Structural Characterization of Nylon 7 by Solid-State NMR, DSC, and ATR- FTIR
Technical rept. 1 Jun 92-31 May 93,
UNIVERSITY OF SOUTHERN MISSISSIPPI HATTIESBURG DEPT OF POLYMER SCIENCE
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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 Tsub m values ranged from 52 to 93 Jg 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 CPMAS 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.
- Physical Chemistry
- Solid State Physics