几种木材中硅石的研究

要实现木材-无机质复合材的人工模拟,其关键还是在于研究和探讨木材生物矿化的机理,因此要对木材中无机物的情况进行研究,从而获取生物矿化所形成的木材/无机质复合材料的形成机理,以此来指导木材的生物改性或木材/无机复合材的仿生合成。本文采用光学显微镜对几种木材/二氧化硅生物矿化复合材中硅石的分布进行观察发现:硅石主要分布在木射线细胞中,大量的晶体在木射线细胞以及轴向薄壁细胞中均有分布;采用重量法对几种木材/二氧化硅生物矿化复合材中二氧化硅含量情况进行测定表明:子京、山油柑、柚木、柠檬桉、山竹子等5种木材/二氧化硅生物矿化复合材中二氧化硅含量分别为1.5106%、0.8941%、0.8654%、0.2155%、0.1676%。     

木材细胞中二氧化硅的吸收、运输与聚积

硅石在很多木材细胞中都可见(如紫果冷杉、樟科等),它与木材本身构成了一种复合材料即木材/无机质复合材,使木材的物理力学性能得以改善,克服了木材自身的一些缺陷(如易腐、易燃、尺寸不稳定性、各向异性等).作者根据前人对木材细胞中二氧化硅(SiO2)的分布、形态和含量的初步分析,归纳总结木材细胞中二氧化硅(SiO2)的形成过程及其影响因素即木材细胞中SiO2的吸收、运输及聚积,影响木材细胞中SiO2的吸收、运输及聚积的因素,为进一步研究木材细胞中硅生物矿化的形成过程做准备.     

生物矿化原理与木材纳米结构复合材料

为促进传统木材改性技术产生新的发展 ,将生物矿化概念导入到木材科学与技术的研究领域中。本文综述了生物体系中生物矿化作用的基本内涵 ,探讨了基于这些原理之上的木质基纳米材料控制合成的构想 ,即通过立木形成层细胞分生的有机分子和无机离子在界面处的相互作用来设置矿化位 ,调节微环境 ,建立饱和溶液、提供有机质、搬运离子、加入添加剂等来控制生物矿化作用的方向和过程 ,实现用活立木制备木材纳米结构复合材。     

热处理复合硅石溶液改性杨木的性能及机理研究北大核心

将硅石溶液经有机硅烷杂化后浸渍人工林杨木,再对其进行热处理,测试分析改性材的物理力学性能、化学结构及形貌特征,探讨木材联合改性机理。结果表明:1)复合硅石溶液改性使杨木的密度、强度和阻燃性均显著提高,但尺寸稳定性欠佳,热处理可明显增强其尺寸稳定性和阻燃性;2)改性剂填充固化于木材细胞腔,甚至渗入细胞壁中,可起到有效的增强作用;3)热处理可促进改性剂与木材组分发生稳固的Si—O—Si化学结合;4)联合改性材中Si原子配位数增多,缩聚固化程度更高,稳定性增强。复合硅石溶液/热处理联合改性是一种应用前景广阔的绿色木材改性技术。     

日本皂荚的木材解剖

作者对日本皂英的木材进行了解剖学研究。木材特征为环孔材，单管孔或复管孔，在晚材中可见管孔链和管孔团，导管分子为单穿孔，轴向薄壁组织为环管状或翼状环管状，同型射线，常为多列射线２－５个细胞宽。     

薄壁型巨龙竹秆材化学成分分析

巨龙竹是至目前为止所发现最粗的竹子,单株竹材生物量居同类竹材之首。对3-5年生薄壁型巨龙竹秆材不同部位的主要化学成分进行了测定,包括灰分、木素、综纤维素、多戊糖、冷水抽出物、热水抽出物、1%Na OH抽出物、乙醚抽出物、苯-醇抽出物。结果表明：薄壁型巨龙竹的木素、综纤维素、多戊糖的含量与常用纸浆造纸原料木材接近,灰分含量介于木材和草类原料之间;除冷水抽出物外,薄壁型巨龙竹其它抽出物含量在秆高方向上均表现出递增的分布规律。     

杉木／二氧化硅复合材料的制备及其尺寸稳定性

用满细胞法将高固含量的二氧化硅溶胶压注入杉木,制备出杉木/二氧化硅复合材料,并用扫描电子显微镜(SEM)对复合材的微观结构进行了表征。研究表明:复合材的抗膨胀系数(ASE)、阻吸湿系数(MEE)分别增加了32.6%和14.8%,材料的尺寸稳定性能明显提高。     

溶胶-凝胶法调控木材表面附着二氧化硅薄膜的研究

采用溶胶-凝胶法使木材表面附着二氧化硅薄膜,以改良木材表面疏水性、抗老化性等性能。通过SEM、EDAX、FTIR等研究二氧化硅的形态、结构、分布及其与木材表面结合的方式等,使用抗老化性、润湿角表征二氧化硅改良材的表面性能。结果表明:木材表面附着一层厚度为40μm的二氧化硅薄膜,且薄膜的厚度随着浸渍时间的增加而增加。该二氧化硅薄膜具有疏水性,润湿角的平均值为101.6°,其润湿角随着浸渍时间的增加而增加,且改良材的润湿角在人工老化后,其变化量明显小于素材,抗老化性能得到了很大提高。改良材的抗光变色能力是素材的2倍以上。     

植物激素与木材形成

综述了植物激素在树木维管组织分化中的作用．生长素是调节木质部细胞分化的主要因子；细胞分裂素在诱导分生组织发端和分生细胞分化上起重要作用；赤霉素促进纤维的形成，赤霉素和生长素结合使用，可有效地促进次生木质部中纤维分化；乙烯能促进树木韧皮部和木质部分化。还讨沦了木材形成过程中的三个主要问题：生长素含量的多少直接控制了沿树轴木质部导管、管胞的大小和密度；外界环境因子影响木质部细胞分化；温带落叶阔叶树环孔材和散孔材形成的机理，生长素控制环孔材树种早材宽导管的形成以及晚材窄导管和纤维形成的假说。对今后改善树木木材的质和量上有一定参考价值。     

木腐菌及其腐朽机理研究进展

木腐菌可以有效地改善针叶材心材的渗透性,可用于辅助阔叶材散孔材年轮的鉴定,木腐菌及其所分泌的酶还可作为生物技术应用于木材工业,如生物制浆预处理、生物漂白以及木材酶解为糖的预处理等领域。本文从褐腐、白腐、软腐、竹材及人造板等几个方面出发,对国内外腐朽机理的研究现状进行了较为系统、全面的介绍,旨在使学者了解真菌选择性地降解木竹材的化学成分和细胞各部分的知识,为木竹材的保护和合理利用提供参考。     

无机质复合木材研究进展

简述了扩散法和溶胶-凝胶法制备无机质复合木材的研究现状和机理, 指出无机质复合木材的制备正朝着多元复合、无机有机共混的方向发展。今后研究应在先进研究方法的基础上, 在不削弱木材多孔结构的前提下, 以强化细胞壁为主要目标制备无机质复合木材, 赋予人工林木材高强度、高性能。     

Fire-resisting properties in several TiO2 wood-inorganic composites and their topochemistry

Summary A study of the wood-inorganic composites prepared by the sol-gel process with a metal alkoxide indicated that an inorganic modification of wood with TiO₂ gels from tetraisopropoxytitanium (TPT) can not improve its properties due to the formation of the gels in the cell lumina by high hydrolysis rate of TPT. In this study, therefore, titanium alkoxides or titanium chelates which have the lower rate of hydrolysis and subsequent polycondensation than TPT were used for preparing TiO₂ wood-inorganic composites to study the topochemical effects of the TiO₂ gels for the property enhancement of wood. As a result, it was found by SEM-EDXA analysis that the TiO₂ gels deposited within the cell walls could improve the properties of wood in dimensional stability and fire-resistance, whereas for the gels in the cell lumina, property enhancement could not be achieved, as observed in SiO₂ wood-inorganic composites.This research has been performed in Dept. of Wood Sci. & Technol., Kyoto UniversityThis research was supported by a Grant-in-Aid for Scientific Research (B) (No. 06453176, 1994.4–1996.3) from the Ministry of Education, Science, and Culture, Japan. The authors were grateful to Nippon Soda Co., Ltd. for providing titanic reagents.     

Nanoscale in Wood,Nanowood and Wood—Inorganic Nanocomposites

In order to introduce nano science and technology(NST) into the research field of wood science and technology,and promote the research of wood science and wood-inorganic composites to nanoscale ,some new concepts,such as the nano space in wood,nano structure units of wood and nanowood are put forward in this paper based on the layer structure of wood cell wall and the pile-up model of its main components.Furthermore,the process of preparing nanowood is discussed,and wood-inorganic nanocomposites may be operated in three ways with wood (matrix) and inorganic filler phase in 0-2,0-3 or 2-3 dimensions respectively.The following results are obtained:(1) The nanoscale voids in wood indicate that wood has inherent space to accommodate nanosized materials,such as nanoparticles,nanotubes and nanosticks;(2) According to the size from top down,the nano structure units in wood can be classified as :nanolayers,nano CMF (cellulose microfibril) and matrixd,nano crystallite units and cellulose chain clusters,and these can theroretically from nanowood;(3) The preparation of wood-inorganic nanocomposites can be operated on 0-2,0-3 or 2-3 dimensions.     

日本在无机质复合木材领域的研究进展*

无机质复合木材是近年来木材化学改性领域中研究活跃的主题之一，文中简要叙述了溶胶—凝胶法制备木材—无机质复合材料的基本反应历程，介绍了近年来日本在无机质复合木材研究方面的进展情况。     

Several SiO2 wood-inorganic composites and their fire-resisting properties

Summary In a study on the SiO₂ wood-inorganic composites prepared by the sol-gel process with tetraethoxysilane (TEOS), it is more appropriate to use safer agents than TEOS, considering the operational and processing environments. In this study, therefore, methyltrimethoxysilane (MTMOS) was used to prepare the SiO₂ wood-inorganic composites, and comparative studies were made with TEOS. Resultingly, SiO₂ wood-inorganic composites could be successfully prepared from MTMOS reaction system, as in TEOS system, with its lower concentration, and both composites had SiO₂ gels specifically formed within the cell walls from moisture-conditioned wood specimens. On this SiO₂ composites, the water-repellent properties were added most effectively with a molar ratio of 2-heptadecafluorooctylethyltrimethoxysilane (HFOETMOS) to alcohol being 1/250 and 1/180 for TEOS and MTMOS reaction systems, respectively. On the other hand, fire-resisting properties were tried to add to SiO₂ composites with several fire-resisting agents. The fire-resisting agents in the obtained composites are not, however, stable and leached out readily. Therefore, a small addition of HFOETMOS was tested to the MTMOS and TEOS reaction systems with fire-resisting agents. The obtained results clearly indicated that HFOETMOS could restrain the fire-resisting agents to be leached from the composites, and that composites from MTMOS system were superior to TEOS system on the antileachability. Therefore, MTMOS can be appropriate for displacement of TEOS as a chemical agent to prepare SiO₂ wood-inorganic composites.This research has been performed in Department of Wood Science and Technology, Faculty of Agriculture, Kyoto University, Kyoto, Japan.This research was supported by a Grant-in-Aid for Scientific Research (B) (No. 06453176, 1994.4–1996.3) from the Ministry of Education, Science, and Culture, Japan.     

柠檬桉水泥刨花板若干工艺因子的研究

通过对柠檬桉制造水泥刨花板的可能性、水泥/刨花的比率、水泥种类与板材性能关系等因素的研究,结果表明:使用添加剂或对木材进行热水处理可以使柠檬桉成为适宜制造水泥刨花板的树种。     

Na2O-SiO2 wood-inorganic composites prepared by the sol-gel process and their fire-resistant properties

For enhancing fire-resistant properties, a binary system to prepare wood-inorganic composites was studied by adding sodium methoxide (SM) or sodium acetate (SA) to a reaction system for SiO₂ composites. Compared with the SiO₂ composites, both the Na₂O-SiO₂ composites prepared could be greatly improved up to 600°C-700°C (glowing). From scanning electron microscopic observations, this enhanced fire resistance was assumed to be due to chemical and physicochemical effects, such as dehydration and carbonization of wood by Na₂O gel. The glassy layer and intumescent structure formed over the cell walls were thought to prevent oxidation and heat transfer from proceeding into the inner portion of the wood cell walls. However, the reaction medium with SM to prepare Na₂O-SiO₂ composites was basic, whereas that with SA was rather neutral. In addition, in the latter composites, most of the inorganic gel was formed within the cell wall, retaining the porous structure characteristic of wood. Therefore, the Na₂O-SiO₂ composites prepared with SA can be concluded to be preferable for practical purposes.Part of this report was presented at the 50th annual meeting of the Japan Wood Research Society, Kyoto, April 2000     

桉木基复合材料研究进展

桉树作为我国主要的人工林树种之一,具有品种多、生长速度快等优点,在缓解我国木材供 需矛盾上发挥了重要作用。由于桉木存在高生长应力、节疤、易变形开裂等劣势,目前工业上主要用作 纸浆、纤维板或胶合板和单板层积材的芯板,其利用方式单一,附加值较低。近年来研究者们以桉木与 塑料、竹材等材料为原料制备复合材料,展现出良好的尺寸稳定性、力学性能、阻燃性、抗菌性等性能, 有效地提高了桉木的利用价值,拓宽了桉木在人造板、集装箱等领域的应用。文章分别介绍了桉木 / 塑 料、桉木 / 竹、桉木 / 水泥、桉木 / 无机物 4 种复合材料,并对其制备工艺、性能等方面的研究进展进行 综述。