellfical composition based on graft copolymers [4, 5] using ionogenic monomers and polymer-analog transformations of highly reactive o~-oxide groups of graft polyglycidyl methacrylate (PGM) in amination and sulfonation reactions (Scheme 1).An efficient graft polymerization process has not yet been developed due to the specific features of polymerization of ionized monomers. For this reason, the method based on graft polymerization of nonionogenic monomers and chemical transformations of the graft polymer is preferred in industry. The method of initiation utilizing the CUk--H202 redox system proposed for these purposes, which allows fixing the copper complex in the fibre and subsequently formation ofa macroradical, makes it possible to synthesize graft copolymers of the fibre-forming polymers listed above with PGMA with a degree of conversion of 95-97% and without formation of homopolymer; this makes this stage of production of chemisorption fibres highly efficient.In studying the characteristics of graft polymerization, a topochemical effect was found. According to electron microscopic data, the layer of graft polymer almost does not touch the central part ofpolycaproamide (PCA) fibre even for an almost 100% PGMA content in the fibre, while in grafting of GMA to hydrated cellulose (HC) fibre, the graft polymer is distributed over the entire section, as indicated by the absence of a cavity in the fibre after etching. This distribution of the graft polymer affects both the occurrence of the reactions of chemical transformations of PGMA and the sorption activity of the fibre chemisorbents obtained.We used a large group of nitrogen-and sulfur-containing compounds for incorporation of sorption-active groups. The systematic studies of the chemical transformations of graft PGMA in different polymer matrices and under the effect of a broad spectrum of nitrogen-and sulfur-containing compounds were directed toward revealing the characteristics of this process and formulating fundamental scientific premises which would allow more successfully solving practical problems in cre...
Scientific concepts concerning the characteristics of graft polymerization to oriented polymeric materials and p~lymer-anal~g transf~rmati~ns ~f the graft p~lymer were elab~rated based ~n systematic studies. The principles of fabrication of sorption-active fibre materials Of different ~,pes based on graft copolymers and the most important directions of their use were formulated.The consequences of human technological activity has sharply worsened the environmental situation, making environmental protection an urgent modern problem. One direction in the complex solution of these problems is to develop highly efficient processes for scrubbing of industrial gas-air emissions and cleaning ofwastewaters. Sorption materials, used to prevent further environmental pollution and ensure rational resource management, are playing an important role in the creation of such processes.These materials include chemisorption fibres with a developed specific surface area which is more than one order of magnitude greater than the surface area of granulated sorbents. A comparison of the geometric surface area of fbres and granules gives an idea of the advantage of fibre sorbents over granulated sorbents, manifested by a higher rate of chemisorpticn and greater completeness of removal. In addition, the variety of forms of use of fibre sorbents favors the rational organization of technological processes.The analysis of the scientific and technical literature on fabrication of chemisorption fibres revealed the following methods:-spinning of fbres from blends of fibre-forming polymers with nonfibre-forming polymers containing ionogenic groups;-synthesis of fibre-forming copolymers containing functionally active groups and fabrication of fibres from them; -incorporation of functionally active groups in the fibre via reactions in the polymer chains; -modification of fibres by graft polymerization of ionogenic and nonionogenic monomers with subsequent polymeranalog transformations of the graft chains.Spinning of chemisorption fibres from polymer blends is a relatively simple method. However, the difficulties of obtaining stable spinning solutions from blends of fibre-forming and nonfibre-forming polymers and the possibility of washing out the sorption-active component of the fibre make it necessary to conduct an additional operation of formation of a threedimensional spatial network in the fibre [1,2]. Moreover, this method can be used together with other variants for production of sorption-active materials.The method of spinning fibre chemisorbents from copolymers with chemically active groups in the main chain has been widely used in fabrication of chemisorption fibres of the VION group [3,4]. In this case, acrylonitrile is usually usedas the fibre-forming component, and the composition of the ionogenic comonomers responsible for incorporation of sorptionactive groups in the structure of the fibre is relatively varied. This concerns methylvinylpyridine (MVP), vinylimidazole, sodium p-styrenesulfonate, and others [3,[5][6][7][8]. The fibres...
A unique method for producing Polikon cation-anion exchange mosaic materials has been proposed. The materials were prepared by the polycondensation filling of polymer composites and via synthesis and curing of a weakly basic anion exchanger and a strongly acidic sulfonated cation exchanger on the surface and in the structure of a fibrous novolac phenol-formaldehyde matrix. Molecular models that characterize the chemical composition of the developed composites are given. The effect of the composition that facilitates the formation of a material with stable performance characteristics has been studied. The cause-and-effect relationships of the structural, physicochemical, and operational properties of the heterogeneous cationanion-exchange mosaic materials Polikon under thermomechanical action at the stage of polymer matrix curing were investigated. Empirical equations that refine these relationships were obtained. The morphology and internal structure of the test heterogeneous membranes were characterized by scanning electron microscopy and energy-dispersive elemental analysis. The viscoelastic properties of the samples were studied by dynamic thermomechanical analysis.
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