Towards environmental protection and safety coloration process in wool fibers: Role of disperse reactive dyes structure

Abstract

Traditional wool fibers dyeing uses a huge amount of water and energy, and relies on lots of chemicals, which produces huge amounts of lower-biodegradable wastewater, and poses a great threat to the water environment. Here, to investigate the role of disperse reactive dyes structure on the dyeing properties, a sustainable waterless dyeing of wool fibers was investigated with four synthesized disperse reactive dyes by using supercritical CO2 as a non-aqueous dyeing medium. The effects of dyeing time, pressure, temperature and dye concentration on the dyeing properties were discussed. The results showed that K/S values up to 5.5 under the optimal dyeing condition of 383.15 K, 23 MPa, and 70 min were obtained, indicating shorter reaction time and higher K/S values compared to similar studies. Moreover, excellent colorfastness to soaping and rubbing up to 4–5 was displayed since nucleophilic substitution reaction occurs between the C atom on the triazine group of disperse reactive dyes and -NH2 on the cysteine of fiber macromolecules. This study provides an environmental protection and safety coloration process to produce high-quality wool fiber products by establishing the relationship between structure of disperse reactive dyes and dyeing properties of wool.