Hydrolyzed reactive dyes in the coloration of textile fibers.

摘要

This dissertation pertains to the investigation of an alternative to the destructive decolorization of dyebaths remaining following the application of reactive dyes to cotton. In this study, a group of twenty commercial dyes was used to (1) develop conditions for dyeing nylon and wool with color remaining from applying reactive dyes to cotton, (2) establish relationships between reactive dye structure and the affinity of their hydrolyzed forms for nylon and wool, (3) compare the fastness properties of hydrolyzed reactive dyes and their reactive forms, and (4) identify an analytical technique suitable for characterizing dye structures remaining after dyeing cotton with reactive dyes.; The results of this study indicate that wool possessed higher affinity for hydrolyzed reactive dyes than nylon. Interestingly, it was also found that hydrolyzed reactive dyes possessed higher affinity for nylon than the corresponding commercial reactive dyes themselves. There was, however, no significant difference in the exhaustion of commercial versus hydrolyzed reactive dyes on wool.; Results from structure-performance assessments suggested that molecular structure affects hydrolyzed dye uptake on nylon and wool. Recycled dyes (dyes remaining following application on cotton) having a higher molecular weight and less planarity (high dihedral angle) behaved similar to milling acid dyes, i.e. they exhausted under weakly acidic to neutral pH, whereas the more planar dyes behaved similar to level dyeing acid dyes, i.e. they exhausted better under strongly acidic pH. While molecular weight had little effect on pre-hydrolyzed dye uptake on nylon or wool, it significantly affected recycled dye uptake on both fibers. No significant changes were observed in the fastness properties of wool dyed with hydrolyzed dye versus their commercial precursors.; Negative ion electrospray mass spectrometry (ESI) proved to be an excellent method for characterizing dye structures remaining following the dyeing of cotton with reactive dyes. This technique, when compared with negative ion Fast Atom Bombardment (FAB) mass spectrometry, gave peaks of higher relative abundance in the molecular weight region and better signal to noise ratios.