Multidimensional NMR of Fluoropolymers

19F DOSY diffusion‐NMR spectroscopy of fluoropolymers

“…[37,38] NMR studies of these and other fluoropolymers are very exciting and useful. [39] The presence of three NMR active nuclei, the high natural abundance of both 1 H and 19 F and the unique NMR properties of 19 F produce NMR spectra with an amazing amount of information. Recently, it has been shown that 19 F detected DOSY experiments could be used to distinguish between the resonances of polymer chain-ends and other branching structures in a series of fluoropolymers.…”

“…[40][41][42] Generally, the performance of 19 F NMR experiments on fluoropolymers creates some unique complications that often interfere with detection of important signals. [39] These factors include: (1) the presence of many scalar couplings among 1 H, 19 F and 13 C; (2) the large magnitudes of many 19 F homonuclear couplings (especially 2 J FF ); (3) the large 19 F chemical shift range; and (4) the low solubility of these materials (which requires that experiments be performed at high temperatures).…”

Multidimensional 19F NMR Analyses of Terpolymers from Vinylidene Fluoride (VDF)–Hexafluoropropylene (HFP)–Tetrafluoroethylene (TFE)

“…Another difficulty with the NMR studies of this terpolymer, which may be present in the NMR studies of most fluoropolymers, is the large chemical shift range of 19 F. While the large chemical shift range may present an advantage (there are likely to be fewer overlaps of peaks in the 19 F spectrum compared to 1 H spectrum of the terpolymer), it also presents a challenge with regards to uniform excitation of the entire spectral width, especially in multidimensional experiments. 17,18 This requires a probe with a short 19 F 90°pulse width. In addition, the NMR probe for studying fluoropolymers should be made of minimal 19 F containing materials.…”