Effect of <scp>PEG</scp>‐400 on dyeing properties of cotton fabric in non‐aqueous medium system

Abstract Traditional reactive dyeing has the technical problems of high water consumption and high pollution. In this article, the effect of polyethylene glycol 400 (PEG‐400) on the dyeing properties of cotton fabrics with high concentration reactive dyes in non‐aqueous medium was studied. Initially, the effects of PEG‐400 on colour strength ( K/S ) and colour fastness of dyed fabric with reactive dye are systematically discussed. In addition, the effect of PEG‐400 on the hydrolysis properties of reactive dyes was analysed by high‐performance liquid chromatography (HPLC). At the same time, the molecular interaction force between the dye and PEG‐400 was analysed by ultraviolet‐visible (UV‐visible) spectroscopy. The results showed that when PEG‐400 concentration was 3.0 g/L, K/S value of dyed fabric (5.0%, on weight of fabric, owf) was increased by 33.5%, and is much higher than dyed fabrics without PEG‐400. HPLC and UV‐visible analysis showed that the addition of PEG‐400 effectively reduced the hydrolysis rate of dye II containing two vinyl sulfone reactive groups, which was converted from C.I. Reactive Black 5 containing contains diethylsulfone sulphate group. Its hydrolysis rate was reduced by 20.9%. PEG‐400 also decreased the aggregation degree of high concentration reactive dye, and increased the solubility of reactive dye. This method has certain universality. Therefore, using PEG‐400 as an additive is an effective way to improve the dye uptake of reactive dyes in non‐aqueous medium dyeing system and realise cleaner production.