Performance of SPEEK based polymer–nanoclay inorganic membrane for DMFC

Sulfonated poly (ether ether ketone) (SPEEK) membrane with degree of sulfonation (DS) of 63% was modified by adding various amounts of Cloisite15A® clay. The effect of clay loading on the physical properties of SPEEK nanocomposite membranes was investigated. SPEEK mixed with 2.5 wt.% of Cloisite15A® (SP63/2.5Cl) has been identified as the best composite formulation in this study. Subsequently, various amounts of 2,4,6-triaminopyrimidine (TAP) were further incorporated into SP63/2.5Cl formulation. The effect of TAP incorporation on the physical and performance properties of the membranes was studied. Nanometer scale distribution of Cloisite15A® in the SPEEK polymer matrix has been achieved by the assistance of TAP, as observed by the field emission scanning electron microscopy (FESEM). A complete exfoliated nanocomposite structure of SP63/2.5Cl/5.0TAP was confirmed by X-ray diffraction (XRD). The increase of Cloisite15A® content in the SPEEK membrane has dramatically improved the swelling behavior and barrier properties towards methanol. The SP63/2.5Cl/5.0TAP polymer–clay nanocomposite membrane served as a promising alternative proton exchange membrane (PEM) for DMFC applications with superior DMFC performance compared to commercial Nafion®112.

► SPEEK intercalated with Cloisite15A® in the presence of various weight loading of TAP was successfully prepared.
► The incorporation of appropriate amount of TAP allowed homogenous dispersion of Cloisite15A® in SPEEK.
► The swelling and mechanical stability was remarkably improved by Cloisite15A® and TAP incorporation.
► The addition of Cloisite15A® and TAP is an effective approach to improve the performance of SPEEK for DMFC.