Effect of nanoclay on the transfer properties of immanent additives in food packages

Polymer nanocomposites and specifically clay-based nanocomposites are emerging in the food packaging area and are promised to have a growing market. While the advantages of the nanoparticles on the gas barrier properties of the nanocomposites are already well-investigated and confirmed, the effect of these nanoparticles on the migration of other non-nano and potentially toxic components of the polymer packaging has still remained unclear. The present study addressed the effect of nanoclay on the migration of various additives from nanoclay/LLDPE nanocomposite packaging by determining the apparent diffusivity of these additives from the samples in contact with four different types of food simulants that distinctively exhibit hydrophilic and lipophilic characters. The results indicated that apart from the tortuosity effect that influence in a low extent the diffusivity of model migrants, the presence of nanoclays modifies the transport properties of materials as a result of their impact on other factors such as crystallinity and swelling capacity. PLS analysis on the influential geometrical and physical properties additionally revealed that the affinity between the food simulant and the polymer has the dominant effect on determining the order of apparent diffusivity as well as the effectiveness of barrier properties of nanoclays to reduce the diffusivity of additives through food packaging. Such statements suggest a benefit provided by nanoparticles incorporation in terms of the human exposure to plastic additives.