MIGRATION OF STYRENE MONOMER FROM POLYSTYRENE PACKAGING MATERIALS INTO FOOD SIMULANTS

Migration studies of residual styrene from Impact Polystyrene cups into soybean oil were carried out at several temperatures. Experimental migration curves were compared to theoretical ones calculated from diffusion-type equations; the former showed higher (by approximately 20%) migration rates and equilibrium styrene concentrations in the oil. Even though the residual styrene was in most cases below 0.1% (far below the levels allowed by the FDA), significant migration occurred, and the resulting styrene concentrations in the oil exceeded the previously determined organoleptic threshold by more than an order of magnitude. The diffusion coefficient of styrene in polystyrene was found to decrease and the partition coefficient to increase with the decrease of residual styrene indicating an increase in monomer-polymer interaction.