Influence of Added Electrolytes on Kinetics of Dyeing of Formalized and Acid-treated Formalized PVA Fibers

Abstract

The influence of sodium halides on the kinetics of the dyeing of formalized ( I ) and acidtreated formalized (II) PVA fibers with direct dye has been studied at 80°C and 90°C. Each dyeing was made in an infinite bath with 3x10-5 moll/ of Congo Red and with 0.1 mol/l of sodium halide. The apparent diffusion coefficient (D) (Table 2) and the apparent rate constant of dyeing (K) (Table 3) decreased with an increase in degree of formalization of the fiber. These values decreased gradually in the order NaF<NaCl<NaBr<NaI, but the equilibrium sorption of dye (C.. ) (Table 1) increased in the order NaF<Nael<NaBr<NaI. The D, K, and Cm values for II were markedly larger than those of I. The kinetics of the dyeing of I and IT with direct dye appear to be appreciably affected by the inorganic electrolytes (sodium halide) and by the cross-linking formed in the formalization reaction of the polymer.