Polyaromatic ethers polyethers

Sulfonation is very useful chemical modification of polymer, as it induces high polarity in the polymer changing its chemical as well as physical properties. Sulfonated polymers are also important precursors for ionomer formation [75]. There are reports of sulfonation of ethylene-propylene diene terpolymer (EPDM) [76, 77], polyarylene-ether-sulfone [78], polyaromatic ether ketone [79], polyether ether ketone (PEEK) [80], styrene-ethylene-butylene-styrene block copolymer, (SEBS) [81]. Poly [bis(3-methyl phenoxy) phosphozene] [82], Sulfonated polymers show a distinct peak at 1176 cm"1 due to stretching vibration of 0=S=0 in the -S03H group. Another peak appears at 881 cm 1 due to stretching vibration of S-OH bond. However, the position of different vibrational bands due to sulfonation depends on the nature of the cations as well as types of solvents [75, 76]. 

The reaction of the cationic polyether, 196, with sodium cyanide led to the isolation of the neutral adduct, 197.254 Demetallation of these adducts via chemical oxidation with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) gave the nitrile functionalized polyaromatic ethers 198 (Scheme 2.52). 

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