Hye Seok Park, Dong Wan Seo, Seung Woo Choi, Young Gi Jeong, Ju Ho Lee, Dong Il Kim and Whan-Gi Kim
Branched sulfonated poly(ether ketone sulfone)s (Br-SPEKS) were prepared with bisphenol A, bis(4-fluorophenyl)sulfone, 3,3′-disodiumsulfonyl-4,4′-difluorobenzophenone, and THPE (1,1,1-tris-p-hydroxyphenylethane), respectively using potassium carbonate in NMP (N-methylpyrrolidinone). THPE, as a branching agent, was used with 0.4 mol % of bisphenol A to synthesize branched copolymers. Copolymers containing 10–50 mol % disulfonated units were cast from dimethylsulfoxide solutions to form films. A series of copolymers were studied by FT-IR, 1H-NMR spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The synthesized Br-SPEKS and SPEKS membranes exhibit conductivities (25 °C) from 1.04 × 10−3 to 4.32 × 10−3 S/cm, water swell from 20.18 to 62.35%, IEC from 0.24 to 0.83 meq/g and methanol diffusion coefficients from 3.2 × 10−7 to 4.7 × 10−7 cm2/S at 25 °C.