Permeation of carbon dioxide through multiple linear low-density polyethylene films

We have investigated the effect of stacking on the permeation of carbon dioxide through multilayer LLDPE films. The measurements were carried out using samples made up of one, two, four, eight and 12 films, respectively, over the temperature interval of 25–85°C. The results indicate that the permeability coefficient P of carbon dioxide does not show any variation on the number of films stacked. In contrast, the time lag values increase in a non-linear way with increasing the number of films in the samples. The analysis of these results, according to gas permeation models through multilayer systems, shows that boundary effects at the interface between films are not found, on the one hand, and the experimental values determined for the time lags are in good agreement with the theoretical predictions, on the other hand.