Name : Mohamed Abdellatif Title : Poly ( arlyene ether ) s with Truly Pendant Benzene Sulfonic Acid Groups

A series of new sulfonated poly(arylene ether)s containing one sulfonic acid group, located on a pendant phenyl sulfonyl moiety, at every repeat unit was synthesized using 3-sulfonated-3’, 5’-difluorophenyl Sulfone, 4, and a variety of bisphenols. A conventional nucleophilic aromatic substitution (NAS) was utilized for the homopolymerization and copolymerization reactions. Polymerization reactions of 4 in NMP at 180 oC provided the corresponding linear sulfonated poly(arylene ether)s, sPAEs, with number average molecular weight, Mn, ranging from 10,000 to 38,000 Daltons. All of the polymers were characterized by 1H and 13C NMR spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The Tg values ranged from 264 oC to 296 oC for the salt form and 183 oC to 240 oC for the acid form. The Td5% values ranged from 311 oC to 472 oC for the salt form and 307 oC to 367 oC for the acid form. All of the samples possessed excellent thermal stability. Furthermore, higher accessibility of the sulfonic acid groups was evident by observing increased solubility in hot water, which is presumed to construct a more efficient conductive pass way, thus increasing the proton conductivity of the newly developed systems. The polymer samples also formed tough peelable films when DMSO solutions were slowly evaporated on a glass slide. These new sulfonated polymers possess good properties and are excellent candidates for proton exchange membrane in fuel cell applications.