On the chloromethylation of polyetherethersulphone/polyethersulphone copolymers. The use of triflic acid as catalyst

Polyetherethersulphone-polyethersulphone (PEES-PES) copolymers have been chloromethylated using chloromethyl butyl and octyl ethers as the source of the chloromethyl group and trifluoromethylsulphonic acid (triflic acid) as both cosolvent and acidic catalyst. This combination is successful, in contrast to other systems which failed to produce chloromethylated, uncrosslinked materials. Nuclear magnetic resonance studies indicate that the chloromethylation proceeds exclusively on the hydroquinone residue of the PEES unit.