Studies on Assessment of Reactive Dyeings from Viewpoint of Eco-Textiles

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(1):Photosensitized oxidation of four triphenodioxazine (TPDO) reactive dyes and a copper phthalocyanine (CuPc) reactive dye on cellulosic films by Rose Bengal (RB) was examined in the aqueous solutions under aerobic conditions. No aggregation effect was observed on the fading of TPDO dyes and a CuPc dye on cellulose, but the concentration or filter effect.(2):The stability of seven reactive dyes on cellulose immersed in sodium peroxoborate (PB) solution (UK-TO solution) containing TAED was examined by use of cellulosic films at 60℃. The dye loss from dyed cellophane films was attributed to three contributions : (a)alkaline hydrolysis of dye-fiber bond, (b)oxidative fading of dye chromophore by peroxides, and (c)cellulose degradation accelerated by PB and TAED. The alkaline hydrolysis of dye-fiber bond and the cellulose degradation in UK-TO solution were the dominant factors to cause the dye loss. The dye oxidation in UK-TO solution was a minor factor in the dye loss mechanism. The phy … More sical bonding of dye molecules reinforced the dye-fibre bond stability in UK-TO solution.(3):Photostability of nine vat dyes on cellulosic films was examined. The ease (k_0) with which the dyes were photo-oxidized was estimated by the relative fading of vat dyes on cellophane immersed in aqueous Rose Bengal solution on exposure, a condition resulting in only the photo-oxidative fading. The values of k_0 were small, compared with those of reactive dyes, while those of f comparable. The lightfastness of nine vat dyes on dry cotton fabric had close correlation with log (f k_0).(5):The enthalpy of formation for the azo and hydrazone tautomers of phenylazonaphthol sulfonic acids was estimated both in the gaseous phase and in water using the PM5 and COSMO method.(6):With respect to Orange I and II, azo-hydrazone tautomerism of the undissociated and dissociated species was analysed estimating their enthalpies of formation in both the gaseous phase and water using the PM5 method.(7):Photofading of fifteen reactive azo dyes on cellophane under wet conditions was examined to estimate the essential properties. A linear correlation between the logarithmic product, log (f k_0), and the LF ratings of dyes on dry cotton fabric was found when plots of reactive dyes with low LF and those of the vat dyes examined in a previous paper were added because the ratings of eleven red dyes out of fifteen dyes examined had a narrow range. Less