木材液化技术的研究进展

综述了近30年来国内外木材液化技术的研究进展,简介了以酸或碱为催化剂、无催化剂和超临界萃取等木材液化的主要方法,木材液化技术对充分利用自然界中可再生资源、降低环境污染具有重要的意义.     

木材溶剂液化技术及其在制备高分子材料中的应用

木质材料经过热化学液化,可进一步制备酚醛树脂、聚氨酯等高分子材料。本文介绍了木材液化技术制备高分子材料的发展状况,包括液化方法、木材主成分的液化机理以及液化生成物的应用,指出在木材液化反应机理、液化产物的利用和最佳液化工艺的开发等方面尚有待进一步研究,并提出充分利用木材的生物降解性,开发木材液化物与其他材料复合的新型高分子材料具有广泛的前景。     

木材溶剂液化技术及其在制备高分子材料中的应用

木质材料经过热化学液化,可进一步制备酚醛树脂、聚氨酯等高分子材料.本文介绍了木材液化技术制备高分子材料的发展状况,包括液化方法、木材主成分的液化机理以及液化生成物的应用,指出在木材液化反应机理、液化产物的利用和最佳液化工艺的开发等方面尚有待进一步研究,并提出充分利用木材的生物降解性,开发木材液化物与其他材料复合的新型高分子材料具有广泛的前景.     

木材中的纳米分形木质纤维及碳素纤维材料的制备

利用分形理论构建了木材细胞壁中的分形木质纤维,并计算了分形木质纤维S1层和S2层的扭曲分形维数,指出木材中具有纳米尺度的纤维结构;同时,以木材液化和纳米纺丝技术为基础,提出了木材苯酚液化产物制备碳素纤维材料的构思和技术路线,为解决木材纳米、微米材料的制备提出了新思路。     

木材液化及其在高分子材料中的应用

木材通过液化可转化为具有反应活性的液态产物,进一步反应可以制备胶粘剂、聚氨酯材料等新型高分子材料。文章从方法、机理以及其产物在制备高分子材料等方面对木材液化的研究进展进行了评述。     

木材的超临界气化和液化与木本生物质能源转化

木材是生物质能源的主体,开发木质(生物质)能源也是我国木材工业一个重要内容。木材的超临界流体气化和液化是大规模利用木质生物能的有效途径,具有良好的经济前景和环保优势。介绍木材的超临界流体气化和液化的基本原理和研究进展,应用木材超临界热解和气化制氢,对生物质能源的开发和森林资源的高效利用具有重要意义。     

木质生物材料多元醇液化及其在聚氨酯中的应用

液化技术是近年来生物质材料高效增值利用领域的研究热点,用多元醇等有机溶剂能将难溶、难熔的木质生物材料转化为可流动、具有反应活性的液态物质,拓宽了木材的应用领域。液化产物可作为合成高分子树脂的原料,能部分替代来源于石化产品的聚酯或聚醚多元醇。综述了木质材料多元醇的液化方法、液化机理及液化产物在聚氨酯中的应用。     

杉木液化产物用于胶粘剂制备的研究

研究用少量的苯酚液化木材及其产物用于胶粘剂制备的方法,在硫酸催化剂作用下,用苯酚液化杉木木粉,得到木材液化产物.在液化产物中加入适量的甲醛和氢氧化钠溶液制备热固性酚醛树脂.压板测试结果表明,由木材液化产物所得树脂的干状胶合强度令人满意,但经蒸汽循环试验后,湿状胶合强度尚达不到JAS标准的要求,在下阶段工作中,需进一步研究木材液化产物胶粘剂的改性以提高其胶合耐久性.     

响应面分析法优化木材微波液化的工艺研究

以醇解的聚对苯二甲酸乙二酯(PET)饮料瓶为液化剂,甘油为辅助液化剂,微波辅助加热,用2.5%H2SO4催化液化木材。采用Design-Expert7.1软件对木粉微波液化试验进行了方案设计和试验结果分析。选取液化温度、液化时间、液固比和微波辐射加热功率等四个因素进行中心组合设计;运用响应面法对木材微波液化工艺参数进行优化,得到了综合液化率与试验影响因素之间的定量数学关系模型,以及各个单因素和交互作用对液化率的影响结果,给出了木粉液化率的残差分布以及不同操作变量之间的综合液化率等值线和三维关系。木粉的微波液化实验最优条件为:反应时间10.51min,液固质量比3.93,液化温度154.7℃,微波辅助加热功率3.71kW,该条件下能使木粉完全液化。     

木材加工用耐水性苯酚液化树皮-甲醛胶粘剂的研制

树皮是一种来源丰富可再生的天然高分子材料。本文采用高温苯酚液化的方法,在复合酸存在下将落叶松全树皮液化成为木材胶粘剂的原料。研究了树皮液化产物制备木材胶粘剂的合成工艺,特别是碱用量对苯酚液化落叶松全树皮一甲醛胶粘剂各主要性能的影响。结果表明,增加碱用量会缩短树皮胶的贮存期,但可降低胶中的游离甲醛;通过降低树皮胶合成时的终点黏度,并在合成末期用水稀释,可有效提高树皮胶的适用期,并可确保树皮胶具有很好的胶接强度和耐水性、较快的固化速率以及很低的游离甲醛释放量。     

木质生物质的液化及其产物的高效利用研究进展

对国内外木质生物质原料的液化及液化产物的高效利用研究的现状及进展进行了概述,讨论了木质生物质原料液化及其产物的应用前景,重点讨论了不同木质生物质原料液化过程中的主要影响因素,并分析了具有代表性的液化物结构特点,具体介绍了一些液化产物实际应用特别是在胶黏剂制备方面应用的典型实例。对我国该领域研究存在的问题、产业化发展提出了一些看法。     

A KINETIC STUDY OF SULFURIC ACID-CATALYZED LIQUEFACTION OF WOOD INTO PHENOL

The powders of monarch birch wood (Betula maximowiczina Regel) were liquefied into phenol using sulfuric acid as a catalyst at various temperatures and reaction times. Typical kinetic parameters of the degrading reaction of wood in the presence of phenol and the acid were determined using typical kinetic models. In addition, the activation parameters of the liquefaction of wood were determined according to transition-state theory. The results of showed percent liquefied wood that about 100% of the wood could be liquefied into phenol at a temperature of 150°C for about 2 h. However, about 68% of phenol was found to react mainly with wood components along with sulfuric acid and phenol itself. The kinetic studies showed that the liquefaction of wood into phenol using sulfuric acid obeyed a bimolecular type second-order reaction and Arrhenius law. The activation energy of the liquefaction was 68.5 kJ mol^-1. Furthermore, the findings related with activation enthalpy showed that the liquefaction of wood possessed a primarily endothermic reaction nature.     

A new pulverized biomass utilization technology

Pulverized wood biomass utilization technologies, such as gasification and liquefaction, were discussed. Firstly, pulverization technique of wood biomass by a vibration mill was introduced, and pulverized wood biomass characteristics were evaluated. The wood powder pulverized by the vibration mill had a round shape, and the wood fibers were completely broken. Therefore, the diameter of wood powder was fine and the crystallinity of cellulose was very low. By using this pulverized wood biomass, high temperature gasification experiment and liquefaction experiment were conducted. Gasification experiment was conducted in an entrained down flow gasifire. Since fine wood powder had a high reactivity, the gasification experiment showed the high gasification performance without a tar generation. Liquefaction experiment of wood biomass was conducted in a hot compressed water to produce saccharine. Pulverized wood biomass was also used as a raw material in the liquefaction experiment. By using very fine wood powder, productivity of saccharine increased dramatically.     

A KINETIC STUDY OF SULFURIC ACID-CATALYZED LIQUEFACTION OF WOOD INTO PHENOL

The powders of monarch birch wood (Betula maximowiczina Regel) were liquefied into phenol using sulfuric acid as a catalyst at various temperatures and reaction times. Typical kinetic parameters of the degrading reaction of wood in the presence of phenol and the acid were determined using typical kinetic models. In addition, the activation parameters of the liquefaction of wood were determined according to transition-state theory. The results of showed percent liquefied wood that about 100% of the wood could be liquefied into phenol at a temperature of 150°C for about 2 h. However, about 68% of phenol was found to react mainly with wood components along with sulfuric acid and phenol itself. The kinetic studies showed that the liquefaction of wood into phenol using sulfuric acid obeyed a bimolecular type second-order reaction and Arrhenius law. The activation energy of the liquefaction was 68.5 kJ mol^?1. Furthermore, the findings related with activation enthalpy showed that the liquefaction of wood possessed a primarily endothermic reaction nature.     

白蜡枝桠材在四氢萘与苯酚混合供氢溶剂中的液化工艺

通过正交试验考察了白蜡枝桠材在四氢萘与苯酚混合供氢溶剂中液化过程的5个因素对残渣率的影响。白蜡枝桠材在供氢溶剂中的优化工艺为：反应温度为150℃、时间为2．5h、木酚比为1：6、催化剂H2S04用量为6．5％、四氢萘用量为20％,在此工艺条件下,液化效率可以达到96％左右。各因素的影响次序为：时间〉温度〉木酚比和催化剂用量〉四氢萘用量。在选择的实验参数范围内,时间、木酚比和四氢萘用量越大时,白蜡枝桠材的液化残渣率越小,即液化效率越高。     

白蜡枝桠材在四氢萘与苯酚混合 供氢溶剂中的液化工艺

通过正交试验考察了白蜡枝桠材在四氢萘与苯酚混合供氢溶剂中液化过程的5个因素对残渣率的影响。白蜡枝桠材在供氢溶剂中的优化工艺为:反应温度为150℃、时间为2.5 h、木酚比为1:6、催化剂H₂SO₄用量为6.5%、四氢萘用量为20%,在此工艺条件下,液化效率可以达到96%左右。各因素的影响次序为:时间>温度>木酚比和催化剂用量>四氢萘用量。在选择的实验参数范围内,时间、木酚比和四氢萘用量越大时,白蜡枝桠材的液化残渣率越小,即液化效率越高。