Preparation and characterization of proton exchange membrane based on poly(ether ether ketone)

Sulfonated poly(ether ether ketone) (S-PEEK)/poly(ether imide) (PEI) blend membranes were prepared using a solvent casting method. Hydrophobic poly(ether ether ketone) (PEEK) was modified by sulfonation reaction in which –SO3H groups is substituted in the aromatic rings. The commercial membrane should have good proton conductivity, high water uptake, and good thermal- mechanical stability, low fuel permeability and ultimately have lower cost. At high sulfonation degrees, water uptake raises that due to increasing proton conductivity, but the mechanical stability decreases. For enhancing the mechanical strength, the synthesized S-PEEK was blended with poly(ether imide) (PEI). Crosslinking between S-PEEK and PEI could improve the mechanical stability and flexibility but the water uptake would decrease. By introduction of 2 wt.% of PEI into the S-PEEK, the proton conductivity reached to 21.05 mS cm-1 at ambient temperature and R.H.=100%. Comparing with the proton conductivity of Nafion® 117 at the same condition (53 mS cm-1) it was observed that S-PEEK/PEI blend membrane could be promising for fuel cell applications.

Preparation and characterization of proton exchange membrane based on poly(ether ether ketone) Keywords:

S-PEEK , PEI , Proton Conductivity , Water Uptake , Acid-base interaction , Fuel cell