Mechanical Properties of Uni-Directional Long Bamboo Fiber/Bamboo Powder Composite Materials

This paper describes the mechanical properties of the composite materials produced using long bamboo fiber and bamboo powder. Bamboo fiber and powder can be hot press-molded much like plastic materials, and the use of these materials in place of plastic products would reduce the environmental impact of extensive plastic use. In this study, the tensile and flexural properties of molded uni-directional long fiber reinforced composites made from bamboo fiber bundles and Bamboo powder were examined. The results showed that the tensile and flexural strength of bamboo fiber/powder composites were increased with increasing fiber content. On the other side, both strengths of composite were decreased with increasing molding temperature after 180℃. The highest tensile and flexural strengths of the bamboo fiber reinforced bamboo powder composites specimens which were tested were recorded at 169.9 MPa and 221.1 MPa, respectively.

Engineered Wood/Bamboo Laminated Composites for Outdoor Hydrophilic Platforms:Structural Design and Performance

Landscape designers increasingly prefer to use wood/bamboo-based composites for outdoor hydrophilic platforms owing to their natural surface texture,high performance,and sustainability to facilitate extensive interaction between people and water and enable the full range of ecological functions of water resources.In this study,four laminated composite(LC)structures were designed and manufactured using fluffed bamboo and wood veneers.Their surface textures,profile densities,water resistances,and mechanical properties were then evaluated.The type of fluffed veneer of the surface layer determined the texture of the LC surface.The specific structures of fluffed bamboo and wood veneer laminations were found to affect the LC profile density variability,water resistance,and mechanical properties owing to the differences in the strength and interfacial properties of bamboo and wood fibers.Finally,the water resistance and mechanical properties of all four LCs were found to be much higher than the highest level specified in GB/T 20241-2006 for“laminated veneer lumber”and GB/T 30364-2013 for“bamboo scrimber flooring”,indicating that they are promising materials for structures and flooring,particularly for outdoor hydrophilic platforms.

Development of a Composite Material Based on Wood Waste Stabilized with Recycled Expanded Polystyrene

Environmental pollution is a whole world concern. One of the causes of that pollution is the proliferation of plastic waste. Among these wastes there is expanded polystyrene (EPS), mainly from packaging. This study aims to valorize EPS waste by developing a composite material from EPS waste and wood waste. For this purpose, a resin made of EPS has been elaborated by dissolving EPS in acetone. That resin was used as a binder in volume proportions of 15%, 20%, 25% and 30% to stabilize the samples. Some of them were thermoformed. The method of elaboration was based on a device consisting of an extruder for mixing the constituents, and a manual press for shaping and compacting the samples. Analyses show that the drying time depends on the composition of the mixture. Increasing the resin content leads to reduce water absorption and porosity of the samples;it also contributes to homogenize the internal structure of the samples. However, for the same resin contents, the thermoformed samples are less porous;they have more homogeneous internal structure;and absorb less water than non-thermoformed samples.

Magnetic properties of NdFeB-coated rubberwood composites

Magnetic properties of composites prepared by coating lacquer containing neodymium iron boron （Nd-Fe-B） powders on rubberwood were characterized by vibrating sample magnetometry （VSM）, magnetic moment measurements, and attraction tests with an iron-core solenoid. The Nd-Fe-B powders were recycled from electronic wastes by the ball-milling technique. Varying the milling time from 20 to 300 min, the magnetic squareness and the coercive field of the Nd-Fe-B powders were at the minimum when the powders were milled for 130 rain. It followed that the coercive field of the magnetic wood composites was increased with the milling time increasing from 130 to 300 min. For the magnetic wood composites using Nd-Fe-B obtained from the same milling time, the magnetic squareness and the coercive field were rather insensitive to the variation of Nd-Fe-B concentration in coating lacquer from 0.43 to 1.00 g/cm3. By contrast, the magnetization and magnetic moment were increased with the Nd-Fe-B concentration increasing. Furthermore, the electrical current in the solenoid required for the attraction of the magnetic wood composites was exponentially reduced with the increase in the amount of Nd-Fe-B used in the coating.

Compressive failure of spruce wood rings reinforced with glass epoxy composite

We experimentally tested under radial compressive loads and statistically analyzed rings constructed from spruce wood and reinforced with glass fiber.We used the Weibull distribution in statistical analysis,and tested five types of rings including unreinforced and composite reinforced（CR） as wound around the ring,oriented as two layers at angles of 45°,60°,75° and 90° to the column axis.We calculated 95 % reliability of load carrying capacity of the rings by Weibull distribution.The highest load carrying capacity was obtained with CR rings at 60° to the axial axis of the ring.Load carrying capacities of rings at CR90,CR75,CR60 and CR45 were 137,192,215 and 126 %greater,respectively,than unreinforced rings.For unreinforced rings,failures resulted from catastrophic breaking of wood materials.None of the reinforced rings failed catastrophically because the outer surface of the rings was reinforced with glass–epoxy composite fiber.Cracks began at the core of the materials under the composite layer for all specimens and resulted in failure of the rings.

Wood/Cu复合材料的温压成形与表征

应用木材科学与技术、粉末冶金等交叉学科材料成形理论开发的木质粉末温压成形新技术,以芦苇秆(简称Wood)粉末为基材,在不添加任何可能造成环境污染的胶粘剂的前提下,制备的Wood/Cu复合材料的静曲强度、内结合强度分别高达85.55MPa、6.75MPa,磨耗量≤0.05g/100r、吸水率<0.50%,且具有韧性断裂特征;采用Wood/Cu复合材料制备的滑动轴承的压溃强度、表观硬度分别高达100MPa、50HB,可望用于替代粉末冶金烧结青铜生产轻载滑动轴承,从而在节约有色金属的同时,为农林木质剩余物的高质清洁利用开辟一条新途径。

Recent development and challenges in enhancing fire performance on wood and wood-based composites:A 10-year review from 2012 to 2021

Due to their durability,versatility,and aesthetic value,wood and wood-based composites are widely used as building materials.The fact that these materials are flammable,however,raises a major worry since they might cause fire hazards and significant loss of life and property.The article investigates the variables that affect fire performance as well as the various fire-retardant treatments and their mechanisms.The current developments and challenges in improving the fire performance of wood and wood-based composites treated with fire-retardant materials are summarized in this paper.Nanoparticles,organic chemicals,and densification are some recent developments in fire-retardant treatments that are also emphasized.Key points from the review are summarized,along with potential areas for further research and development.

Investigation of Wooden Beam Behaviors Reinforced with Fiber Reinforced Polymers

Wood material can be demolished over time due to different environmental factors.Structural elements may need to be strengthened over time as a result of possible natural disasters or during use.Beams are elements under load in the direction perpendicular to their axes.Therefore,they are basically under the effect of bending.When the studies on the behavior of beams against bending test are examined,it is known that the bottom surface of the material generally breaks.For this reason,fiber reinforced polymers(FRP)materials have been used in recent years to reinforce beam members.It is a scientific fact that it is necessary to prefer FRPs for the solution of this problem,as well as their properties such as lightness,corrosion and flexibility,their application without disrupting the appearance of wood.In this study,it was aimed to investigate the effect of reinforcing wooden beams with fiber reinforced polymer materials with different properties on different bending behaviors such as load bearing capacity,ductility,modulus of elasticity.It was observed that the ductility and bearing capacity of wooden beams reinforced with fiber reinforced polymer materials increased significantly compared to non-reinforced beams.

木塑复合材料在家具中的应用

木塑材料作为一种复合型材质具有较强的可塑性、较小的污染性,相较于塑料及实木材质优势明显,在家具制造领域的实用性逐渐增强。本文主要分析了木塑复合材料在家具中应用的原则与优势、设计方法以及应用实例,为木塑材料家具产品开发提供更多的思路与建议。

LVL结构调控及应用研究进展

在我国木材资源紧缺、人工林材质较差、而竹材资源较为丰富的背景下,单板层积材(Laminated Veneer Lumber,LVL)作为一种生物质工程材料,具备高效利用现有资源的优势,并且以其出色的力学性能可实现标准化、系列化生产,展现出广阔的应用前景。本文结合我国人造板产业的发展现况,概述了LVL的起源和发展,着重从复合材料力学性能的角度分析了LVL的结构特点,对单板分等和LVL组坯特点进行了介绍。同时,综述了酚醛树脂浸渍和纤维材料复合两种LVL增强方式。最后,对比讨论了国内外LVL的评价标准,并针对我国木结构建筑产业的发展现状和LVL应用过程中存在的问题,提出了若干建议。

矿物钢塑复合材料与木塑复合材料性能对比研究

对矿物钢塑复合材料板材与传统木塑复合材料进行系统表征,并对外观及微观结构、无机组成成分、热性能和力学性能等进行了对比分析研究。扫描电镜(SEM)结果表明,矿物钢塑复合材料板材的形状规则、无翘曲变形,样品断面较为密实,而木塑板材液氮脆断面存在界面剥离,易发生变形翘曲。红外光谱(FTIR)结果表明,三种板材的基体材料均为聚氯乙烯(PVC)树脂,其特征峰与PVC红外光谱类似。热重分析(TG和DTG)表明,木塑复合材料的热失重速率和质量损失率大于其余两种矿物钢塑,矿物钢塑的热稳定性较木塑复合材料得到了较大提升。随着铸造灰和钢渣的加入,复合材料的弯曲强度和模量均得到了提高,且经铸造灰填充的矿物钢塑力学性能为三者中最高,其弯曲强度和弯曲模量分别为33.0 MPa和4.72 GPa。矿物钢塑复合材料具有优异的热性能、力学性能,作为一种新型绿色环保材料,为我国大宗工业固废的高附加值回收提供一种新的解决方案。

竹集成材-SPF复合正交胶合木的研发及性能评估

运用相同工艺分别制备足尺垂直型竹集成材-SPF复合CLT(简称V-BWCLT)与足尺水平型竹集成材-SPF复合CLT(简称H-BWCLT)。依据国内外相关标准对两种BWCLT的胶层剪切强度、胶合耐久性、抗弯弹性模量(MOE)、抗弯强度(MOR)和层间剪切强度进行了测试,并用三维非接触式应变测量系统(DIC)对抗弯和层间抗剪试验过程中的受力变形情况进行记录。结果表明:在相同制备工艺条件下,两种BWCLT平均胶层剪切强度接近,浸渍剥离率均可达到相关标准要求。V-BWCLT的平均MOE与MOR分别为7941 MPa和56.7 MPa,而H-BWCLT的平均MOE与MOR分别为10144 MPa和54.0 MPa,H-BWCLT比V-BWCLT具有更高的弯曲刚度,但两者MOR较为接近。对比SPF-CLT,两种BWCLT的抗弯强重比均有显著提高,上述研究和分析为新型竹木复合CLT的实际工程应用提供了设计参考与理论依据。

锡铋合金/肉豆蔻酸制备具有金属外壳的储能木材

【目的】利用锡铋合金对肉豆蔻酸浸渍材进行热处理,在热的驱动下将锡铋合金引入木材内部,以解决木基相变储能材料面临的液体泄漏和导热性差问题。【方法】以浸渍了肉蔻豆酸的杨木为基材,通过高低温交替热处理将锡铋合金与基材结合,制备具有金属外壳的储能木材。利用扫描电镜、邵氏硬度计、万能力学试验机、导热系数仪、差式扫描量热仪对储能木材的微观形貌、端面硬度、顺纹抗压强度和热性能进行测试。【结果】在160~220℃热处理1~5 min下试样质量增长效果显著,力学性能与热性能随着热处理温度的上升与时间的延长而提升,顺纹抗压强度和端面硬度相较于未处理材分别提升了120.02%~149.59%、13.53%~46.93%,轴向、径向导热率分别提升了34.18%~165.67%、38.11%~80.70%。在190℃热处理5 min条件下锡铋合金的填充效果最佳,端面硬度、轴向、径向导热率达到最高值62.65 HD、0.5324和0.2987 W/(m·K)。木材内部肉豆蔻酸的留存率介于27.54%~63.68%之间,经过160℃热处理3 min后储能密度最高(59.38 J/cm3)。【结论】高低温交替热处理促使锡铋合金进入到木材的导管内,实现了不同程度的渗透。木材的三维孔隙结构与外层填充的锡铋合金解决了相变材料的液体泄漏及导热性差问题。制备的储能木材综合了木材、金属与相变材料的优势,具有更优异的端面硬度、顺纹抗压强度与热性能,有望应用于建筑墙体和储能地板等领域。

PLA/PPC/CS复合材料的制备工艺

通过在聚乳酸(PLA)/玉米秸秆(CS)复合材料中引入聚碳酸亚丙酯(PPC)改善韧性,使用熔融挤出与热压成型相结合的方式制备聚乳酸/聚碳酸亚丙酯/玉米秸秆(PLA/PPC/CS)复合材料,以热压时间、热压压力和热压温度为变量,以PLA/PPC/CS复合材料的冲击、弯曲和拉伸性能为评价指标设计单因素试验.试验结果表明,热压时间、热压压力、热压温度对PLA/PPC/CS复合材料的力学性能影响显著.最终优化出的热压工艺条件为热压时间10 min,热压压力7.5 MPa,热压温度190℃.

高填充油茶果壳基木塑复合材料的制备及力学性能

以油茶果壳和不同塑料即聚丙烯、高密度聚乙烯(PE-HD)、低密度聚乙烯、线性低密度聚乙烯为原料,采用模压成型的方法制备了高填充油茶果壳基木塑复合材料,利用电子万能试验机和悬臂梁冲击试验机测试其力学性能。通过单因素试验分析塑料种类对复合材料力学性能的影响,确定较优塑料种类后进一步优化制备参数。以壳粉含量、增容剂马来酸酐接枝聚乙烯(MAPE)含量、热压温度、热压时间为设计因素,以弯曲强度、弯曲弹性模量、拉伸强度、冲击强度为力学性能优化目标,设计L_(9)(3^(4))正交试验,研究了高填充油茶果壳基木塑复合材料的制备工艺,利用极差分析和方差分析得到了较优配方和工艺参数组合。研究表明:当添加塑料为PE-HD时,复合材料的弯曲强度最大为34.40 MPa,拉伸强度最大为18.20 MPa,力学性能较优;壳粉含量为65%时,添加7%MAPE的复合材料强度较好,弯曲强度最大为33.66 MPa;优化制备参数组合为壳粉含量55%,MAPE含量5%,热压温度160℃,热压时间10 min。

竹塑复合材料性能改良研究进展

竹塑复合材料是将竹纤维和聚合物基体合理复合制备的一种满足功能需求的生物质复合材料,具有广阔的应用前景。但竹纤维与聚合物之间的界面相容性差,导致其在应用中出现性能缺陷,解决该问题的关键在于改善二者之间的界面相容性。本文总结了四类可行的改善界面结合的措施以提高复合材料性能,包括竹粉改性处理、聚合物改性处理、中间相桥接和填充引入四方面,并阐述了不同的改性方法对复合材料性能的影响。

油茶果壳制备生物质复合材料的研究进展

通过高效提取、处理及使用天然生物质材料制备复合材料,是目前材料研发领域的重点研究内容之一。油茶果壳是油茶果的附属产物,每年会随着油茶果的收获有着大量的产出,其具有作为生物质复合材料原料的潜在价值。对油茶果壳材料进行了介绍,详细阐述了油茶果壳提取纤维素、直接制备木塑复合材料、制备生物质碳复合材料的相关研究及应用现状,以期为丰富油茶果壳材料高值化利用提供一定的指导。

木塑复合材料颜色调控研究现状及展望

随着木塑复合材料(WPCs)在市政园林、汽车和船舶制造等应用领域的快速拓展,市场对木塑制品外观颜色要求也逐渐多元化,颜色调控成为WPCs领域的研究热点,因此,研究WPCs颜色调控方法及其对WPCs性能的影响规律、分析WPCs颜色变化影响因素及揭示颜色调控机理具有重要意义。综述了目前WPCs颜色调控的研究进展,从制备原料、制备工艺和老化变色等方面对影响WPCs颜色变化的因素及及机理进行了梳理;分析了表面覆膜、制备复合表层和添加颜料等颜色调控的3种方法,并从颜色及表面形貌、力学和物理性能等方面分析了颜色调控对WPCs性能的影响,最后,结合WPCs颜色调控研究发展趋势以及未来研究工作重点进行了总结与展望。

CFRP布增强仿木柱轴压性能试验研究

为改善轴心受压仿木柱的力学性能,在其表面粘贴碳纤维增强复合材料(carbon fiber reinforced compo-site,CFRP)予以增强。考虑CFRP粘贴层数和方式的影响,在两端简支状态下对4组仿木柱试件进行了单调轴心受压试验,以了解其受力过程及破坏形态,得到了荷载-位移曲线和荷载-应变曲线。结果表明:粘贴CFRP布可以有效约束轴心受压柱中仿木材料的横向变形;与未增强的仿木柱相比,能有效地提高仿木柱的承载能力和延性,且改善的效果随着CFRP布粘贴量的增加而更为有效;CFRP粘贴量越大,对仿木材料的约束效应越强,仿木柱试件的峰值应力和极限应变越高。

防撞梁结构设计与碰撞性能研究

目的研究汽车防撞梁材料选择和结构设计对汽车安全性的影响。方法通过对汽车防撞梁的概念及特性进行总结归纳,并比对不同材料和不同结构的防撞梁对其安全性的影响,并通过仿真模拟探究不同材料下的碰撞性能。结果结构最优情况下,增强竹纤维复合材料防撞梁在其碰撞测试过程中表现出位移较低且修复性能较强等特性。结论该结果表明了增强竹纤维复合材料具有较好的保护性能,增强竹纤维复合材料相较于其他传统材料而言具有可降解的优异特性和良好的可回收性,为现代汽车设计提供了良好的参考建议,有利于汽车工业的良性发展,也有助于进一步提升整车的安全性能。