A new approach to the study of plasticizer migration from PVC into methanol

A new approach to the study of the migration rate was attempted for dioctylphthalate as plasticizer from solid PVC into liquid methanol. Two different experiments were carried out: first, a classical one by measuring the increase in the plasticizer concentration in solution; second, a new one by measuring the plasticizer concentration inside the solid PVC itself, for different times and for different depths in that solid. Equations of diffusion in unsteady state were found to correlate well with experiments in both cases. Stirring of the solution measured by Reynold's number was found to be important. Measurements were carried out inside the solid PVC, and the profile of the concentration of dioctylphthalate inside the PVC disc was determined at different times. The diffusion coefficient was calculated inside the PVC disc, and it was found to vary with the DOP concentration.