Tsuchikawa Satoru, Siesler H W
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
Appl Spectrosc. 2003 Jun;57(6):675-81. doi: 10.1366/000370203322005373.
Fourier transform near-infrared (FT-NIR) transmission spectroscopy was applied to monitor the diffusion process of deuterium-labeled molecules in hardwood (Beech). The results are compared with previous data obtained on softwood (Sitka spruce) in order to consistently understand the state of order in cellulose of wood. The saturation accessibility and diffusion rate varied characteristically with the OH groups in different states of order in the wood substance, the diffusants, and the wood species, respectively. The variation of saturation accessibility should be associated with the fundamental difference of the fine structure such as the microfibrils in the wood substance. The effect of the anatomical cellular structure on the accessibility was reflected in the variation of the diffusion rate with the wood species. The size effect of the diffusants also played an important role for the diffusion process in wood. Since the volumetric percentage of wood fibers and wood rays is relatively similar, the dichroic effects due to the anisotropy of the cellulose chains were apparently diminished. Finally, we proposed a new interpretation of the fine structure of the microfibrils in the cell wall by comparing a series of results from hardwood and softwood. Each elementary fibril in the hardwood has a more homogeneous arrangement in the microfibrils compared to that in the softwood.
傅里叶变换近红外（FT-NIR）透射光谱法被用于监测氘标记分子在硬木（山毛榉）中的扩散过程。将结果与之前在软木（西加云杉）上获得的数据进行比较，以便连贯地了解木材纤维素中的有序状态。饱和可及性和扩散速率分别随木材物质中不同有序状态的羟基、扩散剂和木材种类而呈现出特征性变化。饱和可及性的变化应与木材物质中微纤丝等精细结构的根本差异相关。解剖细胞结构对可及性的影响体现在扩散速率随木材种类的变化上。扩散剂的尺寸效应在木材中的扩散过程中也起着重要作用。由于木纤维和木射线的体积百分比相对相似，纤维素链各向异性引起的二向色性效应明显减弱。最后，通过比较硬木和软木的一系列结果，我们对细胞壁中微纤丝的精细结构提出了一种新的解释。与软木相比，硬木中的每个基本原纤丝在微纤丝中的排列更均匀。
