Zeolite-based composite PEEK-WC membranes: Gas transport and surface properties

Mixed matrix membranes (MMMs) have been prepared by using different protocols in order to improve the affinity between NaA (LTA) zeolite and a modified polyetheretherketone (PEEK-WC). A terpenic resin has been added to the polymer-zeolite slurry for enhancing the polymer chain flexibility and, consequently, its adhesion with the crystals. Coupling agents such as gamma-aminopropyl-dieth-oxymethyl silane (APDEMS) and diethanolamine (DEA) have been used to modify the zeolite surface. The instrumental analyses showed a relative efficiency of these treatments with respect to the simple dispersion of the inorganic fillers within the polymer matrix. At high zeolite concentration (30 wt%), MMMs arc characterised by gas transport properties lower than neat polymer-based membrane. DEA-based treatment seems the more encouraging approach also taking into account that as the filler concentration decreases, the occurrence of defects at the interface becomes less significant. (C) 2008 Elsevier Inc. All rights reserved.