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The FDA is concerned that recycled plastics may harbor contaminants acquired through storage abuses. There is concern that plastic containers may be used for interim storage of potentially hazardous materials. The purpose of this project was to develop a systematic assessment of the safety of recycled polymers for food contact based on migration data and mathematical models.
Diffusion, solubility and permeability data have been used to model surrogate uptake during the challenge phase of 'Points to Consider' studies and desorption during processing phases for pilot level studies. Projections have been accurate to within 5%. Models have correctly predicted the outcome of 'Points to Consider' type studies for PET and polypropylene/ethyl vinyl alcohol composites. A method of calculating diffusion has been developed which provides insights into molecular processes of volatile sorption and migration, including dual sorption and solvation mechanisms. Models have suggested possible improvements in polymer processing to enhance removal of post consumer contaminants.