For example, one of the adjacent layers may comprise non-polar polyethylene homopolymer or copolymer while the other adjacent layer comprises at least one material selected from the group consisting of polyamide, copolyamide, polyester, copolyester such as polyethylene terephthalate, polar polyethylene copolymers such as ethylene/vinyl alcohol, polycarbonate, polymethylpentene, polyvinylidene chlo