Functional barrier performance of a polyamide-6 membrane towards n-Alkanes and 1-Alcohols
Polymeric barrier membranes are widely used in the food packaging area. So-called functional barriers prevent the packed food from contamination of permeants from the environment or from other packaging components. Aim of the study was to determine barrier properties of non-polar n-alkanes (n-pentane up to n-tetradecane) and polar 1-alcohols (1-propanol to 1-octanol) of a 12 µm biaxially oriented PA6 film at temperatures between 70°C and 100°C. From the experimentally determined lag times, the diffusion coefficients DP as well as the partition coefficients K of the investigated permeants were calculated. From the correlation between the molecular volume V and the diffusion coefficients DP, the lag times for lower temperatures can be predicted for temperatures between 20°C and 70°C. In conclusion, the investigated 12 µm PA6 film is a sufficient barrier towards organic compounds. The permeation of substances with molecular volumes above 200 Å3 is negligible for a shelf life of three years and temperatures below of 60°C. These storage conditions are sufficient for nearly all kinds of food packaging applications.