Modeling Gas Barrier Property Improvements in Polymer-Clay Nano-Composites

Polymer-clay nanocomposites (PCNC) offer better properties at very low volume fraction of the nano-filler compared to conventional polymer composites, thus minimizing the effect on other favored properties of the polymer. The mechanism by which clay platelets, which have thicknesses of a few nanometers in size compared with several hundred nanometers in the other two dimensions, introduce mechanical and other properties improvement can be attributed to their high efficiency in introducing a discontinuity to flows through the bulk matrix polymer material. The extent of this improvement depends on the success of intercalation or separation of the clay platelets through the bulk matrix. This paper contains a general overview of polymer-clay nano-composites in terms of properties and processing. The improvements in gas barrier properties are discussed in detail; and a model to represent the effect of introduction of nano-fillers on the permeability is proposed. The model builds on previous models to explain the improvements in the gas barrier properties due to the presence of clay nano-particles and by assuming a proper distribution of these particles.