High‐Resolution Solid‐State ¹³C‐NMR Spectroscopy of Polymers [New Analytical Methods (37)]

Abstract

Dedicated to Professor Helmut Dorfel on the occasion of his 60th birthdayUntil a few years ago, solid-state nuclear resonance yielded spectra containing broad lines only. Meanwhile, CP/MAS-NMR spectroscopy has provided a method which gives narrow nuclear resonance lines from a solid-state specimen as well. Using this technique, it is now possible to produce spectra of "rare" nuclei (I3C, 29Si, I5N etc.) which are resolved in terms of chemical structure. The analytical capabilities of NMR spectroscopy can be applied to the solid state: it may be that it is necessary to identify compounds in the solid state because, for example, a solvent would alter the coordination sphere, or that it is desired to monitor chemical reactions in the solid state, for example the baking of an enamel. Where a substance in the solid state is concerned, high-resolution I3C-NMR spectroscopy provides not only information about the chemical structure, but also about the solid state itself. To mention just a few examples, information on the conformation, crystal structure and molecular dynamics, as well as molecular miscibility is given. This opens up a broad spectrum of applications, from a statement concerning the crystal modification of an active substance in ready-to-use pharmaceutical preparations, e.g. tablets, to the question of whether two polymers are miscible with one another at a molecular level.

Synthesis and Characterization of Styrene-Butadiene Block Copolymer/Silicate Hybrid Materials via the Sol-Gel Process I. Four-Arm Star Styrene-Butadiene Block Copolymer/Silica Hybrids

“…9 -11 Although the measured Tfp( C) may contain the spin-spin contribution Tf!tt- ( 1) it is reasonable to explain Tfp(C) data of amorphous polymers by molecular dynamics since in amorphous polymers the measured TUC) is predominantly ( 80%) determined by spin-lattice process. 12 Shown in Figures 5(A) and (B) are the plots of logarithmic 13 C resonance intensity vs. 13 C spin-locking time for PBD chains (peak at 130 ppm) and PS chains (peak at 40 ppm), respectively, in SB-4A and its hybrids. ,/ms The corresponding T 1 P(C) values are listed in Table IV.…”

Characterization and stability of silanized and polymercoated octadecyl reversed phases

“…30 s [22,23]. The CP method, on the other hand, is intrinsically selective [24]. Quantification is sometimes problematic (see the beginning of this section), but the determination of the several time constants involved in the CP process can be used to determine (differences in) motional behaviour of the sample molecules.…”

NMR Studies of Molecular Motion and Compatibility in Polymer Blends of Poly(epichlorohydrin)/Poly(methyl methacrylate)

“…This work studies the differences of molecular motion of PECH polymer chain 210 for two blend films (transparent film and opaque film) with PMMA and bulk by NMR. We observed the behavior of PMMA polymer chain by solid state 13 C NMR. In the case of opaque film we observed the behavior of PECH polymer chain about the blend cast from tetrahydrofuran (THF)/H 2 O to know the influence of compatibility by blending poor soluvent in cast solvent.…”

“…We measured T 1 by solid state high resolution 13 C NMR spectra to observe the molecular behavior of PMMA polymer chain in bulk and blend films. Solid state high resolution 13 C NMR spectra were measured by high power proton decoupling (DD) and magic angle spinning (MAS).…”

“…13 · 18 Especially spin-lattice relaxation time of 1 H and spin diffusion have been applied to many studies on polymer blends. 18 -21 Above the glass transition temperature Tg, 13 C high resolution NMR spectra are obtainable for solid polymer even by conventional NMR spectrometers used for liquids. Molecular mobilities of solid polyesters above Tg were studied by F. Horii et al in this method.…”