Poly(aryl ether ketone)s with bromomethyl groups: Synthesis and quaternary amination

A series of bromomethylated poly(arylene ether ketone)s (PAEKs) with different contents of bromine tethered to the benzyl groups were successfully synthesized and characterized in this work. For this purpose, poly(arylene ether ketone) with 3,3′,5,5′-tetramethyl-4,4′-dihydroxybipheny moiety (PAEK-TM) was prepared by the aromatic nucleophilic polycondensation, and then the PAEK-TM has benzylic methyl groups that were converted to bromomethyl groups by a radical reaction using N-bromosuccinimide. Then, the bromomethylbenzyl groups in the membrane was converted to quaternary ammonium moieties in TMPAEK-NOH. ¹H-NMR measurements were used to characterize and confirm the structures of the resulting PAEK-x-BrTM and TMPAEK-NBr derivatives (x refers to the molar percentage of bromine introduced per repeating units). TGA analysis showed that PAEK-x-BrTM exhibited a very low-decomposition temperature at about 200°C corresponding to the CBr bond cleavage. The hydroxide conductivity of TMPAEK-NOH membrane was 8 mS cm^-1 at room temperature, while the water uptake of TMPAEK-NOH membrane was 22.3% at 20°C and 32.6% at 60°C.