Statistical optimization of self-cleaning technology and color reduction in wool fabric by nano zinc oxide and eco-friendly cross-linker

The stain resistance and intrinsic hydrophobic features of wool are the most important problems which have negative impacts on various aspects of wool and prompt scientists to find a solution over the past decades. Zinc oxide nanoparticles (ZnO-np) were successfully synthesized and stabilized on natural protein wool using the impregnation process with butane tetra carboxylic acid (BTCA) as eco-friendly cross-linker. In this research, these particles were linked to wool surface by BTCA and also sodium hypophosphite was used as a catalyst. The self-cleaning technology of ZnO-np deposited on the wool fabrics was followed by degrading of Direct Blue 71 and Disperse Red 1 as synthetic stains and also determined by degrading rate of food stains such as coffee and black mulberry under the ultraviolet irradiation. The hydrophilicity was monitored by water drop absorption time. The central composite design was used for different variables based on Design of Expert software. The analysis of variance was utilized to obtain the optimum models for wool with maximum color reductions and minimum absorption time. The presence of ZnO-np on the wool surface was confirmed with scanning electron microscopy. Further transmission and absorbance spectra validated the UV protection properties of ZnO-np-treated wool. The results showed that increasing the amount of ZnO-np leads to enhanced reduction of synthetic color stains than food color stains on the treated wool fabric, while the fabric became more hydrophilic.