REACTIONS OF EPOXIDE MONOMERS IN FOOD SIMULANTS USED TO TEST PLASTICSFOR MIGRATION

The reactions of four epoxides used as monomers for food contact plast ics were studied in the food simulants distilled water, 15% aqueous et hanol, 3% aqueous acetic acid and olive oil. Loss of the parent substa nce and formation of products was monitored to establish the transform ation products to be expected in each simulant following migration tes ting of plastics. Each epoxide was stable in olive oil but suffered ex tensive loss in the three aqueous simulants. Reaction half-lives were from < 1 to 10 h in aqueous acetic acid, 25-63 h in distilled water, a nd 33-87 h in aqueous ethanol simulant. Hydrolysis to the diol was the main reaction pathway. Epoxide ring opening in aqueous ethanol simula nt gave the diol and also the diol monoethyl ether. It is concluded th at, for aqueous simulants and by implication for most foods, testing p lastics against specific migration limits for epoxides is not likely t o give reliable results due to their reactivity. The present BC mode o f control for these reactive monomers, via compositional limits in foo d contact plastics, is more practical since the hydrolysis products ar e less toxic than the parent epoxide.