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
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 benzimidazole/benzimidazolone 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 (PBI/BBB). All three films exhibited superior thermooxidative stabilities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1972
- Accession Number
- AD0903906
Entities
People
- James J. Kane
- Robert T. Conley
- Sirong Lu
- Subrata Ghosh
Organizations
- Wright State University