The migration of plasticizers into petroleum oils

The importance of the migration of plasticizers, and the basic differences due to types of contact, are analysed. The migration of phthalate plasticizers from plasticized PVC to several petroleum oils was studied quantitatively by a method based on labelled plasticizers and measurements of the radioactivity of the medium. The results are compared with those obtained by methods of radioactivity and weight loss; differences are discussed. In most cases, the migration of plasticizer is accompanied by diffusion of oil into the polymer. The effects of the following factors on the migration process were examined: (a) the nature of petroleum oil; (b) the nature of the phthalate plasticizer; (c) the amount of plasticizer; (d) the plasticization process; (e) the temperature; and (f) the time.