Woodceramics Prepared from Wood Powder/Phenolated Wood Composite

In this paper, composites were made from wood powder and its phenolated product, and then were carbonized into woodceramics. The effects of the content of the phenolated wood in the composites on the forming ability, size, density, compressive strength, volume electrical resistivity, and specific surface area of the woodceramics were investigated. It is suggested that in the preparation of woodceramics, phenolic resin can possibly be substituted totally by phenolated wood that is the main constituent of liquefied wood.     

Humidity Sensor Characteristics of Woodceramics

The humidity sensor characteristics of Woodceramics were investigated. The Woodceramics used in this experiment were prepared at 650–900°C. The size of specimens selected was 1 × 1 × 10 mm . One was used as-cut and the other was polished. Above 700°C, the resistance of the specimen was below 50 and the decrease of resistance with increasing relative humidity was small. The specimen prepared at 650°C had a resistance of about 1 k. The resistance of as-cut specimens decreased with increase in relative humidity, but that of the polished specimen did not change significantly. The difference between as-cut and polished samples was explained by the differences in surface micro-structure.     

凹凸棒石-针铁矿改性麦秸木质陶瓷的微观结构

以凹凸棒石、针铁矿和小麦秸秆为原料,添加少量的环氧树脂作为黏结剂,在适宜的温度和气氛下煅烧,同步完成了生物质碳化、凹凸棒石热活化及针铁矿的还原,获得了具有高气孔率和强磁性的凹凸棒石-针铁矿改性麦秸木质陶瓷,利用XRD和SEM分析了原料质量比及焙烧温度对其物相及微观结构的影响。结果表明:凹凸棒石-针铁矿改性麦秸木质陶瓷是一种非晶态多孔质碳素材料,在相同温度下,原料的质量比对其物相几乎无影响;随着焙烧温度的升高,凹凸棒石的特征衍射峰逐渐消失,凹凸棒石-针铁矿改性麦秸木质陶瓷中有新的物相产生。     

先驱体转化法制备SiOC多孔木质陶瓷

用杉木木粉浸渍高分子先驱体有机硅树脂,改变烧结温度和保温时间制备 SiOC 多孔木质陶瓷。用 X 射线衍射、扫描电子显微镜、红外光谱及热分析对样品的物相及微观结构进行了表征,并用四探针法测试样品的电学性能。结果表明：样品由 SiOC 玻璃相、α-石英和自由碳组成,化学结构主要含有 Si—O,Si—O—R,Si—C,C=C 和 C—H2。α-石英颗粒呈球状分布在样品的孔洞表面。样品在 Ar 中具有较好的热稳定性。但由于 SiOC 玻璃相和自由碳的氧化反应,样品在 O2中的质量损失较大。当烧结温度达 1200 ℃,保温 1h 时,样品具有较低的体积电阻率（0.03 ·cm）。     

大麻杆木质陶瓷的微晶结构与其吸油性能的研究

以酚醛树脂和大麻麻杆为原料制备一种木质陶瓷，用SEM，FTIR，XRD技术对所制得的木质陶瓷物相、微观结构和物理化学结构变化的影响进行了表征。SEM结果表明，木质陶瓷呈现三维网络有孔结构，FTIR、XRD测试结构表明，木质陶瓷含有C=C、C=0、C-O-C和C-H等基团的类石墨结构材料，并由无定形，乱层结构和六方结构氧化石墨3种成分，并随着炭化温度的升高，无定形结构向乱层结构和六方结构转化，晶面间距减少，但其吸油能力增加。     

木材陶瓷

较全面地介绍了一种新型环境材料木材陶瓷的出现、发展和现有水平，分析了它各方面的优势，并在此基础上推测了它的研究、应用前景。     

New porous carbon materials,Woodceramics: Development and fundamental properties

Woodceramics are new porous carbon materials obtained by carbonizing wood or woody material impregnated with thermosetting resin such as phenol resin in a vacuum furnace. During the carbonizing process, thermosetting resin changes into glassy carbon, which has superior corrosion resistance and mechanical strength, reinforces the material and suppresses the fissures and warps (caused by the porous structure specific to wood) that develop during thermoforming. The dimension, weight decrease rate, and electrical characteristics depend on the thermoforming temperature. The manufacturing method of Woodceramics is introduced in this paper and various industrial uses, such as electromagnetic shields, are discussed.     

Electromagnetic Shielding Properties of Woodceramics Made from Wastepaper

Woodceramics are new porous carbon materials, which are made by impregnating woody materials with phenol resin and then thermoformed in a vacuum furnace and these have been shown to have electromagnetic shielding properties. In the recycling of wastepaper, ways of using the wastepaper other than for paper pulp are needed to be developed. In this study, we made Woodceramics from handbill advertisement paper and telephone directory paper, and measured their electromagnetic shielding properties in order to find new uses for wastepaper. The results showed that the Woodceramics made from wastepaper had an electric shielding effectiveness of 30 dB for 100 MHz and 40 to 43 dB for 300 MHz or higher, and had a magnetic shielding effectiveness of 30 dB for 100 MHz and 37 dB for about 400 MHz. An electric equivalent circuit of the pore model in the Woodceramics is introduced. In addition, it is proposed that the excellent electromagnetic shielding effectiveness of the Woodceramics is caused by dielectric loss.     

新型环境材料--木质陶瓷的研究

本文综述了一类新型环境材料——木质陶瓷在国内外的研究进展。针对木质陶瓷制备过程的不同工艺路线、原材料选取、熔融浸渍体种类等方面做了详细论述,并介绍了木质陶瓷的微观结构。木质陶瓷具有优异的电磁屏蔽、温度-湿度传感、摩擦学性能等,以及特殊的结构特征。作为一种新型的结构和功能材料,其有着广阔的应用前景。本文最后总结了木质陶瓷的应用及其发展方向。     

碳纤维增强层状木材陶瓷的界面结构及受力分析

为了研究纤维增强木材陶瓷复合材料的界面结构与受力情况, 利用液化木材、炭粉和碳纤维制备层状结构木材陶瓷。采用扫描电镜和高分辨率透射电镜对其基本结构与界面进行观测, 并通过显微拉曼光谱检测拉伸试件G’峰的位移来判断界面的结合情况。同时, 基于双线性软化本构模型, 采用Abaqus软件对界面层在应力传递中的作用与方式进行了数值分析。扫描电镜与透射电镜的观测表明: 碳纤维增强木材陶瓷具有清晰的层状结构, 且无定形碳与玻璃碳之间存在强界面结合。拉曼光谱的测试发现: 加压烧结试件拉伸后的G’峰向低波数的位移更大, 证明加压烧结能够改善玻璃碳与碳纤维之间界面的结合强度。数值分析显示: 在受力过程中, 界面层对碳纤维与基体材料之间的应力传递起着重要作用, 同时, 随着界面层强度与厚度的增加, 其所能承受的载荷增大, 传递给基体材料的等效应力也随之增加。