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The kinetic and thermodynamic parameters of polymer-analog conversion of the graft copolymer of polycaproamide and polyglycidyl methacrylate with sulfamic acid (initial rate, duration, and effective activation energy) were determined. It was shown that the values of the initial rates correlate well with the concentration of the sulfamic acid reaction solution. The formation of a new derivative of the PCA-PGMA graft copolymer containing functionally active amino and sulfo acid groups was confirmed by the data from chemical and analytical analysis and IR spectroscopy. A method was developed for obtaining a sorption-active fibrous polyampholyte containing functionally active amino and sulfo acid groups with SEC HCl = SEC NaOH = 0.895 mmole/g.The wide use of sorption processes, including use of chemisorption fibres characterized by high sorption rates and preservation of the strength properties in repeated regeneration, is one direction in comprehensively solving environmental problems [1][2][3][4].The characteristics of synthesis of polycaproamide copolymer derivatives with sulfamic acid, whose functional groups are capable of donor-acceptor and ion-exchange reactions with heavy metal ions, were investigated here to obtain fibrous polyampholytes of new composite composition.Selection of the method of obtaining polyfunctional compounds based on graft polymerization of nonionogenic monomers followed by polymer-analog conversion of the graft chains was predetermined by its high processability among existing processes [2]. We investigated polycaproamide fibre modified by grafting polyglycidyl methacrylate, the graft copolymer of polycaproamide and polyglycidyl methacrylate (PCA-PGMA) in the ratio of 56:44.The PCA fibre was modified in the experimental conditions in a setup with forced circulation of the reaction emulsion containing glycidyl methacrylate, a nonionogenic surfactant, and the components of a redox system through a layer of the fibre tightly packed in the perforated cylinder of the apparatus. Due to the high conversion of glycidyl methacrylate (98-99%) and the grafting efficiency (99%), the process for obtaining these graft copolymers can be assigned to zero-waste technologies.The polymer-analog conversion of the PCA-PGMA graft copolymer was conducted with a functionally active modifier -sulfamic acid -in heterogeneous conditions by treating the graft copolymer with aqueous solutions at a hydromodulus of 30 ml/g. Since sulfamic acid is limitedly soluble in water, the sulfamic acid solutions with a concentration of 1 to 4 M were obtained by dissolving it at 60-80°C. Due to possible crystallization of sulfamic acid, the reaction products were repeatedly washed off with hot water (80-90°C) to remove the unreacted acid. The occurrence of the reaction of the PCA-PGMA graft copolymer with the sulfamic acid was judged by the content of titrimetrically determined nitrogen and SO 3 H groups in the products of the polymer-analog conversions and the IR spectroscopic data.Moscow State Textile University.

The sorption of nickel and cadmium ions by a fibrous complexing resin containing functionally active amines was studied. The principal kinetic and concentration characteristics of the processes and the coordination properties of the resulting complexes were determined.Sorption technologies play an important role in solving ecological problems, in particular, purification of wastewater and atmospheric releases. Polymeric sorbents in the form of ion-exchange resins and chemically absorptive fibers have been used the most in these processes [1,2]. It is noteworthy that fibrous sorbents have several advantages over granular ion-exchange resins despite their lower capacities. The kinetic parameters of the sorption and desorption processes are greater owing to a more developed specific surface area. The apparatus configuration for the sorption processes can be widely varied because of the variety of shapes of the fibrous material. The resistance to breathing in respirators is reduced significantly if a fibrous filtering element is used. They are mechanically stronger.The problem of extracting and concentrating heavy metals, in particular, from wastewaters of electrochemical and etching manufacturing, has recently become especially important both ecologically and economically. The discharge of wastewaters after plating chromium and zinc; passivation; plating cadmium, nickel, and copper; and etching causes irreparable damage to the ecology and also economic losses due to the loss of pure water and valuable chemicals.Heavy metals (nickel, cadmium, lead, chromium, etc.) are some of the most dangerous contaminants. Their compounds are highly toxic and capable of accumulating in various components of the ecosystem, including in living organisms. In contrast with other chemical components in the composition of natural waters, they do not decompose but only change speciation as the physicochemical conditions of the medium change.The most common methods at present for purifying wastewaters use reagents, membranes, electrochemistry, and flotation. They do not provide purification of wastewaters over a broad concentration range to the maximum allowable concentration (MAC) and maximum allowable release (MAR). Methods based on combinations, e.g., of reagent and chemical sorption methods (by ion-exchange and complexation mechanisms), are most promising [3,4].

In studying heterophase alkaline hydrolysis of ester groups in graft PMMA chains, the role of the structure of the polymer in the macromolecular reaction in the solid phase was revealed. A decrease in the degree of conversion of graft PMMA with an increase in its content in PCA-PMMA graft copolymer, caused by a change in the packing density of the graft chains, was established. The highest degree of saponification was attained in using graft copolymers containing 25-35% graft PMMA. Chemisorption, carboxyl-containing polycaproamide fibre with a SEC for NaOH of 1.3 mmole/g was obtained as a result of saponification of PCA-PMMA graft copolymers.Heterogeneous processes for synthesis of sorption-active polymer derivatives that take place during reactions in the chains of graft copolymers are important not only for accumulating experimental data on reactions in the surface layers of polymers but also for obtaining new chemically modified polymeric materials [1][2][3].Chemical modification of polymeric materials that provides for incorporation of sorption-active groups is a very promising method of obtaining fibrous sorbents with respect to reaching a certain level of functional properties and technological effectiveness of the process itself both in the stage of synthesis and in the conditions of sorption [4,5]. Methods based on graft polymerization of ionogenic monomers to fibrous materials and polymer-analog transformations of graft copolymers are especially effective. The use of these methods allowed developing the principles of technology for fibrous complexes of different functional composition [6][7][8]. The positive experience in obtaining amine-containing chemisorbents from graft copolymers with polyglycidyl methacrylate (PGMA) makes the use of graft copolymers of polycaproamide and polymethyl methacrylate (PCA-PMMA) attractive for fabricating fibrous sorbents of acid character. We investigated the characteristics of synthesis of carboxyl-containing derivatives of graft copolymers of PCA and PMMA to fabricate fibrous sorbents.We investigated polycaproamide fibre modified by grafting with polymethyl methacrylate as the surface layer. Our previous studies on the example of PCA-PGMA graft copolymers was the basis of the notion concerning the surface distribution of PMMA in a polyamide matrix [9], where the fibre becomes hollow after elimination of the polycaproamide from the modified fibre (Fig. 1).PCA and PMMA graft copolymers were synthesized by radical graft polymerization in the presence of the Cu x -H 2 O 2 redox system with fixation of the copper complex in the fibre. Since methyl methacrylate is limitedly soluble in water, the graft polymerization reaction was conducted in an emulsion. The nonionogenic surfactant Neonol in the amount of 0.2% in solution was used as the emulsifier. According to the distribution histogram, the aqueous emulsion of methyl methacrylate was characterized by relatively good stability at room and high (80°C) temperatures.Graft polymerization was conducted with a 0.8 M concentration...

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