Solvent and acidification method effects in the performance of new sulfonated copolyimides membranes in PEM-fuel cells

International audienceNew sequenced sulfonated naphthalenic polyimides were synthesized contg. a flexible arom.-aliph. diamine. The obtained membranes present the advantage of being sol. in N-Me pyrrolidone (NMP) which is a less toxic solvent than the previously used m-cresol. The authors report on the solvent and acidification method effects on the properties of the membranes such as d., water uptake, proton cond. as well as on the performance of these membranes in fuel cell operation. The membranes prepd. from NMP soln. and acidified with ion-exchange resins give the best results. They have good mech. properties as well as high ionic cond. (14.4 x 10-2 S cm-1 at 80°C and good performances as proton exchange membrane (PEM) in fuel cell at 70°