Influence of additive organic base on dyeing of cotton fabric under supercritical carbon dioxide using fluorotriazine reactive disperse dye and investigation of optimal dyeing conditions

This paper demonstrates the impact of an organic base on dyeing of cotton fabric using a fluorotriazine-based reactive disperse dye under waterless dyeing conditions with supercritical carbon dioxide (scCO2). The cotton fabric was dyed without pre-treatment. The system parameters, including temperature, pressure, time, and dye concentration, were examined. The systematic variation in the parameters indicated that the optimal coloration was achieved by adding 300 mM of α-picoline as an alkali at 120 °C and 25 MPa under scCO2. The dye structure was determined using infrared and nuclear magnetic resonance spectral data, showed a good agreement with the structure proposed. The morphological structure was partially identical with no damage to the cotton, as determined using scanning electron microscopy. The results indicated that fluorotriazine-based dye has a high coloring behavior, with the color strength, leveling properties, and staining fastness rated at 4–5 in terms of a dyeing medium with α-picoline.