Modelling of migration from multilayers and functional barriers: estimation of parameters
Résumé
Functional barriers are parts of multilayer packaging materials, deemed to protect the food from migration of a broad range of contaminants e.g. associated to reused packages. Often, neither the presence nor the identity of the contaminants is known, so that safety assessment of the materials has to rely on predictive tools. Several complementary freeware described here allow to model diffusion in multi-layer films. These tools require the input of parameters which are not easy to determine or to predict. Previous works have focused on prediction of diffusion coefficients at temperatures of storage of packaging in contact with food. However many other kinetic and thermodynamic parameters are needed to describe transport properties during processing of the material at high temperature and shelf life of the materials. All parameters needed for the calculations are discussed. In order to propose default values, the approach consists in (i) reviewing available literature data (ii) running experiments on polypropylene, polyethylene and poly(ethylene vinyl alcohol) in typical conditions (separately diffusion during processing and migration) (iii) simulating numerically sets of typical situations. Several freeware are proposed to simulate migration from multilayers and functional barriers using the default parameters.
Origine : Fichiers produits par l'(les) auteur(s)
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