Matteo Minelli1, Marco Rocchetti2, Maria Grazia De Angelis3, Angelo Montenero2, and Ferruccio Doghieri4. (1) University of Bologna, Via Terracini 34, Bologna, Italy, (2) University of Parma, Parma, Italy, (3) Department of Chemical Engineering, University of Bologna, Via Terracini 34, Bologna, Italy, (4) Chemical Engineering, Mining and Environmental Technology, University of Bologna, viale Risorgimento 2, Bologna, Italy
The permeability and diffusivity of oxygen in films of PET coated with a thin layer of a hybrid organic/inorganic (ceramer) material have been determined at 65°C. The permeability data are collected using a closed-volume permeation apparatus and the diffusivity has been calculated with the time-lag method. The addition of coating dramatically improves the oxygen barrier properties of the substrate, the apparent permeability of the multilayer film being up to 3 orders of magnitude lower than that of pure PET. The pure coating properties are opportunely calculated by taking into account the effect of the different diffusion resistances in the various layers. The effect of ageing has also been investigated, by comparing the oxygen permeability before and after immersion in water of the films that are suspected to be degraded by water.