Aromatic Polymers for Thermally Fibers and Films I) Polybenzimidazoles II) Poly(1,3,4-Oxadiazoles)

Item

Title
Aromatic Polymers for Thermally Fibers and Films I) Polybenzimidazoles II) Poly(1,3,4-Oxadiazoles)
Date
1963
Date Issued
1963-01
Publisher
Wright-Patterson Air Force Base, OH : Directorate of Materials & Processes, Aeronautical Systems Division, Air Force Systems Command
DoD Project
7320 - Fibrous Materials for Decelerators and Structures
DoD Task
None Given
Laboratory
Directorate of Materials & Processes
Distribution Conflict
No
Distribution Classification
1
Abstract
Dimethylacetamide and dimethylsulfoxide have been successfully employed as dry-spinning solvents for poly-2,2'-(m­-phenylene)-5,5'-bibenzimidazole. The physical properties of both fibers appear to be comparable. Since dimethylacetamide produces a lighter colored yarn and in general lends itself to easier solvent removal, it emerges as the more desirable solvent for dry-spinning operations.
The fibers exhibit remarkably high resistance to hydrolysis and thermal ageing, although under the more realistic condition of air ageing the thermal properties are not nearly as impressive as under nitrogen. The N-H bond in polybenzimidazoles is suspect as the weak link leading to degradation in the hot oven. To test this hypothesis N-substituted polymers were prepared via the methylation of N-sodio polybenzimidazoles.
Oriented and crystalline polyhydrazide fibers can be converted by a unique cyclodehydration reaction into oriented and crystalline fibers of poly(1,3,4-oxadiazoles). Conversion of fibers (T/E/Mi = 5/24/94) of the polyhydrazide derived from equimolar amounts of isophthalic dihydrazide and terephthaloyl chloride (OIOT) gave fibers (T/E/Mi = 2.6/3.1/124) of poly(1,3-/1,4-phenylene-2,5-­(1,3,4-oxadiazole), PODZ-I/T, which have excellent retention of their fiber structure even when exposed to temperatures up to 400°C. for prolonged periods of time. Such heat treatments afford a final polyoxadiazole fiber (T/E/Mi = 1.2/1.2/90). The chemical structure of model compounds containing up to 13 alternating rings consisting of 2,5-(1,3,4-oxadiazole), m- and p-phenylene moieties was found to be stable up to 400-450°C. This is in agreement with observed stabilities of the corresponding polymer towards thermal degradation.
Index Abstract
Contrails only
Identifier
AD0299030
DTIC Record Exists
No
Report Availability
Full text available
Creator
Frazer, August H.
Wallenberger, Fred T.
Kane, James J.
Extent
40
Corporate Author
E. I. du Pont de Nemours & Company
Report Number
ASD TDR 62-964, p. 57-95
Provenance
Lockheed Martin Missiles & Fire Control
Type
article
Relation
This paper was presented at the Directorate of Materials and Processes "Symposium on Fibrous Materials" held in Dayton, Ohio, on 16-17 October 1962
Format
1 online resource (40 pages)
Is Part Of
Symposium on Fibrous Materials
Media
ASDTRD62-964paper04.pdf

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Items with "Has Part: Aromatic Polymers for Thermally Fibers and Films I) Polybenzimidazoles II) Poly(1,3,4-Oxadiazoles)"
Title Class
Symposium on Fibrous Materials