Migrability of PVC plasticizers

The ability of different PVC plasticizers to migrate towards a polymer in contact with flexible PVC has been investigated. A procedure based on the monitoring of the plasticizer concentration by infrared spectroscopy has been employed. The mathematical model applied to experimental data has permitted the calculation of average diffusion coefficients and, hence, a comparison among the plasticizers studied (citrates, phthalates and adipates), independent of the geometry of the system employed. Under the test conditions and the probe polymer employed, phthalates seem to be the plasticizers with the lower migration, in contrast to adipates that give the highest migration levels.