Abstract: Nanocomposites prepared by co-intercalation of an onium ion and MXD6 nylon between the planar layers of a nanoclay. The spacing of adjacent nanoclay layers is expanded at least 3 Å, and preferrably 15-20 Å. The intercalation of the MXD6 nylon polymer then increases the spacing of adjacent layers an additional distance preferably about 25 Å to about 30 Å, creating a nanocomposite with enhanced gas barrier properties.