Carbon-13 NMR of polyethylenes: Correlation of the crystalline component T1 with structure
| Autor: | Rakesh Popli, D. E. Axelson, P. J. M. Mathieu, Leo Mandelkern |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
Relaxation (NMR)
General Engineering Spin–lattice relaxation Thermodynamics Carbon-13 NMR Polyethylene law.invention Condensed Matter::Soft Condensed Matter Condensed Matter::Materials Science Crystallinity chemistry.chemical_compound Crystallography symbols.namesake chemistry law symbols Crystallite Crystallization Raman spectroscopy |
| Zdroj: | Journal of Polymer Science: Polymer Physics Edition. 21:2319-2335 |
| ISSN: | 1542-9385 0098-1273 |
| DOI: | 10.1002/pol.1983.180211109 |
| Popis: | The carbon-13 spin-lattice relaxation times T1 of the crystalline portion of a set of polyethylenes have been studied. Chain structure and crystallization conditions have been varied over the widest possible extremes so that large differences are developed in the level of crystallinity, the supermolecular structure, and the crystallite thickness. Concomitantly, the observed crystalline T1 values cover the extraordinarily wide range of about 40–4500 s. They bear a one-to-one relation with the crystallite thickness, which is found to be the key structural variable determining this property. A correlation with the temperature for the α-transition can be established, which implies a similar type of segmental motions for the two phenomena. Major changes in the interfacial structure can also have a drastic influence on the value for the crystalline T1. Analysis of the magnetization decay curve also allows for a quantitative determination of the degree of crystallinity, which is found to be in excellent agreement with the corresponding value found from Raman spectroscopy. |
| Databáze: | OpenAIRE |
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