DIFFUSION OF A DISPERSE DYE IN THE MULTIPLE LAYERS OF NYLON FABRIC

Abstract

The concentration distribution of a disperse dye in the multiple layers of nylon fabric is investigated. The surface concentration increases with dyeing time. The increase is attributable to the resistance to dye transport across the diffusional boundary layer. The boundary layer parameter (L) and the diffusion coefficient (D_f) of dye in nylon fabric are estimated in such a way that the experimental data fit in with the theoretical curve of concentration distribution based on the diffusional boundary layer model. The estimated values of thickness of diffusional boundary layer (δ_d) range from 0.017 to 0.011cm when the dye bath is stirred at 100-150rpm. As the multiple layer of nylon fabric has spaces or pores between the yarns and also between the individual filaments, it is considered that the dye molecules diffuse through the liquid in the spaces or pores of nylon fabric. Consequently, the observed diffusion coefficient was reasonably explained by assuming the “pore model”: the calculated value agreed well with the experimental one.