Manufacture and properties of high-performance oriented strand board composite using thin strands

Three-layered composite oriented strand boards were manufactured using very thin hinoki (Japanese cypress, Chamaecyparis obtusa Endl.) strands oriented in the faces and mixtures of sugi (Japanese cedar, Cryptomeria japonica D. Don.) and hinoki particles in the core. The boards were composed of two density levels, with 1:8:1, 0.5: 9 : 0.5, and 0: 10 : 0 face: core: face ratios. Polymeric and emulsion type isocyanate resins were used. The resin contents for the strands in the face and particles in the core were 10% and 5%, respectively. The steam-injection press was applied at 0.62MPa (160°C), and the steam-injection time was 2min. The mechanical and physical properties of the boards were evaluated based on the Japanese Industrial Standard. The parallel moduli of rupture and elasticity along the strand orientation direction and the wood screw retaining force increased with increasing face/core ratios. Incorporation of 10%–20% of thin strands in the face of the boards improved the parallel moduli of rupture and elasticity by 47%–124% and 30%–65%, respectively. In addition, the thickness swelling after water-soaking at 20°C for 24h, and the parallel linear expansion after boiling for 2h and water-soaking at 20°C for 1 h, of the three-layered composite boards were below 8% and 0.15%, respectively, despite a short steam-injection press time. The thickness swelling of the boards decreased with increasing face/core ratios. In contrast, the presence of face strands seems to have a minimal effect on the moduli of rupture and elasticity along the perpendicular direction of the three-layered composite boards. A similar trend was observed for the internal bond strength, hardness, and linear expansion along the perpendicular direction.This paper was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997     

三种竹碎料板的物理力学性能比较分析

对三种竹碎料板的物理力学性能进行了比较分析。板材弹性模量：竹席增强竹碎料板〉竹碎料/木纤维复合板〉普通竹碎料板;静曲强度：竹席增强竹碎料板〉竹碎料/木纤维复合板〉普通竹碎料板;吸水率：普通竹碎料板〉竹碎料/木纤维复合板〉竹席增强竹碎料板;吸水厚度膨胀率：普通竹碎料板〉竹碎料/木纤维复合板〉竹席增强竹碎料板;内结合强度：竹碎料/木纤维复合板〉竹席增强竹碎料板〉普通竹碎料板。     

碳纤维增强聚合物 重组竹复合材的弯曲力学性能

重组竹已广泛应用于室内高档装饰、园林景观、室外防腐地板等领域,但重组竹的弹性模量比较小,为钢材的1/7~1/5,应用于建筑领域时难以充分发挥其自身高强度的特性。针对重组竹刚度较小的问题,提出一种重组竹板和碳纤维增强聚合物(CFRP)厚板嵌合粘接的新型重组竹复合材料,采用三点弯曲试验和有限元仿真方法,对CFRP 重组竹复合试件的失效模式、荷载 位移关系、应变曲线、胶层界面剥离影响等进行了研究。结果表明:重组竹试件失效模式是跨中位置处拉伸区域竹纤维断裂,且出现若干水平分层破坏,CFRP 重组竹复合试件的失效模式是CFRP与重组竹层间胶层出现大面积剥离;CFRP 重组竹复合试件的变形过程分为线弹性阶段和界面破坏阶段;CFRP可以明显提高重组竹梁的弹性模量和静曲强度,复合试件弹性模量是重组竹试件的2.33~2.94倍,静曲强度是重组竹试件的1.49~1.58倍;胶层界面剥离是CFRP 重组竹复合试件失效的重要因素,胶层界面剥离对复合试件的应变分布和挠度都有较大影响,完全剥离后试件的挠度是未剥离时的3.09倍。     

木质人造板的吸声性能试验分析

以胶合板、中密度纤维板和刨花板为试验材料,用驻波管法分别测量3种人造板的吸声系数.结果表明:总体上,人造板材料吸声系数随频率增加而增大;增加材料厚度可以略提高低频的吸声系数;厚度相近的胶合板吸声性能要好于其他2种材料;人造板材料的平均吸声系数不到20%,吸声效果并不理想.     

Analysis of Calcutta bamboo for structural composite materials: physical and mechanical properties

The objective of this study was to determine the technical feasibility of producing a structural composite from Calcutta bamboo. The first article on surface characteristics published in this series addressed pH, buffer capacity, wetting, and surface energy (Ahmad and Kamke 2003). In this paper, the physical and mechanical characteristics were considered for their variability with respect to location along the length of the bamboo culm, nodes versus internodes section, and radial versus tangential directions. The physical and mechanical characteristics were also compared to timber species commonly used in the manufacture of structural composites. The characteristics studied were found to have some variability at different locations, sections, and directions. Calcutta bamboo was found to have similar physical and mechanical characteristics to commercial timber species in Malaysia and North America.     

Effect of board density and layer structure on the mechanical properties of bamboo oriented strandboard

This study examined the effects of density and layer structure on the mechanical properties and dimensional stability of strandboard manufactured from moso bamboo (Phyllostachys pubescens). The strandboard was fabricated in a laboratory at five densities and three different structures including a randomly oriented homogenous board, a unidirectionally oriented homogenous board, and a three-layered board with a cross-oriented core layer (BOSB). Bamboo strand alignment distribution could be predicted using the von Mises distribution function. Bending properties increased with increasing density and were affected by layer structure. The modulus of rupture (MOR) of the threelayered board in the parallel direction increased remarkably compared with the random board MOR; in the perpendicular direction, it exhibited less strength reduction. Elastic properties of the three-layered board could be predicted using elastic constants of the unidirectional board. Internal bond strength (IB) was greatly affected by density, but the layer structure effect did not appear in IB. Linear expansion per unit moisture change ranged from 0.017 to 0.022 for random and three-layered boards; these values are comparable with or lower than values for commercial board.     

Impacts of freezing and thermal treatments on dimensional and mechanical properties of wood flour-HDPE composite

Wood plastic composite (WPC) of wood flour (WF), high density polyethylene (HDPE), maleic anhydride-grafted polyethylene (MAPE) and lubricant was prepared by extrusion, and then exposed to different temperatures to evaluate the effects of freezing and thermal treatment on its dimensional and mechanical properties. At elevated temperatures, WPC expanded rapidly initially, and then contracted slowly until reaching an equilibrium state. Treatment at 52°C and relative humidity of 50% for 16 days improved the mechanical properties of WPC: flexure, tensile strength, and izod unnotched impact strength increased by 8%, 10% and 15%, respectively. Wide-angle X-ray diffraction (XRD) tests showed that the degree of crystalization of HDPE in WPC declined with increasing treatment temperature.     

无机复合型阻燃剂对稻草刨花板阻燃性能的影响

选用氢氧化铝(ATH)与硼酸锌(ZB)组成的无机复合型阻燃剂压制阻燃稻草刨花板,采用锥形量热仪法研究不同配比的ATH和ZB对稻草刨花板阻燃性能的影响。结果表明:无机复合型阻燃剂能有效减少稻草刨花板的热释放和烟释放,减少烟气中CO和CO2的释放浓度,降低燃烧过程中的质量损失速率,表现出良好的阻燃抑烟效果;ATH与ZB具有协同阻燃作用,ZB的加入能有效提高复合阻燃剂的阻燃效果,减少ATH的用量,10%的ATH用量可达到比较好的阻燃效果。     

五种桉树木材的吸声性能

本文以广西东门林场的人工林尾叶桉(Eucalyptusurophylla),尾巨桉(EucalyptusurophyllaE.grandis),尾园桉(E.urophyllaE.tereticornis),尾赤桉(E.urophyllaE.camaldulensis)和大花序桉(E.cloeziana)木材为主要材料,用驻波管法测试了五种桉树木材的吸声系数,比较了这些桉树木材的吸声性能,结果显示五种桉树木材的吸声系数在频率1000赫兹之内变化不大,之后随频率的增加吸声系数也在增加。在频率200至2000赫兹范围内,五种桉树木材的吸声系数差异不显著,在低频区域,尾叶桉的吸声性能较好。在所测试的声波频率范围内,桉木弦锯板的吸声系数高于径锯板;0.5厘米厚的锯材的吸声性能好于1.0厘米厚的锯材;因此,桉木板材的种类和板材的厚度影响其吸声性能,但五种桉树木材的吸声性能差异不显著。图2表4参6。     

仿生木材结构穿孔纤维板吸声性能

以中密度纤维板为基材,通过设计穿孔结构及打孔方式,达到拓宽木质穿孔板吸声频带和提高声学性能的目的.利用分层加工工艺制备了带侧孔结构的穿孔纤维板,采用阻抗管传递函数法对穿孔纤维板吸声性能进行了测试.通过正交试验方法,研究了主孔直径、穿孔率、倾斜角度对穿孔纤维板吸声性能的影响,并获得了较优的制备工艺,随后利用控制变量法研究...     

Sound absorption property of wood for five eucalypt species

The sound absorption coefficients of wood and wood boards for five eucalypt species (Eucalyptus urophylla, Eucalyptus urophylla x E. grandis, Eucalyptus urophylla x E. tereticornis, Eucalyptus urophylla x E. camaldulensis and Eucalyptus cloeziana) that were collected from plantation in Dongmen Forestry Center of Guangxi Province, China were tested with standing wave method and their sound absorption properties were also compared. The results showed that the sound absorption coefficients of the five eucalypt wood species did not change evidently below 1000 Hz, but above 1000 Hz their sound absorption coefficients increased with the increasing frequency. The difference in sound absorption coefficient among five species of eucalypt wood is not evident at the tested frequency range (200–2000 Hz), but the sound absorption property ofEucalyptus urophylla at low frequency is better than that of other four species. The sound absorption coefficient of the tangential-sawn board is higher than that of the radial-sawn board. The sound absorption property of eucalypt wood of 0.5 cm in thickness is much better than that of 1.0 cm in thickness. It is concluded that wood sound absorption properties of eucalypts are affected by their board thickness and the type of sawn timber within the testing frequency, but the variance of wood sound absorption property among the five tested species is not significant. Fundation item This study is Part of 2000-4-13 in “948” Project from the State Forestry Administration of P.R. China Biography: JIANG Ze-hui (1939-), female, Professor in Research Institute of Wood Industry in Chinese Academy of Forestry. Responsible editor: Chai Ruihai     

Development of structural composite products made from bamboo I: fundamental properties of bamboo zephyr board

A study was conducted to determine the suitability of zephyr strand from moso bamboo (Pyllostachys pubescens Mazel) for structural composite board manufacture. Thirty-two 1.8×40×40cm bamboo zephyr boards (BZB) were produced using four diameters of zephyr strand (9.5, 4.7, 2.8, and 1.5mm) and four target densities (0.6, 0.7, 0.8, and 0.9g/cm³). Results indicate that BZB exhibits superior strength properties compared to the commercial products. The size of the zephyr strand and the level of target density had a significant effect on the moduli of elasticity and rupture, internal bond strength, water absorption, and thickness swelling, but they did not have a significant effect on linear expansion. With regard to the physical properties, BZB exhibited less thickness swelling and exhibited good dimensional stability under dry-wet conditioning cycles.Part of this research was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998; it was reported at the 4th Pacific Rim Bio-Based Composite Symposium, Bogor, Indonesia, November 1998     

Influence of pre-treatment in citric acid solution on physical and mechanical properties of thermally compressed oil palm board

Oil palm trunk is an excellent raw material for thermally compressed wood board.However,improvements to dimensional stability during water absorption and reduced thickness swelling has been tied to losses in other mechanical properties,especially as the compression temperature is increased.Toward solving this trade-off,we analyzed the effects of a 48 h pre-soak in citric acid solutions(0,5,15,25,or 35%w/v in distilled water)on the physical and mechanical properties of oil palm board compressed at 140℃.The reference benchmark case was compressed at 200℃without pretreatment.The oil palm board raw materials were obtained from outer,middle and inner parts of trunk.The results showed that the oven-dry density of compressed oil palm board made from different parts of trunk increased with thermal compression(maximum pressure 12.26 MPa for 8 min).The citric acid pretreatment improved water absorption and thickness swelling properties of oil palm board thermally compressed at 140℃,consistent with the citric acid concentration.The carboxyl groups in citric acid cross-link with the hydroxyl groups in the wood.However,no significant difference was found between the benchmark(200℃)and pretreatments with 5 or 15%citric acid.The citric acid altered the wood chemistry during hot compressing at 140℃.Static bending strength,modulus of rupture(MOR),and modulus of elasticity(MOE)slightly decreased with the citric acid pretreatment,matching the effects of high temperature compression at 200℃.     

轻质麦秸板吸声性能的测定

采用驻波管法研究了新型墙体材料－轻质麦秸板的吸声性能。结果表明轻质麦秸板具有良好的吸声性能，其吸声系数为传统建筑材料（混凝土和砖）的10倍左右，优于目前建筑上常用的轻质建筑材料。     

Reducing resin content and board density without adversely affecting the mechanical properties of particleboard through controlling particle size

Density and resin content are two factors that have a signifi- cant effect on the production cost of wood composite. However, particle size affects resin content and density, which suggests that the interaction of these three factors can be manipulated to reduce the board density and resin content of particleboard without adversely influencing its mechani- cal properties. Some mathematical functional forms based on resin con- tent, board density and slenderness ratio were regressed and an appropri- ate form was chosen. According to analysis of the results using SHA- ZAM 9 software, the exponential function best fit the experimental data. Finally, "indifference curves" of mechanical properties were illustrated and analyzed. The results indicated that negative effects of density or resin content reduction on mechanical properties could be compensated for by controlling particles’ slenderness ratio. Interestingly, increases in slenderness ratio compensated for the negative effects of decreases in resin content or board density on module of rupture (MOR) and module of elasticity (MOE). Moreover, this "compensation ratio" intensified as resin content or density decreased and/or as the MOR or MOE increased. On the other hand, reduction in slenderness ratio indicated a comple- mentary effect on reducing internal bond (IB) strength, a result of de- creases in resin content or density. Moreover, this "complementary ratio" was intensified as resin content or density decreased and/or as IB strength increased.     

3种偶联剂对PVC木塑装板力学性能的影响

通过测试PVC基木塑装饰板的物理力学性能,研究3种偶联剂及偶联剂添加量对PVC木塑装饰板的抗弯强度、表面结合强度、板面握螺钉力和吸水厚度膨胀率的影响。结果表明：采用铝酸酯偶联剂PVC木塑装饰板的抗弯强度、表面结合强度、板面握螺钉力最大,72h吸水厚度膨胀率最小为0.47%;同时当铝酸酯添加量2%增加至6%时,PVC木塑装饰板的抗弯强度、表面结合强度、板面握螺钉力分别增加了7.9%、11.9%、10.8%72h吸水厚度膨胀率呈现先减后增趋势。     

竹/玻璃钢复合材料板的研制及性能分析

结合军事野战抗爆结构的战术技术特点,探讨了竹/玻璃铜复合材料的物理性能、动静力学性能及其在抗爆结构设计中的应用,旨在为该材料在其它工程领域的应用提供参考。     

生态木竹纤维复合装饰板材成型工艺

天然纤维复合材料是国内外近年蓬勃兴起的一类新型绿色复合材料。本文研发了一种用于家具及室内装饰的多层复合板,其利用竹、木等植物纤维、原生态树脂、重钙粉为原料,采用共挤复合一次成型工艺实现产品其表层（植物纤维同质透心柔性卷材）与芯层（植物纤维微发泡材料）一次复合成型。同时,结合开炼、捏合和无胶黏剂复合等多项成型工艺新技术。产品生产和使用过程绿色环保,具有广阎的发展前景。     

Manufacture of composite board using wood prunings and waste porcelain stone

The objective of this study was to develop a method for the effective use of both pruned wood and porcelain stone scrap. Thus, we manufactured a wood-porcelain stone composite board, which has excellent waterproof property and incombustibility properties. In addition, we examined the conditions needed to manufacture the wood-porcelain stone composite board as a construction material and evaluated the physical and mechanical properties of this board based on the Japanese Industrial Standard. The main results obtained were as follows: the wood-porcelain stone composite board made from pruned wood and porcelain stone scrap had excellent thickness swelling performance and the board had incombustibility properties that were better than commercial oriented strand board. In both single-layer and three-layer composite boards with weight ratios of porcelain stone particles of 40%, the internal bond strength exceeded the standard value of type 18 particleboard of JIS A 5908. However, the bending properties of the composite board were inferior to the type 18 particleboard standard. Therefore, it will be necessary to improve the bending properties of the board by changing the particle sizes of both the porcelain stone scrap and the pruned wood component. Part of this article was presented at the 57th Annual Meeting of the Japan Wood Research Society at Hiroshima, August 2007