Anomalous sorption in poly(ethyl methacrylate)

Vapor sorption data were obtained for the ethylbenzene–poly(ethyl methacrylate) system at 120°C. Successive step-change sorption experiments carried out at two-film thicknesses indicate the presence of maxima in the sorption curves. The fractional amount of overshoot decreased as the final pressure or weight fraction of the experiment increased and as the sample thickness increased. It is proposed that the maxima in the sorption curves are caused by structural rearrangements produced by relaxation of polymer chains.