The Dielectric Properties of Wood IV : On Dielectric Dispersions of Oven-dried Wood
The Dielectric Properties of Wood IV : On Dielectric Dispersions of Oven-dried Wood
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木材的介电特性 IV : 关于烘干木材的介电分散
DOI：
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发表时间：
1970
期刊：
影响因子：
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通讯作者：
Tadashi Yamada
中科院分区：
文献类型：
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作者：
M. Norimoto;Tadashi Yamada
本文研究了烘干木材的介电损耗。木材中存在三种电介质缺陷。低温下高频区的介电吸收位置与粘弹性吸收位置一致，其弛豫过程可能与木材物质无序区CH_（20）H基团的运动有关。烘干后的木村木木在室温下的吸收出现在低频范围，这可能是由于导电材料的存在，并受到材料在木材中的形状的影响。高温下极低频的吸收可能与非晶区分子的链段运动和热降解有关。引言虽然已经做了许多关于木材的介电性能的调查，有一些报告，旨在澄清介电和粘弹性松弛之间的关系。本研究的目的是调查的介电和：粘弹性性能的木材在很宽的频率和温度范围内，并澄清与松弛分子运动的模式。据报道，在室温下，在107至108 Hz的频率范围内，烘干木材的介电分散体存在，并且与无定形相中的OH基团的取向有关。然而，还没有讨论在非常低的频率范围内是否发生其他色散。本文从以下三个方面进行论述。(1)低温下高频范围内的介电和粘弹性色散。(2)将烘干的KUSUNOKI（Cinnamomum coreora SIEB.）在室温下在低频范围内。(3)烘干木材和纤维素在高温下以极低频率分散。* 发表于日本木材研究学会第20次会议，东京，1970年9月。** 前一篇论文，J. Jap. Wood Res. Soc.，16，364（1970）中所述。* 木材物理学分部。36 NORIMOTO，YAMADA：木材的介电性能实验用于介电实验的样品示于表1中。在0.3至10 Hz的频率范围和-70至140 ℃的温度范围内进行测量。电感臂电桥和电阻臂电桥分别用于30至10 Hz和0.3至10 Hz的频率范围。表1.用于介电测量的样品。材料处理葡萄糖纤维二糖棉处理3% HCl在90°C几个小时Avicel粉末（200目）Whatmann纤维素山毛榉木聚糖KUSUNOKI热水和酒精苯提取SUGI I I L*，5 mm * HOONOKI！I L，1.5mm HINOKI I L，Imm热水和醇苯萃取I i Block I L，5 mm醇苯萃取I
-In this paper, the dielectric absorptions of oven-dried wood were investigated. There existed three dielectric absorptions in wood. The position of dielectric absorption in high frequency range at low temperature coincided with that of viscoelastic one, and the relaxation process may be associated with the motion of CH20H groups in the disordered region of wood substances. The absorption of oven-dried KUSUNOKI appeared in low frequency range at room temperature may be due to the existence of the conductive material and was influenced by the shape of the material in wood. The absorption in very low frequency range at high temperature may be associated with the segmental motion of molecules in the amorphous region accompanied by thermal degradation. Introduction Although many investigations on dielectric properties of wood have been done, there are a few reports which intend to clarify the relation between dielectric and viscoelastic relaxation. The aim of this study is to investigate the dielectric and the:viscoelastic properties of wood over the wide ranges of frequency and temperature and to clarify the mode of molecular motion concerned with the relaxations. It has been reported that a dielectric dispersion of oven-dried wood exists in the frequency range of 107 to 108 Hz at room temperature and is associated with the orientation of OH groups in the amorphous phase. However, it has not been discussed whether other dispersions do occur or not at very low frequency range. In this paper, the following three points are discussed. (1) The dielectric and the viscoelastic dispersion in high frequency range at low temperature. (2) The dispersions of oven-dried KUSUNOKI (Cinnamomum camphora SIEB.) in low frequency range at room temperature. (3) The dispersion of oven-dried wood and cellulose in very low frequency at high temperature. * Presented at the 20th Meeting of Japan Wood Research Society, Tokyo, Sep. 1970. ** Previous Paper, J. Jap. Wood Res. Soc., 16, 364 (1970). *** Division of Wood Physics. 36NORIMOTO, YAMADA: The Dielectric Properties of Wood Experimental The samples for the dielectric experiment are shown in Table 1. The me·· asurement was made over the frequency range of 0.3 to 10 Hz and the temperature range of -70 to 140°C. The inductive and the resistive ratio arm bridges were used for the frequency range of 30 to 10 and 0.3 to 10 Hz, respectively. Table 1. Samples used for the dielectric measurement. Material Treatment Glucose Cellobiose Cotton treated with 3% HCl for several hours at 90°C Avicel Powder (200 mesh) Whatmann cellulose Beeech xylan KUSUNOKI hot water and alcohol-benzene extraction SUGI I I L*,5mm* HOONOKI ! I L, 1.5mm HINOKI I L, Imm hot water and alcohol-benzene extraction I i Block I L, 5mm alcohol-benzene extraction I