13C and 1H NMR (Nuclear Magnetic Resonance) Studies of Solid Polyolefines.
UNIVERSITY OF EAST ANGLIA NORWICH (ENGLAND) SCHOOL OF CHEMICAL SCIENCES
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The basis of H1 and C13 high-resolution NMR investigations of solid polymers is outlined. The C13 NMR spectra of solid syndiotactic and isotactic polypropene are discussed and their interpretation in terms of conformation and chain-packing effects are reviewed. The effects of decreasing temperature on the C13 high-resolution spectrum of an annealed sample of isotactic polypropene is described and interpreted in terms of the crystal structure. The question of the proportion of the sample giving rise to C13 signals is addressed and some results reported. The main cause for observing only part of the total sample is shown to be the H1 rotating frame spin-lattice relaxation behaviour. The H1 spin-lattice relaxation and spectral characteristics of a number of polyolefine samples are summarised and the role of spin-diffusion discussed.