Simultaneous experimental evaluation of solubility, diffusivity, interfacial tension and specific volume of polymer/gas solutions

In this paper we present a new methodology, based on the coupling of a gravimetric method and of Axisymmetric Drop Shape Analysis (ADSA), which allows for the simultaneous measurement of solubility, diffusivity, specific volume and interfacial tension of molten polymer/gas solutions. This approach, besides supplying information on useful material properties, significantly enhances the reliability of the values of the single measured properties. In fact, the evaluation of the specific volume of molten polymer/gas solutions can be used to accurately account for the buoyancy correction to be applied in both the gravimetric sorption experiment and in the evaluation of interfacial tension. In this work, we illustrate the details of this combined technique highlighting the advantages of these simultaneous measurements and, as an example, we report the results obtained in the case of molten poly(ε-caprolactone)/carbon dioxide solutions.