Characterization of poly(1-chloro-1-fluoroethylene) fluoropolymer using H-1/C-13/F-19 triple resonance 3D-NMR

Ordinarily, it is possible to distinguish between mm/rr and mr/rm triad stereosequences using standard NMR experiments; however, distinction between the resonances of mm and rr triads can only be made if a spectrum from a stereoregular polymer of known relative configuration is available. This paper reports the use of a 3D H-1/C-13/F-19 triple resonance NMR experiment to unambiguously determine the resonance assignments for mm, mr/rm, and rr triad stereosequences in poly(1-chloro-1-fluoroethylene) without resorting to the preparation of stereoregular polymer having known relative configuration. Additionally, this technique provides significantly better dispersion than 1D- and 2D-NMR methods. Consequently, it was possible to completely resolve and assign H-1, C-13, and F-19 resonances from methylenes centered in tetrad structures and fluorine atoms centered in pentad structures.