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Kinetics and mechanism of the graft copolymerization process of acrylamide onto polycaproamide, initiated by the redox system K2S2O8/Na2S2O3 in the presence of the heptaazocyclohexadecine complex of Cu(I) fixed on the polyamide matrix, were studied. The process of graft copolymerization takes place with maximum rate and efficiency at a molar ratio of [Na2S2O3]:[K2S2O8]=4.3. The kinetical parmeters of the graft copolymerization as well as of the homopolymerization during the process of grafting have been determined.

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A new water-soluble derivative of chitosan chitosan oligoethylene oxide sulfonate was synthesized. The ratio and concentration of reacting substances and temperature and duration of the chitosan modification reaction affect the composition and properties of the reaction products. The conditions that ensure a 100% yield of water-soluble chitosan derivatives were determined. Using potentiometric titration and IR spectroscopy, the formation of a new water-soluble chitosan derivative oligoethylene oxide sulfonate was confirmed.The interest of researchers in the study of polymer-analog transformations of chitosan and fabrication of new chitosan derivatives is due to both the unique properties of this polysaccharide and the broad possibilities of chemically modifying it by alkylation, acylation, salt formation, and complexation reactions. The specific features of the chemical structure of chitosan create grounds for fabrication of water-soluble film-and fibre-forming derivatives of different types whose properties are determined by the structure of the added substituents to a significant degree [1][2][3][4][5].To obtain new water-soluble chitosan derivatives, we used reactive ethylene oxide oligomers containing a sulfo group. One of these compounds oligoethylene oxide sulfonate (OES) was fabricated from oligoethylene oxide sodium sulfonate (OES-Na) ( Table 1) by ion exchange.Ion exchange was conducted in dynamic conditions by passing aqueous solutions of OES-Na through a column packed with KU-2-8 cation exchanger. Conversion from the Na form to the H form was monitored by the content of sulfoxyl (SO 3 H) groups in sulfonic acid oligoester (SAOE) by titration with 0.1 N NaOH solution in the presence of methyl red indicator or by potentiometric titration on a pH-340 pH-meter. The error of measurement did not exceed 0.25% at the 0.95 confidence level.The concentration of the initial solution of the oligomer and the rate of its passage through the column significantly affects the completeness of conversion of the salt form of OES-Na into the sulfonic acid form of OES. We investigated the effect of the OES-Na content on the degree of substitution of Na + cation by H + (Table 2). We found that the optimum oligomer content in aqueous solution that guarantees quantitative conversion of the Na form into the H form was 3-6%. The rate of passage of the solution through the column should not exceed 2 ml/min. The sulfonic acid oligoester separated from the solution is a viscous, colorless, transparent substance readily soluble in water.Chitosan preparations with a molecular weight of 4.2⋅10 5 and 1.9⋅10 6 were used to prepare the derivatives containing OES-H residues ( Table 3).The reaction of the amino groups in the chitosan macromolecule with the OES sulfonate groups should primarily take place according to an ionic mechanism. The salts formed are actually a new derivative of chitosan oligoethylene oxide sulfonate (OSC), where the characterization of the composition and properties are of independent interest. OSC was synthesized ...

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SYNOPSISGraft polymerization of methacrylic acid to polycaproamide, initiated by the KzSz08-Na2S203-Cu2+ reversible redox system, has been studied. Kinetic characteristics of graft polymerization have been investigated in a wide concentration range of every component of the initiating system. Cu2+ ions have been found to catalyze graft polymerization in the 1.0 * 10-5-1.2 * 10-4M concentration range, whereas at concentrations higher than 1.2 * 10-4M, Cu2+ ions are involved in the kinetic chain termination. A mechanism of graft polymerization is proposed.

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