One-Step Pad Dyeing and DP Finishing of Cotton: Part 2. Mechanism of Dye Fixation Using DMDHEU

This paper is a follow up to previous work from these laboratories, which led to a method for simultaneous reactive dye fixation and DMDHEU finishing of cotton at significantly higher shade depths ( K/ S values) than previously reported. The introduction of a steaming step prior to curing was critical to achieving high shade depths. The goal of this report is to present the mechanistic basis for these results. In this regard, results from conducting reactive dye/DMDHEU chemistry on a solid surface and from solvent extractions of dyed cotton before and after powdering indicate that dye fixation occurred by DMDHEU-induced entrapment rather than dye-fiber dye-DMDHEU bond formation.