The adsorption behavior and phase transfer catalytic fixation of a special dye SCF-AOL2 on cotton in supercritical carbon dioxide

Supercritical carbon dioxide (SC-CO2) dyeing technique is a powerful alternative method to conventional ones. In this work, the uptake behavior and the build-up performance of a special dye SCF-AOL2 involving a potential reactive group of β-ethylsulfone sulfate on cotton in SC-CO2 was investigated. Particularly, a phase transfer catalytic method, involving series of reactions and a supposed mechanism in a supercritical fixation system was introduced for the special dye fixation by employing a phase transfer catalyst. The results show that the uptake behaviors of the special dye were significantly improved with temperature, pressure and duration in both pure and cosolvent involved SC-CO2 systems. Moreover, the fixation efficiency and the color fastness of the uptake dye on the substrate were notably improved by employing the catalytic fixation method. Furthermore, the dye uptake and catalytic fixation behaviors were also verified with color measurement, dye fixation efficiency, FT-IR analysis and color fastness evaluation.