Non‐Fickian vapor sorption kinetics in rubbery poly(dimethyl silamethylene) and the effect of radiation‐induced crosslinking

Successive sorption runs of n‐hexane vapor in supported amorphous poly(dimethyl silamethylene) films at 25°C are presented and discussed. Deviations from Fickian sorption kinetics were observed, and they were more distinct in the as‐prepared films and in the lower n‐hexane vapor pressure runs. Polymer films, γ‐irradiated to produce various degrees of crosslinking, exhibited closer conformity to Fickian sorption kinetics and enhanced diffusivity of n‐hexane vapor. These results were consistent with the presence in the as‐prepared polymer of some labile structural order (undetectable by differential scanning calorimetry or X‐ray diffraction), which tended to be eliminated by radiation‐induced crosslinking or strong swelling.