Novel dispersant‐free disperse dyes containing polyethylene oxide moieties: Synthesis and eco‐friendly dyeing on polyethylene terephthalate fabrics

Abstract

To reduce pollutant emission during dyeing process with disperse dyes, novel disperse dyes containing polyethylene oxide moieties were synthesized. The amphiphilic PEG 400 was engaged in nucleophile substitution with prepared N‐ethyl‐N‐phenylglycinoyl chloride to give coupling component containing polyethylene oxide. Diazonium salts were reacted with synthesized coupling component to obtain aimed eco‐friendly disperse dyes. Fourier transform infrared and 1H‐nuclear magnetic resonance method were used to manifest structures of synthesized dyes and their intermediates. These dyes were applied on polyethylene terephthalate (PET) fabric using traditional high temperature dyeing method under pressure. Dyeing process with and without dispersants were compared, the synthesized dyes showed no dependency on dispersants. Dyed PET fabrics using dispersant‐free methods exhibited excellent levelness, excellent washing and rubbing fastness. Quantum simulations were applied to evaluate structure–property relationship of designed dyes. The optimized geometries of designed dyes and electrostatic potential energy diagrams of molecules were simulated by density functional theory method to explain dye‐fiber interaction. The designed dispersant‐free disperse dyes exhibited no dependency on dispersants and excellent rubbing and washing fastness. Reduction of dispersants could help to eliminate environmental damage related to discharge of effluent containing dispersants.

Effect of Dispersant on Disperse Dyeing in Silicone Waterless Dyeing System

“…The hydrophobic chain of the dispersant would adsorb on the surface of the dye. Because the hydrophilic chain is the carboxylic anion, its charge is a negative charge, which will result in the mutual exclusion of the negative charges between disperse dyes [ 48 , 49 ]. Therefore, there is a dispersion effect between disperse dyes.…”