Thesis Details

Thesis Title: The Effect of Various Fixing Agents on the Fastness Properties of Direct Dyed Cotton Twill Fabric
Thesis Author: Edward F. Carman III
Abstract: Direct dyes require an aftertreatment when used to dye cotton fabric to improve the fastness properties.. The better the aftertreatment can neutralize the sulfonic acid groups of the dyestuff, the more the wash fastness characteristics will be improved. Currently, metallic salts and formaldehyde derivatives are two of the best type fIxatives. However, because of effluent regulations becoming more stringent and the carcinogenic nature of formaldehyde, alternative fIxatives need to be evaluated. Alternatives to the use of formaldehyde fIxative have been evaluated, these yielding comparable or improved dye fastness properties. Thus, the minimization or elimination of formaldehyde fIxatives is feasible. Previous efforts in this areato improve the performance of the dye fastness properties were conducted, however, some information was misleading and inaccurate. The current research evaluated dyestuffs with the same number of benzene rings, linearity, and azo groups. The variables of the dyestuffs were not only the sulfonic acid groups, but the hydroxyl and methyl groups. The chemistry of the aftertreatments was also known. To accomplish this work, 3/1 cotton twill fabric was dyed with three different direct dyestuffs; Direct Red 83, Direct Red 62, and Direct Orange 26. The fabric was then aftertreated with one of the four fIxatives; formaldehyde condensate, cationic polyamide, quaternary polyimine, and polyamine condensate. A control was used that was dyed, but received no aftertreatment. The fabrics were then tested for wash, crock, and light fastness attributes. Considering the experimental limitations, and with respect to the objectives of the thesis, the following general conclusions were derived. 1. Direct Red 83, which had four sulfonic acid groups, had the best wash fastness properties when aftertreated with the polyamine condensate. 2. Direct Orange 26, which had two sulfonic acid groups, had the best wash fastness when aftertreated with the cationic polyamine. 3. The quaternary polyimine had the best light fastness when used to aftertreat Direct Red 83. 4. No decrease in tensile or tear strength occurred for the fabric at the highest fixative concentration.