Effect of Thermal Modification on Wood Cell Structures Observed by Pulsed-Field-Gradient Stimulated-Echo NMR

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• 作者：Pivi M. Kekkonen ; Ville-Veikko Telkki ; Jukka Jokisaari
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：November 4, 2010
• 年：2010
• 卷：114
• 期：43
• 页码：18693-18697
• 全文大小：327K
• 年卷期：v.114,no.43(November 4, 2010)
• ISSN：1932-7455

文摘

Thermal modification is an environment friendly method for increasing the lifetime and usability of timber products. In our previous work (J. Phys. Chem. B 2009, 113, 1080), we introduced a pulsed-field-gradient stimulated-echo (PGSTE) NMR based method that enables determining the highly anisotropic size distribution of voids (pores) inside wood cell structures in three orthogonal directions. Here, we demonstrate that the method can be used to quantify the effect of thermal modification on the pore dimensions in Pinus sylvestris pine wood. The results show that the modification decreases the dimensions of lumens inside tracheid cells both in the longitudinal and two transverse directions. However, the relative decrease becomes smaller at the highest modification temperature, implying partial destruction of the cell wall structure. The decrease is larger in the radial direction than in the tangential direction at all the modification temperatures.