Conformational and packing energy for the three crystalline forms of isotactic poly-α-butene

✍ Scribed by P. Corradini; R. Napolitano; V. Petraccone; B. Pirozzi

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 352 KB
• Volume: 20
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(84)90072-7

✦ Synopsis

Calculations of the conformational and of the packing energy have been performed for the three main crystalline modifications of isotactic poly-~-butene. Calculations of the conformational energy have been performed first through minimizations of the energy of the isolated chains under the constraint of maintaining the experimental helical symmetry and periodicity tbr each modification. In this way accurate conformations have been determined for the helices corresponding to the three modifications. These conformations have been used for calculation of the packing energy of the three modifications of poly-~-butene. The considered space groups are those experimentally observed: for each modification also the possibility of statistical up and down positioning of the chains has been examined. The differences between the packing energies are greater than those between the conformational energies for the three different modifications. The relative stabilities of the three modifications of poly-~-butene, as obtained by our calculations, are discussed.