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酚醛树脂浸渍处理对杉木单板层积材性能的影响 总被引：2，自引：0，他引：2
采用自制低分子量酚醛树脂浸渍处理杉木单板,探讨了浸渍处理工艺对其增重率和单板层积材性能的影响,研究结果表明在常温常压和加压条件下,增重率均随浸渍时间的延长而增加,随着增重率的增大,板材密度逐渐增大,吸水厚度膨胀率(TS)逐渐降低,静曲强度(MOR)和弹性模量(MOE)先增大后减小.干增重率52.5％时,MOR和MOE达到最大,分别为51.19MPa和10 886MPa,MOR达到了GB/T 20241-2006《单板层积材》120E优级,MOE达到了100E级.鉴于产品质量和生产成本,建议采用浸胶法生产杉木单板层积材时,干增重率控制在50％左右,湿增重率控制在160％左右. 相似文献
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以杨木单板和竹帘为原料,采用低分子量水溶性酚醛树脂浸渍处理,通过干燥、组坯、热压等工艺制备竹木复合强化单板层积材。探讨了组坯方式、压缩率、热压温度、热压时间4个因素对竹木复合强化单板层积材弹性模量(MOE)和静曲强度(MOR)的影响。结果表明:表层为一层竹帘的竹木复合强化单板层积材的MOE和MOR较大,分别是13．43GPa、148．13MPa,与表层为杨木单板次表层为竹帘组坯方式相比分别增加了33．63％、56．16％。确定了竹木复合强化单板层积材较合理的制造工艺参数。 相似文献
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以自制低分子量酚醛树脂为胶黏剂,采用热压工艺对杉木单板进行密实化试验,研究干燥温度、压缩率、热压温度和热压时间对密实型杉木单板层积材力学性能的影响.结果表明:压缩率对层积材力学性能影响最大,其次是干燥温度、热压温度和热压时间;随着压缩率和热压温度的提高,板材的MOE、MOR都有不同程度的提高;随着干燥温度的提升和热压时间的延长,板材的MOE、MOR都呈先增大后减小的趋势;综合考虑,确定密实型杉木单板层积材的最佳热压工艺为:干燥温度60℃、压缩率35％、热压温度145℃、热压时间1.0 min/mm,在此热压工艺条件下制得的板材,其MOE和MOR分别达到了GB/T 20241-2006《单板层积材》120E级和180E优级. 相似文献
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采用低分子量酚醛树脂制备杨木单板层积材,对该产品的静曲强度影响因子进行分析。结果表明:PF树脂的浓度和单板的压缩率对低分子量PF型杨木单板层积材的静曲强度影响显著;酚醛树脂浸渍杨木单板后提升了单板本身的MOR,这对增强杨木单板层积材的MOR起到了促进作用;MOR平均值随着压缩率的增加而提高,25%和35%两个压缩率水平对MOR平均值的影响差别很大,而15%和25%两个压缩率水平对MOR平均值的影响差别较小。 相似文献
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采用低分子量酚醛树脂浸渍处理小径级马尾松单板,探讨常温常压下不同浸渍时间及不同压缩率对马尾松单板层积材物理力学性能的影响。结果表明：常温常压下,马尾松单板随着浸渍时间(8 h、14 h、26 h)的延长,其干湿增重率都呈增长趋势;压缩率(10%、20%、25%)的增加均能提高LVL的密度、尺寸稳定性、MOE和MOR。参考GB/T 20241-2006《单板层积材》,3种不同浸渍时间和不同压缩率下生产的LVL,MOR都达到了180E优级,MOE最低达到120E级,最高可达180E级。 相似文献
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The purpose of this study was to develop a cost-effective method to manufacture high-performance laminated veneer lumber (LVL) from mountain pine beetle (MPB)-affected veneers through partial resin impregnation and optimum board layup. Dry MPB-affected veneer sheets were segregated into two stress grades based on dynamic modulus of elasticity (MOE). A new phenol formaldehyde resin with a 30% solids content was formulated for resin impregnation. To reduce resin consumption, only veneer sheets used as outer layers were dipped in the resin for 5?min and then dried to manufacture 13-ply LVL. The bending properties, shear strength and dimensional stability of these LVL billets were examined and compared to those from the controls made from entirely untreated veneers. The results demonstrated that high-grade (E1) MPB-affected veneers had lower resin solids uptake than low-grade (E2) counterparts based on a 5?min dipping. Compared with the controls, the LVL billets made from resin-impregnated veneers for outer layers yielded increased surface hardness, significantly improved dimensional stability, shear strength and modulus of rupture on both edgewise and flatwise as well as better appearance with no cosmetic concerns. However, the improvement in LVL bending MOE was dependent on initial veneer stress grade. For high-grade (or density) E1 veneers, the use of impregnated veneers resulted in insignificant improvement in bending MOE. The optimum product layup was to place one ply of impregnated E1 grade veneer each for product face and back. By contrast, for low-grade (or density) E2 veneers, the use of impregnated veneers yielded a significantly higher flatwise bending MOE compared to the controls. The recommended product layup was the placement of two plies of impregnated E2 grade veneer sheets each for product face and back. 相似文献
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Ajaye Babatunde 《林业研究》2011,21(1):111-115
Cement-bonded particleboards of 6 mm in thickness were manufactured using maize stalk (Zea mays) particles of uniform sizes at three levels of board density and additive concentrations respectively. The bending strength and dimensional properties were assessed. Increase in board density and additive concentration caused increase in Modulus of rupture (MOR), Modulus of elasticity (MOE), and decrease in Thickness swelling (TS) and Water absorption (WA). The MOR, MOE and TS of the boards were significantly affected by board density except for WA, but additive concentration affected all the boards’ properties examined at p ≥ 0.05. Strong and dimensional stable cement-bonded boards could be manufactured from maize stalk particles with Portland cement as the binder after hot water treatment. Although the dimensional stability and mechanical strength properties of the boards were affected by the board density and additive concentration, the study revealed that cement-bonded particleboards could be manufactured from maize stalk (Zea mays) particles. However, the increase in board density and additive concentration could cause the increase in MOR and MOE, and cause the decrease in TS and WA of boards. 相似文献
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杨木单板的湿热处理规律以及对杨木单板层积材性能影响的研究结果表明,单板湿热处理后产生了塑化,形成了一部分不可恢复的变形,密度平均增加了38.7%;对抗拉强度的影响不显著;对单板压缩率和膨胀率有着特别显著的影响,单板平均压缩了27.8%,经24h水浸泡,单板恢复膨胀仅18.7%.单板湿热处理后经过低压压制,可以得到与高压压制相同密度的板材,且板材的断面密度差异小,水平剪切强度提高了27.1%,静曲强度增加了17.8%,弹性模量没有显著变化,吸水厚度膨胀率降低了约10个百分点. 相似文献
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杉木积成材竹片贴面工艺探讨 总被引：1，自引：0，他引：1
杜春贵 《林业机械与木工设备》2003,31(12):35-36,39
对杉木积成材进行了竹片贴面的初步试验，结果表明：杉木积成材进行竹片贴面切实可行；竹片贴面后的杉木积成材密腹略高于基材；竹片与基材之间的胶合强度大于基材内部的胶合强度；贴面板的MOR和MOE高于基材：24h吸水厚度膨胀率佟明显低于基材。 相似文献
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《Wood material science & engineering》2013,8(1):25-29
Abstract The objective of this work was to evaluate the performance of particleboard manufactured from roselle (Hibiscus sabdariffa) stalks and eucalyptus (Eucalyptus camaldulensis) wood. The manufacturing parameters were various roselle (Hibiscus sabdariffa) ratios in the mixture (0, 25, 50, 75 and 100%) and press time (3, 5 and 7 min). Modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding (IB) strength values and thickness swelling (TS) after 24-hour water soaking of the panels were determined according to the procedure of European Union (EN) Standard. The results of the study demonstrate that roselle stalks can be an alternative raw material source for particleboard industry. With an increase of roselle particles from 0% to 100%, the TS was reduced, and the IB, MOR and MOE were increased. The highest MOE, MOR, IB strength and TS values of the samples were found as 2754.18, 16.81, 0.89 N/mm2 and 15.26% for the panels made using 100% roselle with a 7-min press time, respectively. 相似文献
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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 相似文献