THEORETICAL AND EXPERIMENTAL-STUDY OF DIOCTYL PHTHALATE TRANSFER FROMA PLASTICIZED PVC DISC DIPPED INTO AN EDIBLE OIL

When polymer and liquid are contacted with each other, as in packaging , some mass exchanges may occur, which constitute a major drawback whe n the liquid is a foodstuff or blood. However, these mass transfers in the polymers can appear as very interesting from the industrial point of view, if one is able to use and control them. It is then necessary to have a good knowledge of these transfer processes which are contro lled by diffusion. Dioctyl phthalate (DOP) migration into an edible oi l was studied under worst conditions: high plasticization level (50% b y weight) and temperature(30 degrees C). The quantitative analysis of DOP in a such complex liquid medium and in the PVC itself was made eas y by the use of the radioactive tracer technique. A simplified mathema tical model, obtained by neglecting the oil transport in the PVC, was evaluated. This model based on the research of a finite differences ex plicit solution allows to reproduce for the DOP, the concentration pro files in the polymer and the kinetics of transfer in the oil, with a P -value less than or equal to 0.001.