The influence of carriers on the diffusion of disperse dyes in polyester fibre has been studied. m e extent to which the diffusion rate of a dye is increased is independent of the chemical structure of the carrier but depends on the molar concentration of carrier in the fibre and on the chemical structure of the dye. The influence on the diffusion rate decreases wirh increase in temperature, and the rates of decrease increase with increase in the activation energies of diffusion of the dyes when no cam'er is present. The presence of carrier reduces the activation energies of diffision of the dyes, the reduction being related to the decrease in the entropies of activation of diffusion brought about by the plasticizing action of the carrier. This reduction in the activation energy of diffusion leads to theexistence of a temperature at which the presence of carrier would have no effect on the diffusion coefficient of the dye, and above which the presence of carrier would actually reduce the diffusion coefficient. The value of this temperature depends upon the carrier concentration in the fibre and the specific dye.

Aspects of the diffusion of carriers in polyester fibre have been studied using several compounds representative of commercial carriers. The apparent diffusion coefficients, activation energies of diffusion, and entropies of activation of diffusion have been determined. The apparent diffusion coefficients were found to be several orders of magnitude greater than those of disperse dyes, whilst the apparent activation energies and entropies of activation of diffusion were lower. A major difference in the diffusion behaviour of carriers, compared with that of disperse dyes, is the concentration–dependence of the diffusion coefficients of the former class of compound.

E E 0.4--0 > W % 0.3f 9, 0.2 0 V n I ) 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 ofpolyester fibre and demonstrate that the role of water in solvent dyeing is similar to that of a carrier in aqueous dyeing. 0.1

A new method for the extraction o f chrome mordant dyes from wool has been investigated. The method, which involves the use of EDTA in aqueous dimethylformamide, extracts sufficient dye for use in chromatographic identification. The applicability of the method has been studied with eleven selected chrome mordant dyes.