The Absorption of a Disperse Dye by Cellulose Acetate in the Presence and Absence of Butanol

Abstract

The absorption of Disperse Red I by secondary cellulose acetate yarn has been studied. The experiments were run in such a way that the dye was present in true solution and the concentration of dye remained constant during the absorption process. The solvents were water and water with various amounts of butanol added ; the temperature was con trolled at either 50° C. of 65°, C. Both rate and equilibrium measurements were made. The rate measurements were consistent with a diffusion process having a rate constant in the range of 1 X 10^-11 cm.²/sec.

The action of the butanol was complex. It caused a minimum in the equilibrium uptake of dye and in the rate of attainment of equilibrium as its concentration in the dyebath increased. Possible reasons for this behavior are discussed. Either competition for absorption sites between dye and butanol or complex formation in the dyebath are advanced as possible reasons for the initial decrease ; swelling with increased accessi bility is advanced to account for the increase after the minimum.