13C and 15N Solid-State NMR of Copolymers of Nylon 6 and 7: Observation of a Stable Pseudohexagonal Phase
Technical rept. 1 Jun 92-31 May 93,
UNIVERSITY OF SOUTHERN MISSISSIPPI HATTIESBURG DEPT OF POLYMER SCIENCE
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We have synthesized and characterized a series of nylon copolymers based on the even-odd A-B monomer combination, caprolactam and enantholactam. The nylon 6-co-7 samples obtained were found to possess physical properties which directly correlate with copolymer composition. We have determined degrees and types of crystallinity for these materials using a combination of thermal, NMR and X-ray measurements. The homopolymers each display highly ordered alpha- crystallites while the copolymers possess less-ordered domains that decrease in alpha-like characteristics down to the 11 copolymer which possesses a thermodynamically stable pseudohexagonal ordered phase. The 13C T1 values determined for the annealed 11 copolymer were shorter than those of crystalline regions of homopolymers, comparable to those observed for amorphous domains in melt quenched nylon 6 and nylon 7 homopolymers, and significantly longer than the values for precipitated and annealed 11 nylon 11-co-12 sample.
- Polymer Chemistry