Abstract
Migration of acrylonitrile monomer from styrene-acrylonitrile copolymer of food container into the five kinds of food simulants was studied. It reveals that migration process is made up by two kinds of diffusion steps. The initial step is believed to be the migration process from the non-plasticized polymer and the second step from the solvent-plasticized polymer. These migration processes were affected by the concentration of ethanol and by annealing at the temperature just below its glass transition temperature, e. g. 80°C. The diffusion coefficient, which was calculated from the Fickian equation, increased linearly with increasing the concentration of ethanol. The swelling capacity of the copolymer with the solvent was reduced by annealing. The diffusion coefficient of the annealed specimen at the initial step became one-half of that of the original one by annealing at 80°C for 65 hrs.
