Poly(aryl ether phenylquinoxalines) via anionic ring opening polymerization of macrocycles

A cyclic poly(aryl ether phenylquinoxaline) was prepared via the self-polymerization of 1 in an N-methyl-2-pyrrolidone (NMP) solution containing base using a pseudo-high dilution polymerization condition. The macrocycle formation of 1 was carried out in the presence of potassium carbonate in a NMP/toluene solvent mixture at a solids content of 1%. The water generated by phenoxide formation was removed as an azeotrope with toluene 170°C. A concentrated solution of the macrocycle was added to the reaction mixture over an 8 hour period. The reaction was allowed to proceed for an additional 24h to ensure quantitative reaction. A number of characterization techniques were used to study the cyclization of 1 including GPC, HPLC, H NMR and matrix-assisted laser desorption ionization (MALDI) mass spectroscopy. The MALDI-TOF mass spectrum of the cyclization of 1 clearly showed that a mixture of macrocycles is obtained, with the expected distribution of molecular weights. Facile ring opening polymerization of the cyclic poly(aryl ether phenylquinoxaline) oligomers was accomplished with a nucleophilic initiator. High polymer was obtained for each polymerization temperature (η =0.4-0.5 dl/g in NMP), however, prolonged reaction time resulted in significant gel formation. The Tg's were high and commensurate with the high molecular weight linear analog (250°C).