Multidimensional NMR of fluoropolymers

Modern NMR instruments have enormous flexibility to control pulse timing events, so that an elaborate array of multidimensional NMR experiments can be implemented for complex structure determination. Implementation of these methods is particularly relevant for fluoropolymers, which often have three NMR active nuclei ( H, and that are ideally suited for creating useful multidimensional NMR experiments. 

In this chapter, we describe a variety of methodologies for applying multidimensional NMR (mostly 2D- and some 3D-NMR) for the characterization of fluoropolymers. Space limitations preclude a comprehensive survey of the literature. Instead, a few of the primary methodologies are described involving combined use of multidimensional NMR methods for structure elucidation. Then, a selected group of papers were reviewed to illustrate the applications of these methodologies to the characterization of some of the most common classes of fluoropolymers, including homo- and copolymers with poly(vinylidene fluoride), fluorinated polyethers, fluori-nated ionomers, poly(vinyl fluoride) and its copolymers, and polytetrafluoroethylene (PTFE) and its copolymers. 

The similar NMR properties of F and as described in Table 24.1 means that most NMR experiments used for would also work to degree for F. With modern technologies, a large variety of multidimensional NMR experiments are feasible to probe the correlation within these three nuclei of fluoropolymers, of which the most basic are homonuclear 2D-NMR experiments discussed in Chapter 24.2.2. When... 

The following sections describe selected applications of various methodologies involving combined use of the multidimensional NMR experiments described in section 24.2. The sections are divided based on the major classes of fluoropolymers which have commercial and/or scientific significance. These include PVDFs, perflu-orinated polyethers, poly(chlorotrifluoroethylene)s, fluorinated ionomeric polymers, and PTFEs. The applications serve as examples of how multidimensional NMR experiments can be combined to solve stmcture problems in each of these fluoropolymer classes. 

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