COMPOSITION AND MICROSTRUCTURE OF FLUOROPOLYMERS - HIGH-TEMPERATURE HIGH-RESOLUTION FT-NMR

Nuclear magnetic resonance has been a powerful tool for the study of polymer composition and structure for nearly 30 years. High-resolution NMR has been much more useful than broad-line NMR due to the correlation between specific resonances and specific nuclear sites within the polymer. However, high-resolution NMR has until recently1 only been applicable to those polymers that are either soluble or have a low melt viscosity at a sufficiently low temperature such that an NMR spectrum may be obtained. Fluoropolymers do not fall into either of these two classes. Initial studies of fluoropolymers by medium resolution NMR2 indicated that sufficient resolution could be obtained for melt samples of tetrafluoroethylene-hexafluoropropylene copolymer at 310 °C to allow a compositional analysis. These studies and later solution studies of general polymer microstructure have indicated that better resolution and sensitivity would be necessary to allow the extraction of accurate compositions and microstructural detail. We report here the development and application of high-temperature high-resolution FT NMR to compositional and microstructural studies of fluoropolymers: poly(tetrafluoroethylene) and poly(tetrafluoroethylene) copolymers with hexafluoropropene and ethylene. © 1979, American Chemical Society. All rights reserved.