Diffusivity of Multicomponent Gas Mixtures in Polyethylene

Abstract A study of the multicomponent diffusion of important processes gases in linear low density polyethylene is presented. It is demonstrated that, much like in the case of multicomponent solubilities, one cannot use pure component diffusivities to predict mass transfer rates in multicomponent systems. It is postulated that interaction between the penetrant species and the polymer modifies the free volume in a concentration‐dependent manner, so it is necessary to consider the gas phase composition when calculating realistic diffusion coefficients. In addition, describing the particle morphology as an assembly of normally distributed characteristic length scales is proposed. This allows one to better fit the experimental data, and is a coherent description of experimentally observed particle morphology.