Thiourea dioxide-mediated surface functionalization: A novel strategy for anti-felting and dyeability improvement of wool

Wool, mainly composed of keratin, is a relatively high-grade textile material. Its inherent disadvantage such as high shrinkage and poor dyeability caused by the complex scale structure has puzzled people for a long time. Removing or breaking the surface scales of wool fibers in a simple, effective, and environmentally friendly way has attracted growing attention in recent years. Herein we proposed a thiourea dioxide (TD)-based method that could effectively remove the surface scale of wool fiber with minor damage to its internal structure. This was verified using Allworden reaction, scanning electron microscopy (SEM), XPS, FT-Raman spectroscopy and Ellman's test. Furthermore, the dimensional stability and dyeability were significantly improved. The machine-washable effect can be achieved with the strength loss of merely 5.16% when the TD concentration was 10%. Fluorescence microscopy images further showed that low concentrations of TD could damage the surface scale layer of wool without severe strength loss. This approach is facile, environmentally friendly, and economical, providing a new direction for the surface modification of varied keratin-rich fibers.