Syndiotactic Polystyrene Containingortho-Dichlorobenzene: Crystal Structure of the Clathrate Form
| Autor: | Vittorio Petraccone, Oreste Tarallo |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Materials science
Polymers and Plastics Organic Chemistry Clathrate hydrate Crystal structure Condensed Matter Physics Symmetry (physics) chemistry.chemical_compound chemistry Group (periodic table) Tacticity Polymer chemistry Materials Chemistry Molecule Polystyrene Physical and Theoretical Chemistry Ortho-dichlorobenzene |
| Zdroj: | Macromolecular Chemistry and Physics. 206:672-679 |
| ISSN: | 1521-3935 1022-1352 |
| DOI: | 10.1002/macp.200400387 |
| Popis: | The crystal structure of the clathrate form of syndiotactic polystyrene containing ortho-dichlorobenze-ne has been determined, and compared with those of the other crystalline clathrate structures of s-Ps already known. This guest molecule, characterized by a quite different shape and volume from the others already described, gives rise to the only example of clathrate form of s-PS presenting a statistical orthorhombic symmetry (cell constants a = 17.5 A, b = 22.9 A, c = 7.8 A and space group Ccmb). This symmetry is generated by the random coexistence in the crystals of domains, with the same monocliulc P21/a symmetry found for the other clathrate forms, that can be realized by two different but energetically equivalent, packings of the chains. 0 The unit cell constants are a = 17.5 A, b = 14.4 A, c = 7.8 A and γ = 127.4°. The shape of the guest molecule produces a significant modification of the cavities (if compared to δ form) realized mainly through a shift of the ac layers of chains delimiting the cavities along the a axis direction that turns out in the highest y value found for these kinds of structures. |
| Databáze: | OpenAIRE |
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