Structural Characterization of Nylon 7 by Solid-State NMR, DSC, and ATR- FTIR
Abstract
Samples of commercial nylon 7 were given different thermal or precipitation histories. Structure and crystallinity were followed by DSC, solid-state NMR, and attenuated total reflectance FTIR (ATR-FTIR). Delta H and T(sub m) values ranged from 52 to 93 J/g and 228 to 242 deg C, respectively. Surprisingly, annealing did not give material with the greatest delta H although it possessed the highest melting point. Solid-state 13C and 15N NMR methods were used to observe the amorphous and crystalline fractions. For example, the amide nitrogens show resonances near 86.5 ppm in amorphous domains, near 84 ppm in alpha-crystals, and near 89 ppm in gamma-crystals. 15N CP/MAS spectra of solution cast samples contained peaks consistent with all three domains in various intensity ratios but with the gamma-peak being the most intense for most samples. Solid-state 13C spectra contained peaks which supported the presence of these phases but with the alpha-phase peaks predominating.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 07, 1993
- Accession Number
- ADA265800
Entities
People
- C. G. Johnson
- L. J. Mathias
Organizations
- University of Southern Mississippi