SORPTION ISOTHERMS OF ALCOHOLS IN ZEOLITE-FILLED SILICONE-RUBBER AND IN PVA-COMPOSITE MEMBRANES

Results are reported of dynamic vapour-sorption experiments of various alcohols in a zeolite-filled silicone rubber membrane and in a poly(vinyl alcohol) (PVA)-composite membrane. In order to determine the influence of the filler on sorption behaviour, sorption experiments also were performed with a silicone rubber membrane without filler and with zeolite ZSM-5 as filler. The results show that adsorption by the zeolite contributes much more to the total sorption than the absorption by the silicone rubber. The PVA-composite membrane investigated consists of poly(vinyl alcohol) (PVA) and of polyacryl nitrile (PAN) as porous support. Vapour-sorption data of H2O and alcohols in the PVA-composite membrane and in its PVA- and PAN-layers are presented and discussed in order to find out to which extent the sorption characteristics of the selective layer are affected by the support.