Sustainable dyeing of nylon fabric with acid dyes in decamethylcyclopentasiloxane (D5) solvent for improving dye uptake and reducing raw material consumption

In this investigation, a solvent dyeing approach was studied to minimize the consumption of water and dyes and to reduce waste effluent by the use of Decamethylcyclopentasiloxane (D5) solvent. To analyze D5 solvent ability to penetrate nylon fiber, XPS analysis was carried out. The feasibility of the use of D5 solvent as dyeing media was also assessed by measuring the effect of D5 processing on fabric chemical, thermal, and crystalline properties by FTIR, TGA, DSC, and XRD analysis. The effect of D5 solvent processing on the mechanical properties of nylon was analyzed by measuring the change in fabric strength and elongation. The basic dyeing procedure for nylon with acid dyes has been developed. It was found that D5 can penetrate the nylon fiber interior and both aqueous as D5 solvent have a similar effect on fabric properties. When nylon fabric was dyed in D5 solvent with acid dyes, 100% dye exhaustion was achieved for all three dyes. By replacing water with D5 solvent as dyeing media for AR249, AB83, and AO67 dyes, the color strength reached 11.44, 25.24, and 19.07 from 7.47, 19.18 and 15.48, respectively. Furthermore, the same D5 bath, without recycling or purification was used successfully in 5 repeated dyeing cycles as no process auxiliaries were added in dyebath. Therefore, this compatibility of D5 with existing acid dye range and dyeing machinery makes it readily applicable for bulk scale production. (c) 2020 Elsevier Ltd. All rights reserved.