木材的塑化技术及应用

木材塑化改性,可使木材转化为热塑性材料,并使木材性能得到改善。改性产物可以代替部分石油制品或用于人造板生产,有利于木材加工剩余物的充分利用,扩大木材的加工利用途径。本文总结木材主要塑化方法,如酯化、醚化的研究及应用现状,塑化产物的性能及用途,指出现存的主要问题,探讨今后木材塑化的发展方向。     

化学转化木材为热塑性材料

木材是不溶不熔的材料。近年来研究发现通过适当的化学改性反应特别是经典的纤维素酯化和醚化反应对木材进行化学改性，可使木材转化为可溶可熔的新型热塑性高分子材料。这些热塑性木材可单独或与合成高聚物共混热压加工成型为各种形状的类塑料产品，或利用其热熔性制造自粘合型纤维板、微粒板或木板材。这些新发现为扩大木材的加工方法、劣废木材资源更有效的综合利用及提高木材的应用价值开辟了全新的途径，故已成为近１０多年来木材综合利用新技术研究开发的热点之一。本文综述了该领域的研究开发现状。     

木塑共混复合材料

木塑共混复合材料(以下简称木塑材料)是近年来发展起来的一种新型材料,用木纤维或植物纤维填充、增强的改性热塑性材料,兼有木材和塑料的性能和特点,经挤出或压制成型为型材、板材或其他制品,可以替代木材和塑料,并且可以百分之百回收再生,是真正意义上的“绿色”工业制品,也是一种理想的木材替代材料。WPC对于扩大木材的应用领域、开拓植物纤维利用的新途径、减少我国木材的进口量等具有重要意义。木塑材料将两种不同材料的优点有机地结合在一起,它既可以像木材一样表面胶合、油漆,也可进行钉、钻、刨等,同时又可像热塑性塑料一样成型加…     

木材液化的发展现状及研究前景

1 木材液化的方法 1.1 化学改性后液化法 木材化学改性主要是为了引入取代基,增加木材组织内的自由空间,加上改性反应过程中木素网络结构的断裂,引起木材体积的溶胀,降低木材组分分子间的相互作用力,降低了液化温度.木材化学改性方法包括烷基化、酰化、酯化或醚化等.依据化学处理木材不同的特性,其可在中性水、有机溶剂或者有机溶液中液化,并由此制备新的高分子材料.     

基于黏结剂喷射的木质材料增材制造技术研究进展

木材是自然界中分布最广泛的材料之一,在制造业和建筑业等领域有着广泛的应用。我国是木材消费和木材加工剩余物产出大国,但目前国内木材加工剩余物利用率较低、利用方式单一,与发达国家相比差距较大。通过创新木材剩余物处理方式,研发相关技术,可逐步缩小与发达国家之间的差距。黏结剂喷射（3DP）技术具有材料来源广泛、加工简单、成型效率高等特点,基于木质材料特点,以木材加工剩余物为原料,实现木质材料增材制造具有广阔的发展前景。文中以增材制造中的木质纤维及其分类为背景,介绍增材制造中木质耗材的研究现状,重点阐述木质材料3DP中典型黏结剂喷射成型（BJ）技术、散装材料选择性沉积技术和单层制造（ILF）技术等3类技术的成型原理、研究进展及其最新应用等,根据木质材料的物理特性和成型机理,探讨黏结剂、粉末床工艺和后处理等因素对木质材料3DP成型精度和成型质量的影响,并对木质材料3DP技术存在的问题进行分析并展望其发展趋势。     

如何软化处理木材

木材是一种弹性——塑性材料．但木材的结构和性质又决定了木材是一种缺乏塑性的材料。所以木材的加工成型方法主要为切削和胶合，而不宜于采取弯曲或模压等塑性加工。所谓木材软化处理是使木材具有暂时的塑性，以便对禾材进行弯曲、压缩等塑料加工-，并在保持变形状态下干燥木材，以恢复木材原有的刚度和强度。     

基于材料加工特性的家具设计研究

运用比较分析法、调查法等科学研究方法,对木材、竹材、金属、塑料4种材料的成型加工特性、连接工艺特性、表面处理特性进行了整合,对比了4种材料加工特性的优劣势,分析了4种材料加工特性在家具设计中的运用,最终验证了掌握材料加工特性是实现家具产品造型理想效果的前提与保障,为利用材料加工特性进行家具设计提供参考。     

团结奋斗,繁荣木材工业科学技术——发刊词

木材是一种传统的材料,它具有重量轻、强度高、弹性好、纹理美观、色调丰富、纤维含量高、加工容易等优点,迄今世界各国都把木材列为重要的工业原材料。木材加工是以木材和木质材料为原料,经机械和(或)化学方法加工处理,其制成产品仍保有木材基本特性的加工过程。它在森林工业中与林产化学加工同为木材采伐运     

木粉塑料化改性研究

本研究的目的是对木材进行脂化、醚化改性,以改善木材与塑料的相容性.采用氯化苄、邻苯二甲酸酐和马来酸酐对木粉进行改性,探讨了改性后木粉的微观结构、表面基团和热塑性.结果表明,3种改性剂都增加了改性后木粉的热塑性,其中氯化苄改性的木粉热塑性最好,能实现自身粘合并呈塑料化倾向.     

碎料模压家具的特点

碎料模压成型家具是采用木材碎料搅拌入一定量的胶黏剂模压而成的。通常先压成零部件,再运用各种联接件组装成产品。由于所用的原材料是采伐或木材加工下来的剩余物,再经过粉碎成木片、刨花等碎料,所以可以在不增加或少增加木材数量的情况下,生产出质量优良的家具,充分利用了木材加工下来的废料,因而,碎料模压家具也是木材综合利用的一个     

Properties of wood plasticization with octanoyl chloride in a solvent-free system

Diffuse reflectance Fourier transform infrared spectroscopy (DRIFT), solid state cross-polarization/magic-angle-spinning ¹³C-nuclei magnetic resonance spectroscopy (CP/MAS ¹³C-NMR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA) were used in this study to elucidate the characteristics of wood sawdust after esterification. Results revealed that thermoplastic wood was produced by solvent-free esterification using octanoyl chloride. Increasing the duration of treatment enhanced the extent of esterification. After octanoylation, the crystallinity of wood sawdust was decreased, whereas thermoplasticity, hydrophobicity, and thermal stability were enhanced. The complete flow of the octanoylated wood meal was achieved at around 300°C under a force of 0.01 N, indicating that octanoylated wood sawdust is a good thermoplastic material.     

木材耐久性超疏水表面构建研究进展

木材作为一种天然可再生材料,富含亲水性基团且孔隙结构发达,因而具有很强的吸湿/水能力,易发生变形、开裂、腐朽等问题。基于“荷叶效应”原理,仿生构建木材超疏水表面是有效隔离木材与水分接触,赋予木材防水、防污、自清洁等优良特性的木材功能性改良新途径。然而超疏水木材在实际应用中不可避免地要受到刮擦磨损、阳光辐射、化学腐蚀等外界因素的影响,容易造成表面微/纳米粗糙结构的破坏或低表面能物质的降解,从而导致超疏水性能的降低或丧失,限制了超疏水木材的实际应用,因此设法提高木材表面超疏水涂层的机械稳定性和耐久性是亟待解决的关键问题。笔者首先分析了木材超疏水表面耐久性差的主要原因,介绍了木材超疏水表面耐久性能的测试方法,重点综述了木材耐久性超疏水表面的构建策略及其最新研究进展,最后对超疏水木材研究中存在的一些问题及发展趋势进行了总结和展望。     

木质材料激光表面处理研究进展

激光以其能量密度高、运行轨迹自如、方向性好等优点,被广泛用于木质材料切削加工以及表面处理等领域.其中,木质材料激光表面处理,即利用激光热/光电子效应促进材料发生物理、化学变化,以实现改性的目的.笔者对木质材料激光表面处理原理、激光类型与用途以及激光表面处理技术特点与应用领域等内容的研究现状进行了综述与分析.现有研究表明...     

Thermally initiated solvent-free radical modification of beech (Fagus sylvatica) wood

A procedure for rapidly modifying beech wood using a thermally initiated solvent-free grafting system was examined. In the modification, butyl acrylate and butyl methacrylate were used as vinyl monomers. Free radicals were generated from 2,2′-azobis(2-methylpropionitrile) or benzoyl peroxide at 103 and 180 °C by contact heating of the modified material. Chemical changes in the material were investigated by FTIR and X-ray photoelectron spectroscopies. The modification resulted in decreased surface wetting of the material manifested by increased water contact angles. The hardness of the resultant material decreased, while its color changed by the effect of temperature. It was shown that the approach allowed for efficient thermal-initiated modification of wood with rapid contact heating.     

Crash simulation of wood and composite wood for future automotive engineering

ABSTRACT

Multi material mix is a promising approach to reduce weight and the carbon footprint in automotive engineering at competitive costs. As a result, automotive industry is getting more venturous, exploring and applying other materials than metals and plastics – e.g. fibre reinforced plastics (FRPs). In this context, engineered wood products (EWPs) and wood composites should be considered: Wood composites provide high stiffness, strength, excellent damping, high resistance against fatigue and a very low density at low material costs. It is hypothesized that modern wood composites are competitive to metals and artificial fibre-reinforced materials when designed and applied properly. The application of wood and wood composites in automotive engineering calls for precise and reliable material data, required for initial material selection and later in numerical simulation. In this study, a material model normally used for modelling FRPs was adopted. A material database was generated for three hardwood species, to establish the required material parameters and validate material model. Results prove that wooden components can be simulated in crash situations and the selected material model is applicable, even in full vehicle simulation.     

Effect of adding steam-exploded wood flour to thermoplastic polymer/wood composite

The effect of steam-exploded wood flour (SE) added to wood flour/plastic composite was examined using SE from beech, Japanese cedar, and red meranti and three kinds of thermoplastic polymer: polymethylmethacrylate, polyvinyl chloride, and polystyrene. Addition of SE increased the fracture strength and water resistance of the composite board to an extent dependent on the polymer species and the composition of wood/SE/polymer. However, water resistance decreased with the increasing proportion of SE when SE meranti was added. Effects of the wood species of SE on the properties of resulting board were small. An increased moisture content of wood flour or SE (or both) increased the variation of board performance.     

The glass transition of wood from the viewpoint of mechanical pulping

Summary Familiarity with the mechanical and thermal processes in the mechanical defibering of wood is a prerequisite for an understanding of mechanical pulping methods. The thermal softening behaviour of wood components, which can be described by glass transitions, is of particular significance. Investigations on the thermoplastic behaviour of solid wood confirm that the thermal softening of wood occurs at 115–145°C. The thermal softening behaviour is largely dependent on wood moisture but also on the nature of the wood. The results obtained permit conclusions regarding the layout of technological processes in groundwood.     

Wood-polymer combinations: The chemical modification of wood by alkoxysilane coupling agents

Summary Vinyl polymers in wood-polymer combinations fill cell cavities but do not bond to nor enter cell walls to any noticeable extent. The wood dimensional stability thus remains virtually unchanged. Nonleachable-bulking treatments which react with the cell wall material tend to diminish wood strength properties and do not appear to show promise for providing a link between the cell wall and the polymer. Alkoxysilane coupling agents are widely used to modify the interface between dissimilar materials, such as glass fibers and thermoplastic or thermosetting resins. The coupling agent -methacryloxypropyltrimethoxysilane was used in this study with trembling aspen, white birch and eastern white pine woods. Antishrink efficiencies comparable to those reported for reactive chemical wood modifiers were obtained. This treatment did not require acidic or basic reaction conditions which could cause wood strength reductions. Its effects upon wood strength and the extent of bonding to the cell wall are presently under investigation.The authors are grateful for financial support by the Natural Sciences and Engineering Research Council of Canada     

环氧树脂/木质碎料复合材料力学性能

以环氧树脂为胶结材料、不同类型的砂和木质碎料作为集料,利用平板振捣器,采用振实法制备了树脂基木质碎料复合材料.分析环氧树脂用量、木质碎料用量以及砂类型对树脂基木质碎料复合材料的抗折、抗压强度的影响规律.结果表明:试件的最大抗压、抗折强度分别可达5.74和17.16 MPa;在相同胶集比下,试件强度随着木质碎料掺入量的增...