| The dissertation studied catalyzing actions of sodium hypophosphite between polycarboxylic acid and cotton cellulose. We defined free carboxylic acid, covalently bound free carboxylic acid and percentage of ester carboxyl groups forming crosslinks on the cotton, and qualitatively as well as quantitatively analyzed the relationship of their concentrations with curing temperature and the effect of their concentrations on esterifying reaction by Fourier transform infrared spectrum analysis, acid-base titration and phosphorus detection.With the same methods, we analyzed the role of sodium hypophosphite in anhydride intermediate-forming step and in esterification step and the effect of finishing bath pH on anhydride intermediate formation and esterification; compared the effect of finishing systems with and without catalyst on monoester-forming, diester-forming critical temperature, percentage of ester carboxyl groups on cotton and wrinkle recovery angle of treated cotton fabric.We demonstrated that the reaction course of sodium hypophosphite varies with different curing temperature, that is, different intermediates produce as curing temperature changes.Moreover, we theoretically analyzed the ability of various intermediates to esterify cotton cellulose.Based on catalyzing hypothesis of sodium hypophosphite, we explored and studied a non-phosphorus catalyst---sodium nitrilotriacetate. At first, we made clear the effect of concentration of nitrilotriacetic acid and the mol ratio of nitrilotriacetic acid to base on properties of fabric; then, optimized the formulation by orthogonal experiment with three levels and four factors, the mol ratio of nitrilotriacetic acid to base, the concentration of nitrilotriacetic acid, curing temperature and curing time, respectively. The indexes are wrinkle recovery angle, break strength and whiteness of treated fabric. Wrinkle recovery angle, break strength, whiteness of fabric and resistance of wrinkle recovery angle to wash were compared between sodium nitrilotriacetate catalyzing system and other catalyzing system. Comparisons of dyeing properties were made between fabric finished with the phosphorus-containing system and sodium nitrilotriacetate system. The effect of finished fabric with polycarboxylic acid ondyeing properties of various dyes was catalyzed. Further, kinetic data were calculated and contrasted about two systems. The results are that wrinkle recovery angle and after-wash whiteness of fabric finished with sodium nitrilotriacetate as catalyst are similar to with sodium hypophosphite, break strength and resistance of wrinkle recovery angle to wash are higher than with sodium hypophosphite, Arrhenius activation energy of two systems is equivalent, carve trends of the dying properties of two systems on direct, active, cautic and vat dyes with the curing temperature are accordant.Catalyzing mechanism of sodium nitrilotriacetate system was investigated by Fourier transform infrared spectrum, nitrogen-containing detection, dyeing experiment and other measures. The catalyzing action of sodium ion was validated by comparing the different wrinkle recovery angle of fabric treated in sodium nitrilotriacetate system with and without sodium chloride. We analyzed the respective ratio of nitrilotriacetic acid to 1,2,3,4-butanetetracarboxylic and NaOH, which interact and affect fabric wrinkle recovery angle. Respectively mix the equal mol of citric acid, succinic acid and nitrilotriacetic acid with NaOH in terms of 1:2, 1:2.5,1:3 to act as catalysts, then, researched the catalyzing action of nitrogen element in the light of the different molecular structure of three substances.Sodium nitrilotriacetate catalyzes not only the anhydride intermediate formation but also esterification. Sodium nitrilotriacetate is an amphion and serves both as Lewis acid and Lewis base to make BTCA conversing to its anhydride which is attacked by nitrogen atom of sodium nitrilotriacetate to form a intermediate esterifying the cellulose. In the esterification reaction the chemical pr... |
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