DEVELOPING AN EQUILIBRIUM EQUATION FOR DIRECT DYE MIXTURES ON CELLULOSE

An equilibrium equation has been developed to correlate data for direct dye/cotton systems containing single dyes, mixtures of two dyes, and cotton fibers containing carboxyl groups. The data for Direct blue 1, red 2, red 81 and yellow 12 at 90-degrees-C can be explained in terms of a modified Langmuir equation that can account for positive and negative dye interactions on the fiber. Standard chemical potentials are tabulated and sorption isotherms are plotted for the dye systems evaluated.