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Simple Trends in the Methylene and α-Substituent Regions of NMR Spectra of Vinyl Polymers

✍ Scribed by Guglielmo Monaco; Rosario G. Viglione

Publisher
John Wiley and Sons
Year
2004
Tongue
English
Weight
165 KB
Volume
205
Category
Article
ISSN
1022-1352

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✦ Synopsis

Abstract

Summary: Chemical shift trends in the methylene and α substituent regions of ^13^C NMR spectra of vinyl polymers have been analyzed in terms of a three‐state rotational isomeric states (RIS) model and the γ‐gauche effect. In this framework, it has been demonstrated that the three sequencing rules observed for poly(propylene) can also be expected to work for many other vinyl polymers. The first two rules, justified in terms of the conformational perturbability of stereosequences, turn out to be respected by a considerable number of NMR spectra. On the other hand, the same spectral data are in substantial disagreement with the third rule. An explanation is proposed for this breakdown.

Sketches of the three conformations expected for rotation on the two prochiral bonds flanking the methine carbon of a vinyl polymer.

magnified imageSketches of the three conformations expected for rotation on the two prochiral bonds flanking the methine carbon of a vinyl polymer.

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