【作者】 吕文华；

【导师】 赵广杰；

【作者基本信息】 北京林业大学 ， 木材科学与技术， 2004， 博士

【摘要】 聚合物／蒙脱土(MMT)纳米插层材料，是目前研究最多、最引人注目的复合材料。我国的蒙脱土矿藏资源十分丰富，独特的结构，适宜的离子交换容量，优良的力学性能及低廉的价格，使得蒙脱土成为制备新型高性能纳米插层复合材料的最重要的一类无机物。应用纳米插层复合技术，使蒙脱土以纳米尺寸对木材进行改良或改性是木材科学领域的前沿课题，属国际上的创新思考和实践，具有重大的理论意义和实用价值。本论文首次提出了木材／蒙脱土纳米插层复合的技术路线；对蒙脱土进行了全面系统的钠化改型、有机改性研究，成功制备了有机蒙脱土；首次制备了水溶性酚醛树脂(PF)／蒙脱土纳米复合材料，并确定了最佳工艺；首次以水溶性PF为中间介质，制备了木材／蒙脱土纳米插层复合材料(WMNC)。本论文的探索性研究，为木材改性提出了新的思路，为木材／无机复合材料的研究开拓了新的途径。 本研究利用具有层状晶体结构的蒙脱土的水膨润性、层间阳离子的可交换性，在对蒙脱土进行钠化改型、有机改性的基础上，借助水溶性PF，通过真空浸渍等处理，使蒙脱土与木材在纳米尺度分子水平上复合，制备了(WMNC)。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、傅立叶变换红外光谱仪(FTIR)、热重-差热分析仪(TG-DTA)等分析手段得到以下主要结论： (1) 钠化土层间距增大，结晶度变差，活性和胶体性能增强。经钠化改型后，该蒙脱土的膨胀容、膨润值和阳离子交换容量(CEC)等各项指标均比原矿有较大幅度提高。钠化的最佳工艺条件为：原土分散浓度15％、碳酸钠加入量4％、反应温度60℃、反应时间1h。 (2) 蒙脱土的有机化改性对蒙脱土纳米复合材料的制备有着重要影响。蒙脱土有机改性后，层间距显著扩大，部分片层被完全剥离自由分散，由亲水性变为疏水性，热稳定性明显提高。蒙脱土有机化的最佳工艺条件为；C18改性剂、粒度200目、陈化24h、蒙脱土分散浓度5％、改性剂浓度0.3mol／L、介质酸碱度pH值为4、硫酸作质子剂、改性剂过量50％、反应温度80℃、反应时间1.5-2h、真空干燥、干燥温度＜120℃、烘干至含水率(1％～3％)。主要影响因子的作用顺序为：改性剂用量在＞蒙脱土分散浓度＞反应时间＞介质pH值＞反应温度。中文摘要(3)有机蒙脱土与水溶性酚醛树脂有良好相容性，易得到部分插层部分剥离型的酚 醛树脂/蒙脱土纳米插层复合体(PMNC)，PMNC的热性能较PF有明显改善，PMNc 中的蒙脱土与酚醛树脂分子间可能通过氧原子发生了较强连接。苯酚、甲醛、 有机蒙脱土一步复合的一步法，影响因子多，反应复杂，研究难度大。水溶性 酚醛树脂合成后再与蒙脱土复合即两步法，蒙脱土被扩层、剥离的效果更好。 PMNC纳米插层复合的最佳工艺:CIS有机改性蒙脱土、酚醛树脂合成配比(F/P 摩尔比)为1.5、5%的蒙脱土、直接加热固化、低温长时间固化。(4)以水溶性酚醛树脂(PF)为复合中间介质制备的木材/蒙脱土纳米插层复合材料 (W MNC)，蒙脱土主要是填充于细胞腔等大孔隙、附着于细胞壁表面以及插入细 胞壁的纹孔腔中，部分剥离片层进入到木材细胞壁的无定形区。wMNC中木材 的结晶度降低。具有很大径厚比的二维蒙脱土纳米片层，对木材纳米空隙的插 入或填充有很大的取向性或选择性。wMNC的缔合轻基、醚键增多，蒙脱土与 木材之间可能发生了氢键作用或其它化学结合。 WMNC的热性能在大于450℃高 温区明显提高。采用室温、高真空浸渍处理工艺，水溶性酚醛树脂是较好的中 间介质，蒙脱土在处理液中的分散浓度以边材3%、心材5%较佳，抽提处理、 少量水分可明显改善杉木心材渗透性。在较低蒙脱土质量分数下，杉木/蒙脱土纳米插层复合材(wMNC)的吸湿性、吸水性、尺寸稳定性、抗水流失性、顺纹抗压强度、耐磨性、氧指数等性能均较酚醛树脂浸渍木有一定提高。由于单纯酚醛树脂浸渍处理对杉木性能的改善作用已较显著，而且蒙脱土在WMNC复合材中的质量分数太小(<3%)，WMNC的纳米复合效应并不显著。但木材/蒙脱土纳米复合材料的性能存在很大的发展潜力和开发前景，值得进一步深入研究。更多还原

【Abstract】 Polymer/Montmorillonite (MMT) intercalation nanocomposite is one of the most widely studied and most promising composites. China is rich in Ca-MMT mineral resources. Due to its particular intercalation chemistry and nanoscale layers with very high aspect ratio and high strength, ion-exchangeable and swellable MMT play an important role in producing high-performance intercalation nanocomposites. The intercalation nano-compounding of wood and MMT is creative thinking and practice, which has important scientific significance and attractive application prospect. The intercalation compounding of organic wood and inorganic MMT on nanoscale molecular level is a pioneer study to improve or modify wood. In this paper, for the first time, the technology way to compound wood and MMT on nanoscale is systematically put forward. First, Na-transformation and organic modification of Ca-MMT are comprehensively studied and organic MMT is successfully obtained. Second, Water-soluble PF/MMT intercalation nanocomposite is prepared. Then with PF as compounding intermediate wood/MMT intercalation nanocomposite is prepared. This exploring research provides a new idea to modify wood and a new approach to prepare wood/inorganic composite.In this study, calcium cations (Ca2+) in Ca-MMT are first exchanged with sodium cations (Na+) which are easier to be substituted by organic cations; and the hydrophilic Na-MMT is modified by organic reagent to be hydrophobic and be compatible with polymer; then by virtue of water-soluble phenol formaldehyde (PF) resin wood and MMT are compounded on nanoscale through vacuum-impregnation. In this way wood/MMTintercalation nanocomposite (WMNC) is prepared. With the analyses of scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer-differential thermal analyzer (TG-DTA) and other measures, the following results are obtained.(1) With Na+ substituted for Ca2+, the swell capacity, swell value and cation-exchange capacity (CEC) of MMT are greatly improved. Compared with Ca-MMT, Na-MMT has bigger interlayer distance (JooiX lower crystallinity, better colloid properties and higher activity. The optimum parameters to transform Ca-MMT into Na-MMT are: MMT dispersion concentration in water, 15%; the addition amount of sodium carbonate, 4%; reaction temperature, 60 C; reaction time Ih.(2) The organic modification of MMT has great effect on the preparation of MMT nanocomposite. The interlayer distance of organic MMT (OMMT) is remarkably enlarged, and some MMT sheets exfoliate to be single nanolayers and disperse freely. The hydrophilic layer surface is modified to be organophilic. The thermal-stability of OMMT is greatly improved. So the organic modification of MMT in this study is very successful. The optimum technology is: organic intercalation agent, CIS; MMT grain granularity, 200 mesh; aged time in water, 24h; MMT dispersion concentration in water, 5%; intercalation agent concentration, 0.3mol/L; intercalation agent amount, exceeding 50% CEC; the pH value of medium, 4; proton donor, vitriol (H2SO4); reaction temperature, 80 C; reaction time, 1.5-2h; vacuum-drying; drying temperature, <120 C; moisture content, l%-3%. The main factors in an order of influence are: addition amount of intercalation agent > MMT water dispersion concentration > reaction time > the acidity or alkalinity of medium (pH value) > reaction temperature.(3) The organically modified MMT has good compatibility with self-synthesized water-soluble PF resin. Partially intercalated and partially exfoliated PF/MMT nanocomposites (PMNC) are easy obtained. PF compounded with OMMT has improved thermal properties. There may be some strong linking effect between MMT and PF which is relative to oxygen atom. If phenol, formaldehyde and OMMT are compoundedsimultaneously, it is called one-step method. One-step way is affected by many factors and the reaction is very complicated, so its investigation is very difficult. If the PF resin is synthesized in advance befo更多还原