Carrier Dyeing of Polyester Fibre Part III – The Role of Water in Solvent Dyeing

The role of water as an auxiliary in solvent dyeing of polyester fibre has been studied. The addition of water results in a lowering of the glass transition temperature, an increase in the diffusion coefficient and reductions in the energy of activation of diffusion and the entropy of activation of diffusion. The increase in the diffusion coefficient is smaller at higher temperatures and varies from dye to dye, being related to the energy of activation of diffusion. These effects are similar to those reported previously for carriers in the aqueous dyeing of polyester fibre and demonstrate that the role of water in solvent dyeing is similar to that of a carrier in aqueous dyeing.