Homonuclear Separated Local-Field Spectroscopy by Magnetization-Exchange NMR |
D.E. Demco Department of Physics, Technical University, 3400 Cluj-Napoca, Romania X. Filip, C. Filip Institute for Isotopic and Molecular Technology, 3400 Cluj-Napoca, Romania D. Chira and O. Cozar Faculty of Physics, University Babes-Bolyai, 3400 Cluj-Napoca, Romania |
Received: July 7, 1997 |
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The possibility to perform homonuclear separated-local field NMR spectroscopy by magnetization-exchange is presented. Solid-state one-dimensional proton magnetization-exchange NMR is used to investigate intergroup residual dipolar couplings in cis-1,4-polybutadiene elastomer. A three-spin model is employed, in which the CH- and CH2-protons are considered to be coupled by residual dipolar interactions. The magnetization-exchange process between the CH- and the CH2-group in the regime of short mixing time provides valuable insight regarding molecular order. The spin-system response reflects well-localized dipolar interactions. The residual intergroup dipolar couplings are measured along the average polymer-chain direction for different temperatures. The dynamic order parameter along the chains is also evaluated. |
DOI: 10.12693/APhysPolA.92.1135 PACS numbers: 33.25.+k, 61.41.+e |