Kinetics of diffusion of a pollutant from a recycled polymer through a functional barrier: Recycling plastics for food packaging

Recycled polymers containing a pollutant can be used for food packaging if the food is protected by a functional barrier made of virgin polymer. The mathematical treatment of the diffusion of pollutant through the packaging is established when the diffusivity is constant and when there is no transfer through the packaging-food interface. A functional barrier not only reduces but also delays migration during a lag phase. An increase in the relative thickness of the functional barrier dramatically increases its efficiency. Practical examples are presented. The difficulties of control of migration through functional barriers are pointed out. (C) 1997 John Wiley & Sons, Inc.