The plasticisation model of dye diffusion: Part 6

Previously published data reported for the temperature dependency of the exhaustion of a mordant dye and acid dye, as well as both the exhaustion and fixation of a reactive dye and adsorption of a direct dye, on three different types of wool substrate, over a diverse range of dyeing temperatures and conditions, were re‐evaluated using the Williams‐Landel‐Ferry (WLF) equation. As the temperature dependent exhaustion/fixation/adsorption of each of the four classes of anionic dye onto each of the respective types of wool substrate adhered to a WLF relationship, the thermally regulated diffusivity of each anionic dye within each type of wool substrate is governed by the thermally activated structural relaxation times of the water‐saturated, water‐swollen, water‐plasticised, α ‐keratin macromolecule. The plasticisation model of dye diffusion therefore appears to provide a plausible explanation of the observed temperature dependency of the diffusivity of the mordant dye, acid dye, reactive dye and direct dye within wool.