Studies of the Breakdown Mechanism of Polymers. V. The Thermal Decomposition of Some Polybenzimidazoles
Technical rept. May 1968-May 1969
AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OH
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The thermal breakdown of 4 samples of 2,2-m-phenylene-5,5-bi- benzimidazole and of 6 other polybenzimidazoles was studied between 200 and 650 C. Decomposition studies showed that PBI not only have a strong tendency to absorb water, but also contain oxygen in various other forms, possibly end groups, intermediate amide and hydroxy imidazoline structures, secondary ether and phenolic groups, imidazole-water complexes, and unknown oxidation products. Thermal breakdown of the aromatic rings proceeds via formation of hydrogen and methane, and decomposition of the imidazole structure yields some hydrogen cyanide and ammonia. Most of the nitrogen, however, is retained in the residue, possibly in the form of other heterocyclic, highly condensed structures.
- Polymer Chemistry