PREPARATION OF TELECHELICS BY OXIDATIVE COUPLING COPOLYMERIZATION OF 2,6-DIMETHYLPHENOL WITH TETRAMETHYL BISPHENOL-A CATALYZED BY COPPER(II) COMPLEXES OF N-METHYLIMIDAZOLE

A series of copolymerizations of 2,6-dimethylphenol (DMP) with 2,2-di(4-hydroxy-3,5-dimethylphenyl)-propane (tetramethyl bisphenol-A, TMBPA) catalysed by N-methylimidazole Cu(II) complexes in toluene/methanol (12/3 v/v) was performed with TMBPA/Cu = 1. The main product alpha-omega-bis(2,6-dimethylphenol)-poly(2,6-dimethyl-1,4-phenylene oxide) (PPO-2OH) was characterized by H-1 nuclear magnetic resonance spectroscopy and gel permeation chromatography. It consisted of PPO-type telechelics carrying two hydroxyl end groups with M(n)BAR in the range of 3400-5000 g mol-1 and M(w)BAR/M(n)BAR ratios of approximately 1.5. The formation of side products, i.e. homopolymer poly(2,6-dimethylphenylene oxide) (PPO) and 3,3',5,5'-tetramethyl-4,4'-diphenoquinone (DPQ), could be suppressed by slowly adding the DMP to the reaction system. A likely phenoxonium intermediate mechanism is derived from this copolymerization study.