FTIR studies of conformational disorder: crystal perfecting in long chain n-alkanes
| Autor: | Stephen J. Spells, Jean-Philippe Gorce |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Alkane
chemistry.chemical_classification N alkanes Polymers and Plastics Stereochemistry Annealing (metallurgy) Organic Chemistry Polyethylene Crystal chemistry.chemical_compound Crystallography chemistry Materials Chemistry Fourier transform infrared spectroscopy Conformational isomerism Long chain |
| Zdroj: | Polymer. 45:3297-3303 |
| ISSN: | 0032-3861 |
| DOI: | 10.1016/j.polymer.2004.03.034 |
| Popis: | The low temperature FTIR spectra of long chain n-alkanes C198H398 and C246H494, crystallised from solution in both extended and once-folded forms, have been investigated in the CH2 wagging region. Successive annealing and cooling stages result in a significant reduction in the number of non-planar C–C bond conformers in all cases. This is evidence of a ‘perfecting’ process within the crystals. The time dependence of this behaviour shows that, on raising the annealing temperature, the level of disorder reaches a maximum before declining. In addition, in a continuous heating run on once-folded C198H398, all types of conformational disorder except end-gauche bonds are shown to pass through a maximum near 118 °C, in the region of the transformation to extended chain crystals |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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