A Finite Element Analysis of the Influence of Morphology on Barrier Properties of Polymer-Clay Nanocomposites

D. L. Statler Jr., and R. K. Gupta
Department of Chemical Engineering, West Virginia University, Morgantown, WV, USA

Nanocomposites, formed by dispersing a few weight-percent of nanometer-thick platelets of organically-coated montmorillonite clay in a variety of polymers, are being used in food packaging applications. The clay platelets reduce the diffusion coefficient of gases, such as carbon dioxide and water vapor, and prolong the shelf-life of packaged foods and carbonated beverages.

Here we use the COMSOL software to determine the reduction in diffusivity. Computations show that, at low filler concentrations, analytical theories over-predict improvement in barrier properties, but good agreement is obtained when the nanofiller concentration or the morphology is such that platelet-platelet overlap occurs.

By examining the influence of filler dimensions, filler arrangement and filler amount, it should be possible to design nanocomposites having desired diffusion properties.