The plasticisation model of dye diffusion: Part 7

Re‐evaluation using the Williams‐Landel‐Ferry equation, of exhaustion/fixation/adsorption data previously reported for four classes of anionic dye onto three different types of wool substrate, revealed that thermally activated dyeing/desorption behaviour is governed by the thermally regulated structural relaxation times of the respective water‐saturated, water‐swollen, water‐plasticised α ‐keratin macromolecule over the broad 25°C to 100°C range of dyeing/desorption temperatures considered. The plasticisation model of dye diffusion therefore offers a satisfactory explanation of the temperature dependent diffusivity of the acid dye, mordant dye, reactive dye and direct dye within the water‐plasticised α‐ keratin macromolecules: the temperature dependent exhaustion/fixation/adsorption behaviour of the various anionic dyes onto wool therefore accords with Free Volume Theory .