The sorption of limonene/ethyl acetate binary vapour mixtures by a biaxially oriented polypropylene film

The sorption of ethyl acetate and limonene as individual sorbates and in binary vapour mixtures by an oriented polypropylene was determined by two independent methods, namely by gravimetric and thermal stripping/thermal desorption procedures. The two methods showed excellent agreement. The solubility coefficients for the two species were found to be independent of sorbate concentration within the ranges studied, indicating that sorption followed Henry's law. Calculated and experimentally obtained sorption profile curves agreed well for both ethyl acetate and limonene at low vapour activities. At a limonene vapour activity of 0.29 there was a lack of agreement between experimental and calculated results. This was attributed to the onset of non‐Fickian relaxation effects occurring within the polymer matrix at this limonene concentration. The results of sorption studies involving binary vapour mixtures indicated that at the concentration levels evaluated, the co‐permeant did not effect the sorption characteristics of the other sorbate.