Abstract

The barrier properties of flexible films play an important role in determining the shelf life of packed foodstuffs. The mathematical models developed to describe the phenomena are based on modifications of Fick’s law in a continuous macroscopic approach. In these kinds of models the transport parameters like diffusivity or permeability are the result of the history of the process. Also, with this approach it is impossible to obtain fluid distribution at pore-level at process advance. The objective of this work is to present a model of transport of water vapour and oxygen at pore-level. The proposed model is represented by a non-hygroscopic liquid-wet porous media. 2D pore networks represent pore spaces. The process is considered under isothermal condition. To validate the model we use experimental results to chitosan films obtained in specialized literature. Pore radius is randomly assigned according to log-normal distribution function for chitosan film. Here we report at pore scale images of liquid and vapour distribution as condensation occurs during water vapour transport in polymeric films. Also we determine effective vapour and oxygen diffusivity and absolute permeability.