Characterization of 1:1 Random Copolymers Obtained from 6-, 7-, 11-, and 12-Carbon Amino Acids
Technical rept. 1 Jun 1992-31 May 1993
UNIVERSITY OF SOUTHERN MISSISSIPPI HATTIESBURG DEPT OF POLYMER SCIENCE
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Copolymers were prepared from the title amino acids by melt condensation under dry nitrogen. The resulting copolymers were characterized by solution and solid-state NMR, FTIR, DSC, and WAXD. Solution NMR spectra at 75.5 MHz showed multiple peaks with almost equal intensities in the carbonyl region indicating random copolymer formation with no evidence of end-group peaks confirming high molecular weight. Solid-state 13C at 100.6 MHz and 15 N at 20.3 MHz spectra of most solution cast films contained peaks consistent with the gamma-form crystallites sigma Nl5 ca 89 being the predominant ordered phase. Only nylon 6-co-7 formed almost exclusive alpha-form on solution casting sigma Nl5 84.5. Nylon 7-co-11 formed the alpha-form almost exclusively from the melt but gave a combination of alpha- and gamma-phases sigma N15 84.5 and 88.7 on solution casting. The copolymers possessed 3-component 13 C T, values ranging from 21 to 97 s for the slowest-relaxing component, indicating less- ordered domains than for the homopolymers.
- Polymer Chemistry