| Abstract: | The influence of carriers on the diffusion of disperse dyes in polyester fibre has been studied. The 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 with increase in temperature, and the rates of decrease increase with increase in the activation energies of diffusion of the dyes when no carrier is present. The presence of carrier reduces the activation energies of diffusion 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 the existence 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. |
