【作者】 陈志林；

【导师】 左铁镛； 叶克林；

【作者基本信息】 北京工业大学 ， 材料学， 2003， 博士

【摘要】 陶瓷化复合木材是以木材为基体，无机非金属物质为增强体，通过适当的复合工艺而得到的一种新型复合材料。以复合材料理论和技术方法来研究陶瓷化复合木材，赋予木材和陶瓷这两种传统材料以新的内涵，具有明确的科学目的和意义，即：改进和提高人工林木材物理力学性能、耐腐性、阻燃性和尺寸稳定性：借鉴材料研究理论和技术，利用边缘学科、交叉学科研究的优势来开展创新研究，为开发新的木质材料制造技术提供科学依据和理论基础。本文以我国丰富的人工林I-69杨树(Populus deltoides)木材为原料，采用溶胶-凝胶的方法来制备陶瓷化复合木材。为了获得性能优良的材料，满足在家具用材、室内装饰用材和室外建筑用材等应用方面的要求，在制备方法上采用先制备溶胶，然后浸注木材的工艺技术，利用真空加压设备强化溶胶向木材的渗透和扩散，保证溶胶最大限度地进入木材内部，其目的是一方面在木材孔隙内形成凝胶，起到填充作用，另一方面为凝胶与木材细胞壁发生键合作用提供条件。研究结果表明：1． 凝胶对木材孔隙的填充是有效的。凝胶主要填充在导管和木纤维的细胞腔内，沿着细胞壁分布，凝胶紧密而充实，呈棒状、片装：在木材导管胞间层孔隙内凝胶呈串珠状，而细胞壁纹孔内的凝胶呈颗粒状。与利用细胞壁吸附水水解获得溶胶的研究方法相比，陶瓷化复合木材的平均增重率由36． 1％提高到81． 3％。2． 红外光谱研究表明，陶瓷化复合木材960cm-1处新增加了一个吸收峰，它是凝胶与木材细胞壁发生缩合反应形成了Si-O-C键引起的。比较X光电北京工业大学工学博士学位论文子能谱(xPs)，陶瓷化复合木材与凝胶的siZp的谱峰产生了化学位移，说明其化学环境发生了变化，从另一个方面证实了Si一0一C的存在。 3.溶胶进入木材后，所发生的核心反应是缩合反应，它一方面是自身的缩合反应，另一方面是溶胶与木材细胞壁上的轻基发生缩合反应，其结果是5102凝胶部分与纤维素发生键合，部分以物理填充方式存在于木材空隙内，从而实现将无机510:复合到木材组织内的目的，使材料性能得到优化或改善。与未处理杨树木材相比，陶瓷化复合木材顺纹抗压强度和径向抗压强度分别提高了60.4%和102.3%;弦向干缩率为未处理材的46.1%。 4.通过甲基三乙氧基硅烷(MTES)与正硅酸乙醋(TEOS)共水解，在凝胶网络中引入一CH3，利用这种改性溶胶来制备陶瓷化复合木材，可以进一步改善材料的性能。一CH3可以降低凝胶网络内应力，改善凝胶的脆性，同时疏水基团一CH3还可以降低凝胶的吸水性，因而材料的尺寸稳定性、耐风化和耐腐朽性能都得到提高。试验表明陶瓷化复合木材在沸水煮沸1.5h，重量损失6.2%;在水中浸泡2h，吸水增重5.4%;在室温饱和蒸汽里处理12h，其吸湿性为无机质复合木材的40%，相当于对照木材的50%;增重率为80.5%的陶瓷化复合木材，其径向、弦向和体积干缩系数分别相当于对照杨木的50.4%、46.1%和49.6%。在室外风化27Od的陶瓷化复合木材重量损失率是3.4%，为对照杨木的49.3%，而顺纹抗压强度下降了20%;在土壤中自然腐朽27Od，重量减少8、9%，径向抗压强度下降了19.7%。陶瓷化复合木材有效减缓了木材热分解的温度，在750℃时重量保存率为76%，提高了陶瓷化复合木材的阻燃性能。 上述表明，本文在科学理论方面，提出了陶瓷化复合木材的复合结构模型，即凝胶既填充木材孔隙而且还与细胞壁发生键合作用。在工艺方法上，采用先制备溶胶，然后浸注木材的工艺方法具有原料利用率高、提高增重率的优点;采用甲基三乙氧基硅烷和正硅酸乙醋共水解的方法，将甲基引入陶瓷化复合木摘要材的凝胶内部，所制备的材料具有尺寸稳定性好、具有耐风化和耐腐朽性，强度高的特点;首次利用X射线光电子能谱，发现了SiZp、015和Cls谱峰发生了明显的化学位移，证实了Si一0一C键合作用的存在。更多还原

【Abstract】 Ceramic-wood composite is a kind of new composite materials, which is produced by an appropriate composite method with wood as matrix and inorganic ceramic as reinforcement. The study of Ceramic-wood composite based on composite material’s theory and technology endowed the wood and ceramic of those two traditional materials with new meaning and had specifically scientific and significant meaning as follows: Many properties of plantation wood were improved, such as mechanics, decay resistance, fire-resistance and dimensional stability. This creative research carried out by making use of theory and technology in materials research field and the superiorities of marginal and inter-cross disciplines provided the theoretical and scientific bases for the development new wood-based composite.In this paper, ceramic-wood composite was produced by the method of sol-gel with 1-69 poplar (Populus deltoides), which was abundant in our country, as the raw materials. In order to obtain materials of high performance to meet the need of furniture material, inner decorating material and outer building material, we took the method of preparing the Sol at first and then impregnating the wood. The sol was impregnated and diffused into the wood by force through a vacancy-press equipment, which insured the sol impregnate into the inner of the wood at its maximum, thus the sol can form gel in the holes of the wood reacting as the purpose of filling on the one hand, on the other hand, it provided the conditions for the happen of bonding effect between the gel and the cell wall of wood.The study showed:1.The gel was effective in filling the spaces of the wood, it mainly filled in the woody fibers and vessels of the cellular clearances and distributed along the cell wall. The gel grains were homogenously distributed and took the shape of stick and slice. The gel grains in the holes of wood’s vessel cell looked like a string of beads, while the gel in pit of the cell wall took the form of grains. The average weight percent gain of the wood increased to 81.3% compared to the former studyof 36.1%.2.X-ray Photoelectron Spectroscopy (XPS) showed that a new absorbing apex came forth in the position of 960cm-1 owing to the form of Si-O-C as the result of condensation reactions between gel and cell wall.3.When sol entered into the wood, the core reaction was condensation, including the condensation reactions between sol itself and condensation reactions between the sol and the hydroxyls on the cell wall of the wood, which leaded to one part of SiO2 gel bonded with fibrin and another part of SiO2 Gel consisted in holes of wood in the physical filling way, it realized the goal of composite the inorganic SiO2 to the inner tissue of wood, thus the performances of the materials were optimized or improved. Compared to the untreated the Populous, the radial compress and longitudinal compress of ceramic-wood composite improved 60.4% and 102.3% respectively; the tangential shrink ratio of the ceramic-wood composite was 46.1% of the untreated wood.4.The performances of ceramic-wood composite were improved more when the methyl was imported to the net of gel by making use of co-hydroxylation between MTES (methyl triethoxy silane) and TEOS (tetraethyl orthosilicate). The performances of Ceramic-wood composite such as decay resistance, dimensional stability and effloresce resistance were improved owing to the introduction of the cymene, which reducing the inner stress of gel net, meliorating the brittleness and reducing the absorbility of gel. The study showed that when the ceramic-wood composite was soaked in the boiling water for 1.5 hours, the weight loss was 6.2%; the weight gain was 5.4% when it was marinated in the water for 2 hours; The hygroscopes of the ceramic-wood composite were only 40% and 50% of wood-inorganic composites and untreated the Populous respectively when it was treated under the saturated steam at normal temperature. As to the ceramic-wood composite of 80.5% WPG (weight percent gain), its radial, tangential and volume shrink c更多还原