Absorption Kinetics of Direct Dye on Cotton from Finite Baths

Absorption time curves from finite baths are determined for untreated and cross-linked cotton fabrics dyed with Direct Red 81 under different conditions. A new method is described for kinetic analysis of absorption time curves. Structural coefficients, electrical coefficients, and dyeing rate constants are determined from the time curves. Crosslinking reduces the electrical coefficients, dyeing rate constants, and activation energy, but increases the structural coefficients (decreases the pore size). The structural coefficient is only affected by crosslinking in this study. The electrical coefficient and dyeing rate constant values are affected very little by dye concentration in aqueous solution in the cases of crosslinked and untreated cotton. However, both electrical coefficient and dyeing rate constant are affected by dyeing temperature and liquor ratio in the two cases.