(163ab) Gas Barrier Properties of Polymeric Films with Hybrid Organic/Inorganic Coatings

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.