Polymer/layered silicate clay nanocomposites have attracted a great deal of interest in both industry and academia. The starting point was the rst successful revelation of the intercalation/exfoliation concept by Toyota researchers in Japan in the early 1990s on a nylon/clay combination [1-5]. The main reasons behind the intense research activity in this eld are the enhanced properties of nanocomposites compared to the pure polymers and the conventional ber-and ller-reinforced composites. They exhibit a large increase in elasticity modulus, strength [6-8], and heat resistance [9], in addition to a substantial decrease in gas permeability [10-12] and ammability [12-14]. Polymer nanocomposites are very valuable when used in coating, structural, and packaging materials in a wide range of applications. It has to be emphasized that these properties require full exfoliation of the clay into very individual platelets, uniformly distributed throughout the nanocomposite volume.