Dyeing Cotton with a Reactive Dye from Polar-Nonpolar Solvent Systems

Abstract

An attempt was made to dye an aqueous alkali swollen cotton with CI Reactive Red-31 from polar/nonpolar solvent mixtures. For this purpose acetone was selected as the nonpolar solvent and the various polar solvents were water, formamide, di methylsulfoxide, dimethylformamide, and dimethylacetamide. At a suitable ratio of solvent mixture and alkali concentration used for cotton preswelling, it was possible to get 100% dye bath exhaustion and dye fixation of 79-82%, except from dimeth ylformamide-acetone and dimethylacetamide-acetone solvent mixtures. The propor tion of polar-nonpolar solvent necessary to get highest dye bath exhaustion and dye fixation was dependent on the dielectric constant of the polar solvent. Some of the polar solvents were good swelling agents for cotton as indicated by their imbibition values and high dyebath exhaustion. It was therefore possible to carry out dyeing without water preswelling; however, since the alkali used for dye fixation was insoluble in the solvents, aqueous alkali preswelling was essential. Concentration of alkali re quired during preswelling to get maximum dye exhaustion and fixation was different for different polar solvent-acetone mixtures. This was attributed to the desorption and readsorption of alkali from the solvent mixtures to different extents.

Non‐aqueous dyeing of cotton fibre with reactive dyes: A review

“…In 1983, Chavan and Rao reported the dyeing of water‐swollen, solvent‐exchanged cotton with three acid dyes with varying numbers of sulphonic acid groups. In the same year, an attempt was made by Chavan and Subramanian to dye aqueous alkali‐swollen cotton with reactive dye from polar/non‐polar solvent mixtures. The selected non‐polar solvent was acetone while several polar solvents such as water, formamide, dimethylsulphoxide (DMSO), DMF and dimethylacetamide were used.…”

Non-water dyeing process of reactive dyes in two organic solvents with temperature-dependent miscibility

“…As we all know, commercial reactive dyes react with water as a side reaction during the dyeing process. To avoid this limitation, a lot of non-water dyeing processes have been developed by many researchers, such as the supercritical dioxide dyeing process, [1][2][3][4][5][6][7] reverse micelle dyeing process, [8][9][10][11][12][13][14][15][16] solvent dyeing process [17][18][19][20] and so on. However, there are many disadvantages that seriously hinder the application of these dyeing processes.…”

“…16 For the solvent dyeing process, a 100% exhaustion ratio could be reached but only a 85% fixation ratio has been reported in the literature. 20 In addition, the separation and re-use processes for organic solvents are energy-and time-consuming, making them unacceptable. When we repeated the non-water dyeing process using a binary-solvent system, we found an exciting phenomenon that some solvents have unique miscible properties.…”