A new series of wholly aromatic poly(arylene ether ether ketone ketone)s
containing pendant sulfonic acid groups (SPAEEKK) were conveniently
prepared by potassium carbonate mediated nucleophilic polycondensation
reactions of inexpensive commercially available monomers:
1,3-bis(4-fluorobenzoyl)benzene (BFBB), sodium
6,7-dihydroxy-2-naphthalenesulfonate (DHNS), and 4,4'-biphenol or
hydroquinone in N-methyl-2-pyrrolidone (NMP) at 170.degree. C. FT-IR and
NMR were used to characterize the structures and the sulfonate or
sulfonic acid contents (SC) of the polymers. Flexible membrane films were
obtained by casting N,N-dimethylacetamide (DMAc) solutions of copolymers.
Membrane films in acid form were then obtained by treating the sodium
form membrane films in 2 N sulfuric acid at room temperature. Glass
transition temperatures (T.sub.gs) and decomposition temperatures
(T.sub.ds) of SPAEEKKs in both sodium and acid forms were determined.
Water uptake and swelling ratio values increased with SCs and
temperatures. The proton conductivities of acid form membrane films
increased with SC value and temperature and reached
5.6.times.10.sup.-2S/cm at 100.degree. C. for SPAEEKK-100.