Abstract: A multi-layer composite has at least one elastomer layer and at least one barrier layer. In various embodiments, the composite contains at least two elastomer layers alternating with at least two barrier layers. In other embodiments, the composite comprises at least ten alternating barrier and elastomer layers. The barrier layer is made of an amorphous polymer, and is provided in the form of a film. Preferably, the amorphous polymer film has a gas transmittance rate (GTR) of less than 40 cc·mil/m2·day·atm, preferably less than 20 cc·mil/m2·day·atm, measured as nitrogen transmittance at 0% relative humidity at 23° C.