Fluorinated poly(arylene ether ketone) containing pendent hexasulfophenyl for proton exchange membrane

A series of novel poly(arylene ether ketone)s with hexasulfophenyl pendents (6F-PAEK-SPx) were synthesized by polycondensation reaction of commercial 4,4'-(hexafluoroisopropylidene)diphenol (6FBPA), 4,4'-difluorobenzophenone and a new difluoride monomer, and followed by a post sullonation modification with chlorosulfonic acid. Controlling of substituent positions and the degree of sullonation were realized using quantities of the new difluoride monomer. The structure of 6F-PAEK-SPx was confirmed by H-1 NMR and FT-IR instrument. The tough, flexible and transparent films of 6F-PAEK-SPx were obtained by solution casting. Those membranes with desired IEC values showed excellent thermal stability and mechanical properties. The membranes of 6F-PAEK-SPx copolymers containing hydrophobic main chain and hydrophilic micro-clustered pendent exhibited high proton conductivity and lower dimensional change value. The proton conductivity of 6F-PAEK-5P22 with the lEC of 1.77 meq/g was higher than that of Nafion 117 from 20 degrees C to 100 degrees C. The excellent properties of the membranes were attributed to the good hydrophobic/hydrophilic morphology of the membranes. The novel 6F-PAEK-SP copolymers combining the advantages of the well defined proton transport channels and enhanced physical properties will be the potential alternative materials to Nafion for PEMFC. (C) 2015 Elsevier B.V. All rights reserved.