Evaluating functional barriers to prevent migration of contaminants from post-consumer recycled plastic fabricated into single-layer and lamination films

A study involving the potential migration of contaminant substances from a recycled high density polyethylene (HDPE) film into a selected food simulant was carried out. Isopropanol and tetracosane, which are chemical contaminants recommended by the FDA as representatives of a polar-volatile group and a nonpolar-nonvolatile group, respectively, were selected as the chemical surrogates. For isopropanol, the diffusion coefficient in HDPE film was determined by both isostatic and quasi-isostatic permeation methods with good agreement. The partition distribution of isopropanol between HDPE film and water was also determined from a sorption experiment. For tetracosane, the diffusion coefficient was determined by monitoring the migration of tetracosane from impregnated HDPE film, which was fabricated from a tetracosane spiked HDPE resin by film extrusion, into hexane. The effectiveness of a functional barrier to prevent the migration of both compounds from a laminated film composed of a contaminated HDPE layer and a virgin HDPE layer into food was evaluated by two migration models. Modeling the migration of the two chemical surrogates from a single layer film was also carried out. A comparison of, and optimization of the respective models for estimation of migration rates was also concluded.