@article{de angelis_sarti_2008, title={Solubility and diffusivity of gases in mixed matrix membranes containing hydrophobic fumed silica: Correlations and predictions based on the NELF model}, volume={47}, ISSN={["0888-5885"]}, DOI={10.1021/ie0714910}, abstractNote={The addition of fumed silica particles to glassy polymers such as PTMSP and Teflon AF 2400 results in an enhancement of gas diffusivity and permeability that is not captured by traditional models for composites because both volume and gas solubility of the composite material are underestimated by the additive rule based on pure component properties. Such effects have been attributed to the creation of additional free volume due to the insertion of filler in the polymeric matrix. In this work, we use the NELF model to relate gas solubility in the composite material to the variations induced by the addition of filler on polymer density and swellability. From these values, the fractional free volume (FFV) increase produced in the polymeric phase by filler incorporation may be evaluated and, in turn, also the diffusivity in the composite material can be calculated as a function of filler content on the basis of its relation to FFV. The gas diffusivity data for n-C4H10 in AF 2400 and AF 2400-based mixed matric...}, number={15}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={De Angelis, Maria Grazia and Sarti, Giulio C.}, year={2008}, month={Aug}, pages={5214–5226} }
 @article{ferrari_piccinini_baschetti_doghieri_sarti_2008, title={Solvent-induced stresses during sorption in glassy polycarbonate: Experimental analysis and model simulation for a novel bending cantilever apparatus}, volume={47}, ISSN={["0888-5885"]}, DOI={10.1021/ie071084o}, abstractNote={A new experimental apparatus has been set up to analyze the polymer dilation as well as the stress profile induced by vapor sorption in constrained films. The device couples the bending cantilever technique with a new digital micrometer, which allows one to measure both deflection and polymer swelling at the same time. The apparatus has been applied to study the effects of acetonitrile mass uptake in polycarbonate at 40 °C, obtaining the time evolution of swelling and of cantilever deflection during integral sorption tests, in the activity range from 0 up to 0.35. A simulation model is also proposed, which couples Fick's law for diffusion to the study of strain and stress distributions in the cantilever; the mechanical problem has been formulated following the classical laminate theory. The relevant values of the material properties entering the model, such as solubility, diffusivity, and penetrant induced dilation, have all been determined through separate independent measurements, and the results obtain...}, number={4}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Ferrari, Maria-Chiara and Piccinini, Enrico and Baschetti, Marco Giacinti and Doghieri, Ferruccio and Sarti, Giulio C.}, year={2008}, month={Feb}, pages={1071–1080} }