Predicting the permeability and tensile properties of multilayer films from the properties of the individual component layers

Abstract

We have fabricated typical three-layer films (A/B/C multilayer structures), comprising polyamide-6 (PA-6), low-density polyethylene (LDPE), and adhesive (low-density ethylene grafted with maleic anhydride, LDPE-g-MAH), by a coextrusion blown-film process using various compositions of the three layers. With the goal of predicting the permeability and tensile properties of the three-layer films, we examined model predictions and the properties of the individual component layers to provide an economical and efficient pathway to designing desired multilayer structures. We used the series model for predicting permeability; a good agreement exists between experimental data and this model for predicting both gas and water vapor permeabilities of three-layer films having various contents of PA-6. By using the additive rule model, we can also predict the tensile properties, including the true yield stress, strain hardening parameter, and tensile modulus of the three-layer film from those of the individual component layers, with particularly high accuracy in the true stress-strain relationship.