Barrier properties of flake-filled membranes: Review and numerical evaluation

Flake-filled polymer membranes belong to an emerging class of composite materials that show promise as barrier materials in many industrial applications. Though the barrier property enhancement in flake-filled membranes is well known, its dependence on microstructural factors, such as flake spatial distribution, size dispersion, and orientation is not well understood. This study presents a micromechanics-based, direct numerical approach to predicting the barrier improvement factors of flake-filled membranes. Numerical calculations are conducted in two-dimensions for composite membranes containing aligned, impermeable flakes, using the fast multipole-accelerated boundary element method. Theoretical models which predict the barrier properties of flake-filled membranes are reviewed and their predictions compared with the boundary element calculations.