Accession Number:

AD0903906

Title:

Thermooxidation Studies of the Quinoxaline System and Certain Benzimidazole Copolymer Systems. Part 1. Initial Studies on the Mechanism of Thermooxidation of the Quinoxaline System. Part 2. Synthesis and Evaluation of Thermooxidative Properties of a Series of Benzimidazole Copolymers

Descriptive Note:

Annual technical rept. 1 Feb 1971-31 Jan 1972

Corporate Author:

WRIGHT STATE UNIV DAYTON OH DEPT OF CHEMISTRY

Report Date:

1972-03-01

Pagination or Media Count:

161.0

Abstract:

The synthesis and oxidation solution and pyrolytic of certain quinoxaline model compounds is reported. Pyrolytic oxidation 400-500 C yielded benzonitrile, oxides of carbon and cyanogen. Solution oxidation yielded the corresponding pyrazine dicarboxylic acids. Subsequent pyrolytic oxidation of the pyrazine dicarboxylic acids produced benzonitrile, oxides of carbon, cyanogen, and the corresponding pyrazine derivative. Evidence for thermal oxidation intermediates oxygenated at the carboxylic ring adjacent to the heterocyclic ring is presented by product isolation and spectral data. The results are discussed in terms of an initial oxygenation mechanism for the quinoxaline system. A series of copolymers of benzimidazole units with amides, benzimides and benzimidazolones was synthesized and evaluated for their thermooxidative stabilities and solubilities. Each copolymer exhibited the solubility characteristic of its least soluble component. The benzimidazolebenzimidazolone copolymer exhibited greater thermal stability than PBI homopolymer. The other copolymers exhibited stabilities comparable to PBI. Concentrated sulfuric acid was successfully used as a film casting solvent for polybenzimidazolone BBB, PBI, and copolymer PBIBBB. All three films exhibited superior thermooxidative stabilities.

Subject Categories:

  • Polymer Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE