Characterization of solvent-filler-poly(dimethylsiloxane) membranes by Differential Scanning Calorimetry

The properties of three polydimethylsiloxane (PDMS) membranes filled with crystalline zeolites and with amorphous SiO2 respectively, before and after sorption of organic solvents were studied by DSC. The PDMS crystallinity of the membranes with sorbed solvents is affected by both the solvent and the filler natures. For SiO2-filled membrane, the PDMS crystallinity increases first due to the weakening of the physical crosslinks by the solvent. In the case of zeolite fillers, the PDMS crystallinity decreases first with the increase in the solvent content due to a decrease in the zeolite-induced crystallization effect by the solvent adsorption on zeolites. At high solvent contents, the solvent influence on the PDMS crystallite prevails. A medium solvent (ethyl acetate) induces the polymer crystallization, while a good solvent (cyclohexane) disrupts PDMS crystallites.