Semi-interpenetrating (SPN)
and interpenetrating polymer network (IPN) membranes were prepared from a mixture system of poly(4-vinylpyridine) (P4VP) and poly(glycidyl methacrylate) (PGMA) by quaternizing crosslinking of P4VP with 1,4dibromobutane (DBB) and by simultaneous crosslinking of P4VP with DBB and PGMA with tetraethylenepentamine (TEPA), respectively. The difference between SPN and IPN was demonstrated by IR, tensile strength, and dimension stability. The membrane performance in pervaporation (PV) for ethanol-water mixtures and reverse osmosis (RO) was investigated. The polymer mixture of 1 : 1 on a monomer base with 30 mol % DBB on the 4VP unit and 5.6-7.5 mol % (8-10 wt %) TEPA on the GMA unit gave an optimum membrane performance. Those crosslinked membranes were stronger than was the cellulose acetate membrane, mostly owing to the PGMA chains, and exhibited a high separation factor for the azeotropic feed in PV. IPN membranes generally showed a performance higher than that of the SPN ones. An attempt to improve the product rate was made by the addition of a water-soluble polymer to the membrane on casting. The separation factor for solubility in the membrane at the feed side dominated the overall separation factor, particularly for feeds of higher ethanol concentrations.