New X-ray crystallographic data on crystalline polymers of methyl sorbate: Conformational energy calculations for different configurational hypotheses
✍ Scribed by P. Corradini; R. Napolitano; V. Petraccone; B. Pirozzi; A. Tuzi
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- English
- Weight
- 549 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0014-3057
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✦ Synopsis
Conformational calculations have been performed on chains oI poly(mcthyl sorbatc) having different configurations; the results of these calculations have been compared with NMR and X-ra~ data obtained for two kinds of poly(methyl sorbate) recently synthesized. The polymer having a prcvailingt~ erythro configuration has a chain axis c = 4.8 A and a conformation of minimum energy in accordance with that reported in a previous paper. The polymer having a prevailingly threo configuration has a chain axis c = 9.4 A compatible with a regular conformation of low energy having two constitutional repeating units and in accordance with the distribution of intensities in the X-ray spcctra. The t,xo ideal conformations found are compatible with the presence of configurational defects.