共查询到18条相似文献，搜索用时 171 毫秒
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热塑性复合材料是一种新型复合材料,具备密度低、强度高、可回收、成本低等优势。近年来,热塑性复合材料在我国取得了快速发展,已逐渐成为工程塑料较好的替代品。介绍了热塑性复合材料基本分类、热塑性复合材料加工技术、热塑性复合材料应用范围,同时提出了热塑性复合材料增强木质材料的措施,为热塑性复合材料运用及进一步研究提供参考。 相似文献
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等离子体改性技术作为一种高效、绿色的处理工艺已广泛应用于催化剂合成、表面活化、化合物镀膜等研究及应用领域。其对木质材料改性研究从上世纪90年代至今已取得许多重要的实验及理论成果,可综述为:1）木质材料等离子体改性的特性; 2）木质材料等离子体改性的机理; 3）等离子体改性木质材料的设备及工艺。文中在整理近年文献资料的基础上分析了文献中相互矛盾的结论,并对未来等离子体改性木质材料的研究方向提出建议。 相似文献
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木塑复合材料(WPC)是一种兼具有木材和塑料双重优点的新型复合材料,在建筑、家具、装饰、运输和汽车内衬等领域显示出独特的优势并得到了迅速发展。为了进一步降低成本和增强木质感,商业化WPC产品的木质纤维填充量在40%～60%,甚至超过70%。这种高的木质纤维填充量造成了WPC挤出加工困难,主要表现为不稳定流动及表面撕裂等现象的出现,由此导致产品质量差,加工效率低。目前,人们对这种高填充体系下WPC熔体的流变行为尚不完全理解,更是缺乏系统的理论基础。高填充体系下WPC熔体中木质纤维材料与木质纤维材料之间、木质纤维材料与聚合物基体之间相互作用增强,其中木质纤维材料(种类、尺寸、填充量)、聚合物基体的分子质量和分子质量分布、润滑剂、偶联剂都是该复杂体系流变行为的重要影响因素。本文对高木质纤维填充体系下WPC的流变行为研究进行系统回顾,以期为WPC的配方设计、工艺控制、加工设备升级和模具制造提供一定的理论基础和科学依据。 相似文献
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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:材料对于不同波长激光的吸收系数差异明显,基于此特性可实现木质材料表层激光选择性消融,以满足不同应用场合的加工需求;其次,激光功率、激光扫描路径密度以及进给速度等激光工艺参数,决定了表面处理过程中能量密度及分布,进而影响木质材料表面改性强度与深度,通过对激光参数的优化可实现木质材料表面部分性能(如表面颜色、润湿性、功能性结构等)的精准改性。最后,还探讨了木质材料激光表面处理领域研究现状与趋势,阐明了研究的科学意义和未来研究方向,以期为创新木质材料表面处理技术、实现其提质增效提供理论指导,也为拓宽激光技术在木质材料加工领域的应用范围提供思路。 相似文献
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Catarina Pereira Fernando Caldeira Jorge Mark Irle José Maria Ferreira 《Journal of Wood Science》2006,52(4):318-324
It is already known by the scientific and industrial communities that lignocellulosic substrates are, to a certain extent,
inhibitors of the hydration reaction of cement. The extent to which and how they influence such reactions is still a matter
of debate. Several techniques, such as calorimetry, i.e., the measurement of the heat evolved or obtaining temperature profiles
during the hydration, the determination of extractive contents of lignocellulosic substrates and their relation with the characteristics
of the hydration curves, or even testing of the mechanical properties of the wood-cement composites, have been used in previous
research. This study complements past research using two techniques that have been used in the analysis of cement hydration
but are not usually applied to lignocellulose-cement mixes, namely X-ray diffraction (XRD) and differential thermal analysis
(DTA). The raw materials for this study were three lignocellulosic materials of Portuguese origin: cork (the bark of Quercus suber L.), blue gum (Eucalyptus globulus Labill.), and maritime pine (Pinus pinaster Ait); and Portland cement. The two techniques allowed tracking of the evolution of the main cement constituents during hydration.
It was found that all the lignocellulosic substrates had detrimental effects on cement hydration. The blue gum exhibited the
fastest hydration kinetics in the initial stage of reaction, but was then overtaken by cork, which at the end gave the highest
hydration conversion amongst the three lignocellulosic substrates. Although pine caused the slowest initial hydration kinetics,
with the passage of time its effect approached that of blue gum. At the end of the hydration period, specimens containing
either species had similar quantities of hydration reaction products. The DTA and XRD results were consistent and are in good
agreement with the temperature profiles and compatibility indexes reported in a previous work. 相似文献
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天然木材制备的木材海绵可替代硅胶海绵、聚氨酯和三聚氰胺等合成高分子基海绵,作为高效吸油剂用于污水净化,并衍生出一系列运用。在去除木质素和半纤维素后,天然木质材料保留了原生的精巧三维分级孔隙结构,从木材直接转化为生物基纤维素骨架,具备高孔隙率、比表面积大、优异机械性能等特性的同时,还保留了木材生物相容性等特点。对木质纤维素骨架进一步改性后得到的木材海绵,在油水分离、能源存储、传感器、穿戴设备等领域具备一定的发展潜力。文中综述目前制备木材海绵的有效方法,包括精巧分级孔隙率的木质纤维素骨架制备和基于该木质纤维素骨架的各类功能性材料开发探索;针对木材海绵的高效制备和功能化,从基础物质、基本性能与工艺流程角度梳理近5年的相关工作,以启发该类先进材料的创制思路;同时,探讨木材海绵功能的先进性,并对其应用前景进行展望。 相似文献
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γ-戊内酯是以木质纤维素生物质为原料制备的一种潜力巨大的平台化合物,它既可转化为高密度燃料、相关高分子材料以及其他高价值化学品,也可作为绿色溶剂促进木质生物质向其他高值方向转化。在化石能源日益紧俏、环境问题日益严重的今天,对γ-戊内酯进行深入研究显得尤为重要。但在实际生产中,仍存在产量低、除杂难等经济环保类问题需要解决。基于γ-戊内酯研究的最新进展,从γ-戊内酯的制备与应用两方面进行了论述,综述了生物质催化生产γ-戊内酯的研究进展,说明不同底物生产γ-戊内酯的理论基础与优缺点,并以贵金属和非贵金属催化剂为界,分类讨论了多种用于合成γ-戊内酯的催化剂。最后,结合γ-戊内酯在纤维素生物质转化应用方面的进展情况,探索了γ-戊内酯与其他相关有机物之间的制备关系,为γ-戊内酯的进一步开发利用提供了思路。 相似文献
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Dr. Eiichi Maekawa 《Wood Science and Technology》1996,30(2):133-139
Summary In order to aim at a proved pretreatment for the enzymatic saccharification of lignocellulosic materials, the combined effect of the steam explosion treatment and the newly added alkali-hydrogen peroxide treatment was investigated. As a result, the following findings were obtained from comparison of the saccharification ratio (%) among the materials used: 1) Marked differences based on the lignocellulosic species characteristic of biological materials were observed. 2) Lignocellulosic samples such as rice straw, poplar, and maple chips gave enzymatic saccharification ratio (%) close to 100% by using the samples obtained after extraction with various solvents without alkali-hydrogen peroxide treatment. 3) Chip samples such as Japanese larch, loblolly pine, and Japanese cypress gave the very low enzymatic saccharification ratio (%) of 20–40% after the steam explosion and extraction with various solvents. 4) In comparison with enzymatic saccharification ratio (%) of original samples treated with steam explosion, alkali-hydrogen peroxide treatment resulted in greater effect based on the treatment of 2–2.5 times. 5) Alkali-hydrogen peroxide treatment afforded remarkable effects based on the treatment of the softwoods, such as Japanese larch and loblolly pine.The author is indebted to Professor Mitsuhiko Tanahashi, Faculty of Agriculture, Gifu University, for assistance on preparation of various lignocellulosic samples using a steam explosion equipment. The investigation was supported by the grant-in-aid for scientific research of the Ministry of Education in Japan 相似文献
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乐器共鸣板用木材声学振动性能改良研究现状及趋势 总被引：1，自引：0，他引：1
木材是制作乐器共鸣板的重要材料, 木材的声学性能在很大程度上决定了乐器的声学品质。文中在分析乐器板用木材声学振动性能改良的着手点与切入点的基础上, 总结木材声学振动性能改良方面的研究进展, 认为以下几个方面将成为未来研究的热点:1)从弹性模量、比弹性模量、声辐射品质常数和声阻抗等指标出发进行木材声学性能功能性改良研究; 2)开展乐器共鸣板用木材的替代树种用材的功能性改良研究, 扩大可用于制作乐器共鸣板的资源范围; 3)从改善木材声学振动效率和振动音色角度进行木材功能性改良的研究; 4)开展新型的乐器共鸣板用材研究。 相似文献
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