Alternative fatty food simulants for polymer migration testing

Abstract

The amounts of substances migrating from plastics into foodstuffs with high fat contents are usually higher than into aqueous foodstuffs. In most cases this is due to the higher solubility of the migrating organic compounds in fat compared to water and not due to an increase in the diffusion coefficient due to interactions between the fat and plastic as is often assumed. Ethanol and aqueous ethanol mixtures can be good fatty food simulants because they interact very little with many plastics, migrants are readily soluble in them and because they are easy to work with analytically. The utilize able limits of aqueous ethanol and other low molecular weight solvents as food simulants are developed from the physical chemical background of partition coefficients and diffusion. The use of ethanol simulants is supported by experimental results for polyolefins and rigid polyvinyl chloride. Other low molecular weight solvents for other classes of polymers are suggested. The UNIFAC activity coefficient estimation method is applied to alternative fatty food simulants/polymer systems and estimations for sorption and partition coefficients are compared with experimental results.