Novel polysiloxaneimide/polyetherimide/non-woven fabric composite membranes for organophilic pervaporation

In this study, a novel composite membrane using polysiloxaneimide (PSI) as a selective layer was developed for hydrophobic pervaporation. The PSI was synthesized from 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA) and amino-modified siloxane (dual-end type). The physiochemical characterization of the PSI using FTIR, NMR and XRD confirmed the success of the synthesis. A non-woven fabric layer covered by a crosslinked porous polyetherimide (PEI) layer was used as a support for the composite membrane. The PSI layer was formed by non-solvent induced phase inversion. The effects of temperature in pervaporation, as well as the preparation conditions in terms of the support layer structure, PSI dopant solution composition and post treatment on the pervaporation performance of the composite membranes were investigated. The pervaporation test for recovering ethanol from its aqueous solution (5 wt%) at 60 °C showed that the highest separation factor obtained with the composite membrane was ~3, and the corresponding flux was ~0.5 kg/m2 h.