Gas Diffusion in Polystyrene Foam

A simple multiscale model was developed and used to predict gas diffusivities through expanded polystyrene foam at near standard temperature and pressure (STP) conditions. The technique involves measuring gas diffusivities at various length scales then combining them using an electrical analogy for parallel resistances to construct an effective property. A commonly used experimental technique, the continuous flow method, was used to obtain diffusivity data for argon through polystyrene films and foams. While a simple Fickian mathematical model was able to predict diffusivities through films, a “coarse” multiscale model that accounts for the morphological features was required for the foam.