Dyeing Kinetics of CI Acid Orange 7 in Multiple Layers of a Chemically Modified Wool Fabric

摘要

When the concentration distribution of an acid dye in multiple layers of a chemically modified wool fabric is investigated, the concentration distribution curves have a sigmoidal shape. The adsorption sotherm is approximately described in terms of a Langmuirtype adsorption model. The dyeing rate curve shows the sorptiondelay during the initial stage of dyeing due to the diffusional boundary layer. We assume that the relationship between the diffusion coefficient D_f, dye concentration C, and constant α takes the form D_f=D~o_f exp (αC). The diffusion parmeters are estimated in such a way that the experimental data fit the theoretical curve of the concentration distribution based on the diffusional boundary layer model. The surface concentrations of the dye in multiple layers do not depend on the dyeing time, and they equal the equilibrium uptake. The constant surface concentration is explained by the affinity of the dye to the fibers.