Résumé
Predicting barrier properties of multilayer materials is essential for designing effective food packaging. Although resistance-based models are commonly used, their applicability to complex structures, such as polymer-coated paper/cardboard, remains underexplored. This study investigates the predictive ability of these models for multilayer systems composed of cellulosic substrates laminated with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Four model materials were designed to cover a wide span of barrier properties. PHBV lamination significantly improved barrier properties (up to a factor of 105), primarily through the formation of an impregnated layer rather than a continuous film. Spatial heterogeneities within the samples were integrated into the modeling approaches. Different structural assumptions were considered. None of the models accurately predicted the barrier properties of all PHBV-laminated samples, highlighting the influence of additional factors such as interfacial adhesion, polymer crystallinity, and local defects. This work proposes, for the first time, an experimental estimation of the impregnated layer's permeability (from 10-15 to 10-13 mol.m.m-2. s-1.Pa-1 for oxygen permeability to 10-15-10-12 mol.m.m-2.s-1.Pa-1 for water vapor permeability). These findings indicate that a free polymer layer is not strictly required to achieve substantial barrier enhancement and underscore the central role of the impregnated layer in mass transfer, reinforcing the need to refine existing predictive models.