Enhanced Mathematical Modeling of DOP Plasticizer Migration from PVC into Liquid (Methanol)

Polyvinyl chloride, commonly abbreviated PVC is a rather hard and rigid material. In order to extend its use it requires additives during the manufacturing process which are referred to as plasticizers, among them the Dioctyl Phthalate (DOP). This latter has a tendency to escape from the PVC matrix specially when in contact with liquids. In order to analyse this phenomenon we use the classical equations of mass diffusion (Fick’s second law). However this method leads to results which are not always in good agreement with experimental ones, especially when the concentration of plasticisers is high. This situation requires the elaboration of an enhanced mathematical model that can deal with this particular type of forced diffusion characterized by the contact with a liquid and particular boundary conditions. The validation of the proposed model was obtained by comparing the theoretical results obtained with the model and those obtained by experiments.