Exploration of Advanced Characterization Techniques for Molecular Composites
Abstract
The techniques of solid state nuclear magnetic resonance, fluorescence spectroscopy, electron spin resonance, and x-ray diffraction were applied to characterize aspects of the solid state structures of rigid rod polymers and their blends with flexible polymers. NMR and fluorescence spectroscopies were used to investigate the degree to which the rigid rod - flexible polymers blends exist as phase separated systems. It was found that these materials form primarily phase segregated structures, a condition which limits the reinforcing potential of rigid rod polymers in molecular composites. Most specimens also reinforcing potential of rigid rod polymers in molecular composites. Most specimens also exhibited NMR signals indicative of mobile, and presumably lower molecular weight, species. It is postulated that these mobile species are either water or residual acid from which the materials are processed. Information regarding the location of the mobile species in the structures exhibited by rigid rod polymers and their blends with flexible polymers is deduced from NMR. Electron spin resonance measurements confirmed that free radicals are generated during mechanically stressing rigid rod polymer fibers. The as-processed fibers contained appreciable levels of free radicals and annealing at elevated temperatures caused a decrease in the free radical concentration by a factor of three. X-ray diffraction experiments were conducted at elevated pressure in a diamond anvil cell. The observed diffraction pattern is suggestive of the formation of a more ordered structure at elevated pressures. Keywords: PBT(Poly(Benzobisthiazole); ABPBI (Poly(2,5(6) Benzimidazole); Nylon 6.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1986
- Accession Number
- ADA168102
Entities
People
- B. M. Fanconi
- D. L. Vanderhart
- F. W. Wang
- K. L. Devries
- R. K. Eby
Organizations
- Wright Laboratory