INCORPORATION OF HYDROPHOBIC POROUS FILLERS IN PDMS MEMBRANES FOR USEIN PERVAPORATION

Three types of hydrophobic porous fillers (carbon blacks, in situ meth ylated silicas, and silylated silicas) were incorporated in PDMS (poly dimethylsiloxane) membranes in order to find out under which condition s these filled membranes were advantageous for pervaporation of aqueou s solutions, The properties of these fillers were changed systematical ly in order to maximize fluxes and selectivities in the pervaporation of aqueous ethanol, tertiary butyl alcohol, or aroma solutions. Ma-ny fillers were able to realize an increased membrane selectivity, but no ne of them could combine this with an increased organic flux. In ?his respect, silicas silylated with TMCS (trimethylchlorosilane) were foun d to be the best fillers. The filler addition was most beneficial when applying feed mixtures that induced low swelling in the membrane.