Effect of Clay Modification on the Structure and Properties of Sulfonated Poly(ether ether ketone)/Clay Nanocomposites

Sulfonated poly(ether ether ketone) (SPEEK)/clay hybrid membranes were prepared using three types of commercially available clays, the sodium montmorillonite (IC), hydrophobic organo-clay with long alkyl chains (OC), and organo-clay with carboxylic acid end groups (HC). It was found that the SPEEK/HC hybrid membranes achieved the best clay dispersion, with the exfoliation of the clay nano-platelets when the filler loading was < 10 wt%. The incorporation of the carboxylic acid groups in clay layers also improved the connectivity between the ionic clusters in the membrane, resulting in higher proton conductivity without compromising the dimensional stability of membranes. The selectivity higher than the pristine SPEEK membranes was obtained for the SPEEK/HC hybrid membranes at low filler loading (<10 wt%), with higher proton conductivity and similar methanol permeability. (C) 2015 Society of Plastics Engineers