Identification of Free and Bound Water Content in wood by means of NMR Relaxometry
Ryszard GUZENDA, Wieslaw OLEK Department of Mechanical Engineering and Thermal Techniques Cultural University of Poznan, ul. Wojska Polskiego 28, 60-637 Poznan, Poland Hanna M. BARANOWSKA Department of Physics Cultural University of Poznan, ul. Wojska Polskiego 28, 60-637 Poznan, Poland
The advanced techniques of Nuclear Magnetic Resonance (NMR) relaxometry enable to determine not only moisture content in wood but also contents of free and bound water. Simultaneous identification of both subsystems of water in wood is especially important in investigations of moisture transfer in wood. This paper presents the analysis of the relationship between the spin-lattice relaxation time and moisture content of the most common Polish wood species i.e. Scots pine. Samples for the relaxation time determination were obtained from both heartwood and sapwood of pine. The CracSpin computer program using the spin-grouping method was applied to perform the separation of the spin-lattice relaxation times. For moisture contents above the Fiber Saturation Point (FSP) there were obtained two components of the relaxation time related to two free and bound water. While below the FSP only one component was identified. The obtained results were generalized by empirical models. Differences between relaxation times for heartwood and sapwood were discussed.
Publication Source: Proceedings of the 12th International Symposium on Nondestructive Testing of Wood University of Western Hungary, Sopron, 13-15 September 2000, ISBN 963 7180 88 5 Publisher: University of Western Hungary, H 9400 Sopron, P.O.Box 132, FAX: +36 99 311 103
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