【作者】 薛振华；

【导师】 赵广杰；

【作者基本信息】 北京林业大学 ， 木材科学与技术， 2006， 博士

【摘要】 为了探明蒙脱土(MMT)/木材复合材料(WMC)的构造以及WMC中木材与蒙脱土在分子水平上的相互作用,本研究利用不同方法对木材进行了预处理来改善木材的渗透性,进而以酚醛树脂中间介质制备了蒙脱土/木材复合材料(WMC)。使用X射线衍射仪(XRD)、应力松弛仪、阻抗分析仪、动态热机械分析仪(DMA)、热重-差热分析仪(TG-DTA)、差示分析仪(DSC)等分析手段,测定了WMC结晶区域的衍射谱、静态应力松弛谱、动态介电松弛谱、动态热机械松弛谱以及热稳定性。计算了WMC结晶区域的相关参数,WMC介电松弛的动力学和热力学参数、热机械松弛的表观活化能以及WMC形成和热分解的动力学参数等物理量,并依据这些物理量研究了木材-蒙脱土复合材料(WMC)的结晶构造,以及WMC中木材与蒙脱土在分子水平上的相互作用机理。通过上述研究得到以下主要结论:(1)木材经氢氧化钠(NaOH)、微波(MW)、氢氧化钠/微波(NaOH/MW)、氢氧化钠/超声波(NaOH/US)处理后,衍射峰强度下降,密度下降。超声波(US)处理后木材的衍射峰强度增大,结晶区域密度增大。(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。有机分子链越长,层间距越大,同时带有支链的有机分子对蒙脱土的层间距也有较明显的影响。超声波分散对蒙脱土层间距的扩展更显著。从形成复合材料的相对结晶度与处理材比较来看,木材经超声波处理后与蒙脱土形成的复合材料中,蒙脱土以剥离型存在,其他处理形成的复合材料中主要以插层结构存在木材中。不同有机蒙脱土形成的复合材料,与木材相比结晶构造没有变化,但相对结晶度降低。(3)木材经超声波(US)、微波(MW)处理后相对应力松弛量减小,而经氢氧化钠(NaOH)、氢氧化钠/微波(NaOH/MW)、氢氧化钠/超声波(NaOH/US)处理后相对应力松弛量明显增大;木材-蒙脱土复合材料(WMC)的抗应力松弛性能明显增强,不同预处理试材形成的复合材料的应力松弛性能相近;WMC的应力松弛对温度非常敏感,随温度升高,松弛速率明显加快,但氢氧化钠/超声波(NaOH/US)处理试样形成的复合材料却在相对高温区域表现出较强的抗松弛能力。(4)蒙脱土/木材复合材料(WMC)的介电弛豫强度约为木材的2/3,酚醛树脂/木材复合材料(WPC)的介电弛豫强度约为木材一半;不同的固化工艺条件下形成复合材料的介电弛豫强度略有差异,常规固化、真空固化、微波固化形成复合材料的弛豫强度依次降低;蒙脱土含量不同,对复合材料的介电弛豫也有更多还原

【Abstract】 In order to clarify structure of montmorillonite(MMT)/wood composite (WMC) and the interaction between wood and MMT at a molecular level, in this research, wood samples were firstly pretreated by different ways to increase penetrability, and afterwards WMC was compounded by medium of phenol formaldehyde resin (PF), then microstructure and some physical properties, such as crystallinity, stress relaxation, dielectric relaxation, viscoelastic properties, thermal stability and so on, were analyzed and some parameters, such as crystal parameters of WMC, thermodynamic quantities of static stress relaxation and thermodynamic relaxation processes, dielectric parameters of dielectric relaxation, were calculated. Using these parameters, the crystal structure and of composite was reasearched, and mechanism of bonding between wood and MMT at moluculer was developed.These main research results achieved are as follows,(1) The X-ray diffraction intensity of wood, which were treated respectively by sodium hydroxide(NaOH),microwave(MW), sodium hydroxide / microwave (NaOH /MW) and sodium hydroxide / ultrasonic (NaOH/US), decreased and some linkages were broke in crystal regions and the crystal density in wood crystal regions decreased accordingly. However, it was opposite for ultrasonic treated wood.(2) The organic modification of MMT had a great effect on the preparation of WMC. After organic modification, the interval between MMT layers expanded evidently, and the longer the length of organic compound molecular chains, the lager the interval of layers. At the same time, the organic compounds with side chains had also an evident effect on the expanding of interval. According to the analysis on the crystalinity of composite and control wood, it was concluded that MMT was divided in MMT/wood with US pretreatment composite, and MMT exist within the composite with other pretreatments in the form of insert. The crystal structures of all composites prepared by using different organic MMT hardly changed, but the relative crystallinities decreased.(3) Relative stress relaxation of wood which was treated by US and MW is smaller than that of更多还原