Synthesis of Quinoxaline Polymers Curable by Intramolecular Cyclization.

摘要

Polyphenylquinoxalines containing 2,2'-bis(phenylethynyl) diphenyl moieties along the polymer backbone have been synthesized. These polymers underwent a novel curing reaction consisting of an intramolecular cyclization to a dibenzoanthracene structure, thereby increasing the rigidity and correspondingly the Tg of the polymers. The significance of this type of reaction as a major breakthrough in the processing of high-temperature polymers was shown by the properties obtained for the best system: an initial Tg of 215 C; cure at 245 C with no evolution of volatiles; a Tg after cure of 365 C. The initial Tg and cure temperature are compatible with current processing equipment. The nonvolatile intramolecular cure, as has been demonstrated in the phenylquinoxaline polymer system, should provde tough resins for reinforced composites with use temperatures far exceeding processing temperatures. (Author)