Surface Chemical Analysis of C.I. Leuco Sulfur Black 1 Dyed Cotton Fabric Sequentially after-treated with Cationic Fixing Agent and Tannin

Previous studies have established that sequential cation-tannin after-treatment on sulfur dyed cotton fabric can improve the oxidative washing resistance against perborate-based laundering regimes. In this investigation, C.I. Sulfur Black 1 dyed cotton fabric was after-treated with a cationic fixing agent (Tinofix ECO) and tannin-based product (Bayprotect CL) and laundered with ISO 105 C09 washing protocol. The dyeings were evaluated for color strength and wash fastness. The surface functionalities and elemental composition of the dyeings were analyzed by using the surface sensitive X-ray photoelectron spectroscopy (XPS) to compare visual changes with surface chemical changes. After-treated and laundered dyeings exhibited higher content of surface sulfur and lower surface oxidation as compared to the untreated counterparts. The S (2p) spectra of after-treated and laundered samples demonstrated reduced over oxidized (S 6+ ) species at 168 eV. The effect of laundering and modification to the surface sulfur dye was related to K/S and % color loss analysis.