Reconciliation of pH, conductivity, total organic carbon with carboxylic acids detected by ion chromatography in solution after contact with multilayer films after γ-irradiation.

The impact of γ-irradiation on polymers in multilayer films was studied by means of the study of the diffusion and release (spontaneous migration of the molecules from the container into the product) of chemical species in aqueous solution. A series of different measurements have been performed: pH, conductivity, total organic carbon (TOC) and ion chromatography (IC). Their evolution according to γ-irradiation dose was studied. More several rinsings made over several months allowed to quantify well the impact of the irradiation on these polymers. The samples are irradiated at several γ-doses, up to 270 kGy, and compared with a non-irradiated sample used as reference. It shows that quantity of generated carboxylic acids depends on the film material (PE/EVOH/PE and EVA/EVOH/EVA) and increases with γ-dose.