Hydrophilic modification of engineering polymers

Water-soluble carboxylated polymers were synthesized from engineering polymers via the metallation of poly(oxy-1,4-phenylenesulphonyl-1,4-phenyleneoxy-1,4-phenyleneisopropylidene-1, 4-phenylene) and poly(oxy-2,6-dimethyl-1,4-phenylene) with n-butyllithium followed by reaction with carbon dioxide. Interactions between lithium sites on the polymer backbones cause the precipitation of highly metallated polymers. Precipitation of PPO occurs at approximately 15% metallation based on polymer repeat unit. Reproducibility problems are encountered with highly metallated, precipitated polymers. An ester-functional comb-type graft copolymer is synthesized via the anionic polymerization of methyl methacrylate (MMA) from metallated sites on PPO. The ester functionalities can be transesterified with hydroxy functional reagents to yield well-defined comb-type graft terpolymers. Transesterification of oligomeric polyethylene glycol onto PPO-MMA yields a comb-type graft terpolymer with nonionic hydrophiles.