Predicting diffusion behavior of disperse dyes in polyester fibers by a method based on extraction

The diffusive behavior of dye molecules in a polymer were typically observed during the impregnation of the dye in a polymer, and this method combines phenomena that occurs in both the fluid and polymer phases. However, the dissolution of the dye in a fluid can cause inadequate resistance in the overall mass transfer, leading to errors in observing the diffusion behavior. Thus, in this study, we proposed an extraction-based diffusion coefficient measurement method that fundamentally minimizes errors in the dissolution process. The new methodology based on extraction can be utilized more easily without the consideration of the dissolution step. Moreover, the diffusion coefficients of dyes in polyester fibers were consistent with those determined by the WLF model over a range of temperatures and pressures. The extraction-based methodology can be easily utilized to measure the solute diffusion behavior in a glassy polymer or systems with slow dissolution rates.