Comparison of internal bond strength and compression shear strength of wood-based materials

The purpose of this study was to design a compression shear device for easy and fast measurement of the bonded shear strength of wood-based materials to replace the conventional method used to evaluate internal bond strength (IB). To assess the performance of this device, five differently sized specimens, included group I (dimension 5 × 1 cm), group II (5 × 2 cm), group III (5 × 3 cm), group IV (5 × 4 cm), and group V (5 × 5 cm) cut from commercial particleboard and medium-density fiberboard (MDF) (1.8 cm thick) were tested in compression shear. Only group V (5 × 5 cm) was prepared for the IB test. Results indicated that the compression shear strengths (CS) of particleboard and MDF, loaded in the horizontal or the diagonal direction, were greater than the IB, although a significant correlation existed between the two. This finding suggests that the IB of particleboard and MDF could be accurately estimated from the data collected by the CS test.Part of this report was presented at the Third Pacific Rim Bio-based Composites Symposium, Kyoto, December 2–5, 1996     

不同温湿度条件对人造板理化性能的影响

以强化木地板、中密度纤维板、高密度纤维板、浸渍胶膜纸饰面人造板等5类人造板为试材,研究标准、模拟夏季、模拟冬季等不同温湿度平衡处理条件对上述人造板内结合强度、吸水厚度膨胀率和表面结合强度值等理化性能检测指标结果的影响。结果表明,高温高湿平衡处理使人造板的力学强度增加,吸水厚度膨胀率降低;低温低湿平衡处理使人造板力学强度降低,吸水厚度膨胀率增加;不同平衡处理条件下强化木地板吸水厚度膨胀率差异较大;对饰面板表面结合强度的影响大于素板。     

浸渍纸层压木地板内结合强度不确定度评定

依照JJF 1059.1-2012《测量不确定度评价与表示》的方法,对浸渍纸层压木地板内结合强度测量试验中影响其测量结果不确定度进行了分析和评定。结果表明：浸渍纸层压木地板内结合强度为：σ=（1.04±0.01）MPa,其中扩展不确定度的包含因子k=2,置信概率p=95%。     

Structural mechanics of wood composite materials I: Ultrasonic evaluation of internal bond strength during an accelerated aging test

This research attempts to observe indirectly the variation of internal bond characteristics for wood composite materials during accelerated aging test treatment using ultrasonic pulse-transmission techniques. Particleboard (PB) and oriented strandboard (OSB) were the representative specimens. The transit time of the ultrasonic wave propagating through the samples along the nominal length and thickness directions was recorded using an apparatus called PUNDIT (C.N.S. Electronic, London). The transit times were measured in the samples under an oven-dried condition after treating them with boiling water at different treating time stages, and the velocity was then calculated based on the transit time. Examination of the internal bond strength conducted on the same samples was done according to JIS A 5908. A study of the relations among springback, internal bond strength, and velocity indicated that a high correlation existed between ultrasonic velocity measured in the length or thickness direction and the internal bond strength for the PB specimen, but no significant correlation was observed between the velocity measured in the length direction and the internal bond strength for the OSB specimen. The results of this research suggested that ultrasound techniques can be applied to predict or evaluate the internal bond state of some wood-composite materials made of relatively small particles, such as PB especially, during accelerated aging test treatment processes.Part of this paper was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997     

工艺参数对稻壳-木刨花复合板内结合强度的影响

采用均匀实验设计方法,通过单因素及两因素间交互作用情况,探讨工艺参数对稻壳-木刨花复合板内结合强度(IB)的影响。在试验研究范围内,密度、芯层比例、芯层施胶量、热压温度、热压时间对复合板IB影响显著,表现为IB随密度的增大先增大后减小,随芯层比例和芯层施胶量的增加而增加,随热压温度和热压时间的增加而减小。当密度为0.77 g/cm3、芯层比例为60%~65%、芯层施胶量为4.5%、热压温度为170℃、热压压力为2.5 MPa、热压时间为20 s/mm时,在兼顾生产效率与生产成本的同时,能够获得IB良好的稻壳-木刨花复合板。     

无纺布衬垫处理对木纤维—合成纤维复合材料性能的影响

用不同的处理剂对无纺布进行预处理，考察其对木纤维-合成纤维复合材料的内结合性能的影响，研究表明，通过对无纺布预处理，可以消除无纺布衬垫对木纤维-合成纤维复合材料的不良影响，处理剂的用量以无纺布重量的100%为佳。     

加热法对石膏刨花板性能影响的研究

研究了加热温度和加压时间对石膏刨花板性能的影响。试验结果表明石膏固化时加适量的热量有助于提高石膏刨花板的性能;加热温度较高时石膏刨花板的性能比常温条件下压制的板的性能低。石膏固化时是吸热反应,石膏刨花板加压固化时,外加一定的热量有助于提高石膏的固化强度,因此板具有较好的物理力学性能。     

Improvement on the properties of gypsum particleboard by adding cement

Gypsum particleboard (GPB) has high thickness swelling (TS), high water absorption (WA), and low mechanical properties compared with cement-bonded particleboard. The properties of GPB were improved by adding cement. The experimental results showed that GPB with the added cement had good physical and mechanical properties compared with those of gypsum particleboard with no added cement. The TS and WA of gypsum particleboard with added cement were reduced by 10%. The mechanical properties of GPB, such as internal bond strength (IB), modulus of rupture (MOR), and modulus of elasticity (MOE), increased when the GPB was made with added cement. The properties of GPB improved relative to the quantity of cement added. With an increase of cement content from 5% to 10%, the TS and WA were reduced, and the IB, MOR, and MOE were increased. In contrast, the TS and WA increased and the IB, MOE, and MOR decreased when the cement content was increased from 15% to 30%. Thus the physical and mechanical properties of GPB were successfully improved when the added cement content was 10%.An outline of this paper was presented at the 47th Annual Meeting of the Japan Wood Research Society in Kochi, April 1997     

酚醛树脂原料配比对麻毡板性能的影响

研究了酚醛树脂的不同原料配比对麻毡板性能的影响。结果表明：1)麻毡板的内结合强度随着F／P摩尔比的增加而增加，随尿素用量的增加而降低；在一定范围内，碱用量、甲基葡萄糖甙(TD)的用量对其影响不大。2)麻毡板的吸水厚度膨胀率随着F／P摩尔比的增加而减少，随着碱、尿素、甲基葡萄糖甙用量的增加而增加。适宜的原料配比为：尿素量在树脂总量的4％，F／P摩尔比为2．0，NaOH／P摩尔比为0．06，甲基葡萄糖甙在树脂总量的4％。     

Determining the effect of tree size,bark-wood bond strength and tree form on the productivity of an excavator-based harvester in Acacia mearnsii in the KwaZulu-Natal forestry region of South Africa

The aim of this study was to determine the effect of tree size, bark-wood bond strength and tree form on the productivity of cut-to-length harvesting of Acacia mearnsii, using an excavator-based harvester with a SP Maskiner harvester head in the KwaZulu-Natal forestry region of South Africa. Tree diameter and height measurements were used to determine individual tree volumes, after which the trees were classified into different bark-wood bond strength and tree-form classes. Time studies were carried out to determine harvester productivity. The results showed that tree size plays a crucial role in the productivity of the harvester, but bark-wood bond strength and tree form also influence productivity. The harvester productivity varied from 5.5 m³ per productive machine hour (PMH) in 0.05 m³ trees to 16.9 m³ PMH^?1 in 0.25 m³ trees The bark-wood bond strength did not influence harvester productivity when handling small trees of less than 0.1 m³. In small trees, the productivity of the harvester was also not affected by different form classes, but as tree size increased, there was greater productivity variation between the different form classes.     

改性骨胶蛋白增量剂对脲醛树脂胶合性能的影响

研究了化学改性骨胶加入脲醛(UF)树脂后对胶合性能的影响。通过对改性胶黏剂的pH、黏度、凝胶时间、耐水性、拉伸剪切强度等性能的讨论,确定了骨胶作为增量剂的加入提高了脲醛树脂本身的应用性能,同时骨胶有一定的甲醛吸附性,为扩大脲醛树脂应用范围提供了参考依据。     

Effect of drying methods on the discoloration of three major domestic softwood species in Korea

1 Introduction Three major softwood species in Korea are Japanese pine (Pinus densiflora), Korean pine (Pinus koraiensis) and larch (Larix leptolepis) which have been used for traditional buildings and furniture for a long period of time. They are easily discolored due to drying and UV irradiation. It has been observed that the discoloration varies with different drying methods and the extent of UV irradiation (Mottonen and Luostarinen, 2001; Kang, 2003). To prevent beech from discolorat…     

聚乙二醇对五硼酸铵改性结构刨花板力学性能的影响

试验引入聚乙二醇改性体系以补偿五硼酸铵对结构刨花板力学性能的影响。结果表明：聚乙二醇可以弥补五硼酸铵对结构刨花板力学性能的降低,内结合强度随五硼酸铵用量的增加有一定程度的增大。五硼酸铵用量、聚乙二醇种类及聚乙二醇用量三个因素对内结合强度有显著影响,对静曲强度和弹性模量均无显著性影响。研究提出改性体系最佳配比为：2．80％的五硼酸铵（基于绝干刨花重）配合20％的PEG-2000（基于酚醛树脂胶粘剂用量）。     

控根对苦楝苗木质量的影响

容器苗根系畸形现象比较严重,采取一定的控根技术可有效改善根系分布,增加侧根数量,提高容器苗质量。试验选用不同控根方法对苦楝苗木进行容器育苗对比试验,阐明了不同控根方法对苦楝苗木质量的影响规律。结果表明,空气修根效果显著,特别是空气控根和化学控根结合的方法处理的苗木其根系成团现象比较明显,侧根数、根系活力等指标与其他处理间均达极显著差异。化学控根采用碳酸铜浓度为100～150 g/L时培育出的苗木质量最好。