The "protective "function of the polymer substrate in oxidative treatments of linen cloth was revealed. It was found that the stability of the chromophore structure of direct and active dyes on flax celhdose in both acid and basic medium is much higher than in aqueous sohttion and printing composition. The "protective" effect of the polymer in oxidative degradation of flax celhdose natural dyes is manifested to a lesser degree due to the effective destruction of cellulose dye satellites in conditions of discharge printing of grey linen.Investigation of the problem of oxidative degradation of synthetic and natural dyes in flax fibre is of great practical importance due to the increased interest of manufacturers in production of ecologically clean textiles from naturally dyed fibres.A dye is usually not an inert filler of the polymer medium, and intermolecular interactions of different types, up to formation of covalent bonds, arise between the dye molecules and macromolecules of the polymer substrate. The character of these interactions can significantly affect the course of industrial processing and use of grey linen. The urgency of the problem is especially great in examining the theoretical and technological aspects of coloring materials made of naturally dyed fibres by discharge printing, developed in the Department of Chemical Engineering of Fibre Materials at Ivanovo State University of Chemical Engineering [1].In the course of the studies, it was found that creating conditions for efficient bleaching of natural dyestuffs and ensuring the stability of the chromophore structure of synthetic dyes in the combined presence of an oxidant in the discharge composition is the most important, frequently difficult to attain task in conditions of color discharge printing on grey linen cloth.The rate of oxidative degradation of direct, active dyes and lignin in solution and in flax cellulose with respect to the conditions of color discharge on Art. 407 and 416 cloth was comparatively evaluated in the present article.The stability of the chromophore structure of these dyes with respect to oxidative degradation was evaluated spectrophotometrically in the visible and UV regions of the spectrum using SF-18, Specol-ll, and Specord-40 spectrophotometers.The values of empirical parameter n characterizing inhibition of oxidative degradation caused by the specific features of its occurrence in a solid polymer matrix were determined with the kinetic curves of the optical characteristics of colored solutions and textile materials as a function of time ( Figs. 1 and 2). This kinetic situation is described by the function [2] f(t) = 1 / (1 + W~ I/', n where t is time; W 0 is the initial rate of oxidative degradation; n is the rate inhibition coefficient.This analytical function covers a wide range of diminishing functions as a function of the values of inhibition coefficient n. When n ~ 0 (this situation occurs in aqueous medium), the function assumes the shape of a logarithmic dependence on Ivanovo State University of Chemical E...
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