Migration of styrene from plastic packaging based on polystyrene into food simulants

Migration of potentially toxic substances from plastic packaging materials is very important in the food industry since it determines the suitability of polymers when used in food packaging. In this work, results are presented on the migration of styrene monomer from plastic packaging based on either rigid or foamed polystyrene. Water, ethanol/water solution and isooctane (resembling oil) were considered as food simulants. Experiments were carried out at various temperatures and migration was tested from 30 min to 30 days. Measurements were carried out using gas chromatography with external calibration and styrene standard solutions. No styrene was measured in water, except at high temperatures and long time periods, while the amount in ethanol/water was always grater than that in isooctane. Finally, the styrene diffusion coefficients for all the various experimental conditions were estimated using a rigorous model based on the Fick diffusion equation and the partitioning of the monomer between the two phases and consequently the activation energy of the migration process was evaluated. Copyright (C) 2011 Society of Chemical Industry