Determination of the diffusivity of n ‐pentane in polystyrene bead foam

The amount of residual n ‐pentane in expandable polystyrene bead foam (PSBF) has an effect on the strength and dimensional stability of the foam. Data were needed to determine how fast the residual n ‐pentane could be removed to enhance the properties of PSBF. An experiment was designed to determine the diffusivity of n ‐pentane through PSBF at various temperatures. Mathematical models based on the appropriate diffusion differential equations were then used to predict n ‐pentane concentrations in in cylinders of PSBF. The diffusivity of n ‐pentane through PSBF was found to have a magnitude of 1×10 ‐8 to 1×10 −6 cm 2 /sec and to vary with temperature, foam density, n ‐pentane concentration, and foam structure.