Oriented specimens of isotactic cis-l,4-poly(3-methyl-l,3-pentadiene) exhibit two crystalline modifications characterized, respectively, by the expected two-fobd helical conformation with a fiber repeat of 8,02 A and by a three-fold helix with c = 9,97 A. The latter highly contracted structure is pr
On the Crystal Structure of Isotactic cis-1,4-Poly(1,3-pentadiene)
✍ Scribed by Roberto Napolitano
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 173 KB
- Volume
- 15
- Category
- Article
- ISSN
- 1022-1344
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✦ Synopsis
Abstract
Summary: A comparison between the crystal structure of isotactic cis‐1,4‐poly(1,3‐pentadiene) previously predicted by molecular mechanics calculations and that successively determined by other authors by experimental data is reported. The agreement between the two structures is very good as far as the space group, the unit cell parameters and the conformation of the polymer chain are concerned. The mode of packing of the chains proposed in the experimental crystal structure is very similar to that found as relative minimum in the previous energy calculations. The coexistence, in different amounts, of these two modes of packing is suggested by the analysis of the simulated X‐ray spectra and by the results of new energy calculations.
A mode of packing of chains of isotactic cis‐1,4‐poly(1,3‐pentadiene).
magnified imageA mode of packing of chains of isotactic cis‐1,4‐poly(1,3‐pentadiene).
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