Nano composite membranes of branched sulfonated poly(ether ketone sulfone) and SiO_2 for fuel cell application

摘要

Branched sulfonated poly(ether ketone sulfone) copolymer was prepared from 1,1,1-tris(4-hydroxyphenyl) ethane, 4,4-difluorophenylsulfone, 3,3'-disodiumsulfonylbenzophenone (40 mol% of bisphenol A) and bisphenol A by polycondensation with the elimination of water in toluene and NMP at 160□ in the presence of anhydrous potassium carbonate. Composite membranes were successfully cast from the control of organic polymer with SiO_2 4-10 wt% of polymer in DMSO. The films were converted from the salt to acid forms with dilute hydrochloric acid. Organic-inorganic composite membranes for operation in polymer electrolyte membrane fuel cells (PEMFCs) were characterized and cell-tested. The physico-chemical properties of all membranes were investigated their thermal properties, water uptake, DSC and thermogravimetric analyzer (TGA). Branched copolymer and nano composite membranes exhibit proton conductivities from 1.7×10~(-3) to 8.3×10~(-3) S/cm~2, water uptake from 22 to 26%, IEC from 1.28 to 1.46 meq/g and methanol diffusion coefficients from 1.2×10_(-7) to 1.7~10~(-7)cm~2/S.