Polyamide/SDS-clay hybrid nanocomposite membrane application to water-ethanol mixture pervaporation separation

A polyamide/clay hybrid nanocomposite membrane was utilized in the pervaporation of aqueous ethanol mixtures. The polyamide/clay hybrid polymers were prepared by direct polycondensation of 4,4'-methylenedianiline (MDA) and 4,4'-hexafluoroisopropylidenedibenzoic acid (6FDAc) in the presence of organo-modified montmorillonite (organo-clay) in N-methyl-2-pyrrolidinone (NMP). The organo-clay (SDS-clay) was prepared using an ion-exchange reaction between the montmorillonite silicate layers and the sodium dodecyl sulfate (SDS, intercalating agent). The as-synthesized polyamide/clay hybrid membranes were characterized using wide-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM). The SDS-clay was intercalated and exfoliated into the polyamide matrix. Compared with the pure polyamide membrane, the polyamide/SDS-clay hybrid nanocomposite membrane showed improved thermal stability and mechanical properties. The glass transition temperature of polyamide/SDS-clay nanocomposite was higher than that for the pure polyamide. The SDS-clay content, feed composition and swelling effects on the pervaporation performances of aqueous ethanol mixtures through the polyamide/SDS-clay nanocomposite membranes were also investigated. (C) 2004 Elsevier B.V. All rights reserved.