13C and 15N Solid-State NMR of Copolymers of Nylon 6 and 7: Observation of a Stable Pseudohexagonal Phase
Abstract
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 1:1 copolymer which possesses a thermodynamically stable pseudohexagonal ordered phase. The 13C T1 values determined for the annealed 1:1 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 1:1 nylon 11-co-12 sample.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 07, 1993
- Accession Number
- ADA265799
Entities
People
- C. G. Johnson
- L. J. Mathias
Organizations
- University of Southern Mississippi