Diffusion in Glassy Polymers. II. Effects of Polymer-penetrant Interaction ; Diffusion of Ethyl Methyl Ketone in Atactic Polystyrene

The successive differential absorptions for the A–PS-ethyl methyl ketone system change with the initial concentration according to the same scheme as that presented previously as typical systems of amorphous polymer-organic vapor; that is, sigmoid type →pseudo-Fickian type → two-stage type → pseudo-Fickian type → Fickian type The last transition, from pseudo-Fickian to Fickian types, for ethyl methyl ketone occurs at lower concentration than that for benzene. The second stage portion of the two-stage process shifts rapidly to the short time regions as the initial concentration of each step increases. The rate of this shift depends upon initial concentration in nearly the same manner as in the A–PS-benzene system. The general features of integral absorptions for the present system are very similar to those for benzene system, irrespective of the difference in the penetrant-polymer interaction between the two systems. The dependence of absorption rate upon ΔC is also similar in general character to that for benzene system.