Effect of different salts concentration on dyeing behavior of cotton fabric using vinyl sulphone reactive dyes at different temperatures
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Date
2011
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University of Management and Technology
Abstract
This research presents an investigation into the behavior of cotton dyeing by using vinly sulphone reactive dyes at different temperatures and salt concentrations. Among all dyes, reactive dyes are unique class of dye for cellulose fibers due to their good washing fastness, bright shade and versatile dyeing method. These dyes are different due to their chemical nature, because they make covalent bond with cotton fiber. Vinyl sulphone based reactive dye was used to check and compare the effect of four inorganic salts (Na2SO4, NH4Cl, K2SO4, NaCl) along with sodium carbonate Na2CO3 on the change of color strength. 4% shade is prepared from 1% dye stock solution. Under alkaline condition reactive dyes react with cellulose mostly by neucleophilic substitution or addition to form covalent bond. Thus the use of high salt concentration will be lead to high reactive dye fixation which will give excellent color fastness, wash fastness and fastness to rubbing properties. All the dyeing was carried out at four different temperatures 40 ºC, 50 ºC, 60 ºC, and 70 ºC, temperature plays a very vital role in fixation of dye. The whole dyeing was done in High Temperature dyeing machine. Material-to-liquor ratio was fixed at 1:20 for all the experiments during research work but the concentration of salt was varied from 10-40g/L, however the amount of alkali was kept fix i.e. 20g/L throughout the dyeing work. After dyeing all the samples were passed through a washing process which includes cold water washing, hot washing, 0.1% solution of acetic acid rinsing and finally rinsing with 0.1% solution of wetting agent. After washing the dyed cotton fabric was attested by some parameters like color strength (K/S) and color coordinates (L*, a*, b*, C*, h), color fastness to rubbing and color fastness to washing using ISO standards. After this research it is proved that Glauber's salt Na2SO4 has a good exhausting ability to enhance the color strength, hue and all other properties on the fabric. Similarly increase in salt concentration and increase in temperature enhances the fixation of dye molecules on the cotton fabric.
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Keywords
Master Thesis, Cotton Dyeing Behavior, Effects of inorganic Salts, Temparture and Dying