13C NMR spectra of nylon 6/12 copolymers and related model compounds

• Published in: European polymer journal Vol. 36; no. 7; pp. 1301 - 1311
• Main Authors: Goodman, Isaac, Maitland, Derek J., Kehayoglou, Aristides H.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-07-2000; Elsevier
• Subjects: 13C NMR spectroscopy; Applied sciences; Chain structure; Exact sciences and technology; Model compounds; Nylon 6/12 copolymers; Organic polymers; Physicochemistry of polymers; Model compounds; Nylon 6/12 copolymers; Chain structure; 13C NMR spectroscopy; Random copolymer; Molecular structure; Spectrum analysis; Model compound; Caprolactam copolymer; Experimental study; Microstructure; NMR spectrum; Amide 12 copolymer
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/S0014-3057(99)00194-9

The
13C NMR spectra of model mono- to tetra-amides containing CO, (CH
2)
5 and (CH
2)
11 groups in varied sequential arrangements have been used to reinterpret assignments previously proposed for signals in the spectra of nylon 6/12 random copolyamides. From the CO signal intensities, the mean nylon 6 and nylon 12 homo-unit block lengths have been determined in copolyamides prepared by rapid (ca. 15 min) activated anionic lactam copolymerisation at 180°C. The results are virtually identical with published data for equilibrium copolymers of similar co-unit ratios made by hydrolytic polymerisation at 260°C in reaction times >144 h. Maximum sequential randomness occurs at ca. 50–60 mol% nylon 6 component, coinciding with minima in the thermal and solid-state properties.