Neutral dyeing of polyacrylamide - hydrazine treated cotton with reactive dyes

Cotton fabric was treated with the optimum concentrations of polyacrylamide and hydrazine, dried and cured. The morphological changes occurred were investigated. The pretreated fabric was then dyed with commercial reactive dyes under neutral pH in the absence of any electrolyte. Such dyeing was also carried out with various reactive dyes using different dyeing sequences. The dyeability and fastness properties of the modified and dyed samples were assessed and compared with those of the conventionally dyed sample. It is observed that the simultaneous polyacrylamide-hydrazine treatment and dyeing enhances the dyeability of cotton at neutral pH with a series of commercial reactive dyes. Polymer-aided reactive dyeing improves the wrinkle recovery and may eliminate the subsequent wash-n-wear treatment. A probable mechanism for dye fixation is proposed.