Enhancing Dye Adsorption of Wool Fibers with 1-butyl-3-methylimidazolium Chloride Ionic Liquid Processing

In this paper, 1-butyl-3-methylimidazolium chloride ionic liquid (IL) which has good solubility for wool keratin, was employed to treat the wool fibers. The characterization of IL treatment on the wool fibers was first investigated using scanning electron microscopy (SEM), the Allwörden reaction and X-ray diffraction (XRD) analysis. Then, the effect of the IL treatment on the wool adsorption properties for an acid dye was studied through the dyeing rate test. The IL treatment was proven to be an effective process for wool characterization. The scales of the IL-treated wool fibers were eroded and even dislodged when the treatment temperature was increased according to the SEM observations. The Allwörden reaction showed that the epicuticle of wool fibers was damaged and became incomplete after the IL treatment. XRD indicated that the IL treatments could cause the decrease in the degree of crystallinity of wool fibers. Furthermore, the adsorption and diffusion behaviors of the IL-treated wool samples showed that the ionic liquid modification could improve the sorption properties of the wool fibers as represented by the increases in the dyeing rate.