提高石膏刨花板耐老化性能的进一步研究

本文研究了矿渣硅酸盐水泥对石膏水化性能的影响;水泥加入量与石膏硬化浆体力学强度的关系;石膏中掺入3～12%的矿渣硅酸盐水泥时,对石膏刨花板静曲强度和耐水性能的影响;石膏刨花板表面涂建筑涂料后,对其耐老化性、耐水性以及静曲强度的影响。     

葡萄藤化学组分及藤/木复合刨花板性能研究

在我国,每年可以产生多达600万t的葡萄藤,它们大多被废弃在田地间,造成了巨大浪费。利用废弃的葡萄藤作为木质刨花板原料的部分替代材料可变废为宝,因此,研究了葡萄藤碎料添加量、施胶量以及等离子体预处理技术对复合刨花板性能的影响。结果表明,由于葡萄藤碎料自身性能较差且无法与木刨花很好地结合,葡萄藤碎料的加入会使得复合刨花板性能下降,在葡萄藤碎料添加量达到25%时葡萄藤/木复合刨花板的静曲强度、弹性模量、内结合强度分别下降了35.9%,35.0%,13.1%,吸水厚度膨胀率增幅为31.2%。施胶量的增大可以改善葡萄藤碎料加入带来的板材性能下降问题。葡萄藤碎料经等离子体预处理改性之后的润湿性能提高,对胶液的吸收能力增强,压制出的葡萄藤/木复合刨花板相比未改性的葡萄藤/木复合刨花板,在施胶量为10%的情况下,其静曲强度、弹性模量、内结合强度分别提升了23.0%,21.6%,10.7%;在施胶量为14%的情况下,分别提升了17.4%,11.8%,7.4%。等离子体处理后葡萄藤碎料与木刨花之间的结合也更加紧密,吸水厚度膨胀率也分别由9.32%和6.85%降至8.68%和5.86%。     

快速固化水泥刨花板的工艺试验

以速生杉木加工剩余物为主要原料、Na2SiO3为快速固化添加剂制备水泥刨花板,研究了冷、热压两种压板方式、Na2SiO3添加量、热压温度、热压时间、水灰比、灰木比、水泥种类和刨花形态等因素对水泥刨花板主要性能的影响.结果表明,热压法可适用于水泥刨花板制造,最佳工艺条件为:Na2SiO3添加量10%、热压温度95℃、热压时间12 min、水灰比0.6、灰木比2.6,制备的水泥刨花板的静曲强度达到10 MPa;采用MgCl2后处理能显著改善板的性能.     

秸秆刨花板性能分析

对普通木质刨花板、麦秸刨花板及稻草刨花板进行了密度、含水率、吸水厚度膨胀率、静曲强度和弹性模量、内结合强度、表面结合强度及握钉力的测试,结果表明,麦秸刨花板在强度方面不及木质刨花板,稻草刨花板在抗弯性能上也无法满足要求,两种秸秆板的握钉力都较差。产生上述差距的关键原因是板坯的密度,另外,与原料形态、加工工艺、机械设备等也有关系。     

枝桠材制备木质刨花板成板工艺及性能研究

采用柳树枝桠材制得的片状刨花制备木质刨花板;通过正交试验设计,研究施胶量、预设密度以及石蜡添加量对板材物理力学性能的影响。结果表明,预设密度对静曲强度和静曲弹性模量均有显著的正相关线性影响,对内结合强度有显著影响;施胶量对静曲弹性模量和内结合强度有一定的正相关影响;所有试验因素对2 h吸水厚度膨胀率均有一定影响。从板材性能和成本角度考虑,确定柳树枝桠材制备木质刨花板的最佳工艺为:施胶量7%,预设密度0.7 g/cm~3,石蜡添加量4%。     

水泥刨花板生产与研究进展

一、引言水泥刨花板是以木质刨花或纤维与水泥为主要原料制成的一种人造板。它兼有木材和水泥的双重性能,与普通的建筑材料相比,具有重量轻、强度大、安裝组合方便以及耐侯、耐潮湿、耐火、耐菌虫、绝缘和机械加工性能好等特点,是良好的工程     

木质与蒿杆混合刨花板的制备

利用蒿秆刨花代替部分木质刨花生产刨花板,试验采用正交试验方法,以刨花板的吸水厚度膨胀率、内结合强度、表面结合强度、静曲强度及握螺钉力等力学性能为评价指标,优化木质刨花与蒿秆刨花混合刨花板的制备工艺。正交试验结果表明,木质刨花与蒿杆刨花原料配比5:5,热压工艺为:热压温度155℃,热压时间40s/mm,施胶量12%。所制备的板材的吸水厚度膨胀率6.31%、静曲强度32.1MPa、握螺钉力1.84kN、内结合强度0.92MPa、表面结合强度0.82MPa。     

不同工艺参数对UF工业大麻秆刨花板性能的影响研究

工业大麻秆是一种优质的轻质非木质原料,利用脲醛树脂为胶黏剂可以制备出性能优良的刨花板产品.笔者主要分析不同的工艺参数,包括密度、热压时间、热压温度和施胶量对板材性能的影响.研究结果表明,密度和施胶量对板材性能的影响要比热压温度和热压时间明显,随着板材密度、热压温度和热压时间的增加,板材的力学性能大多先增加后减小;而随着施胶量的增加,板材的力学性能呈增加趋势.在目标密度0.55 g/cm3,施胶量10％,热压温度130℃或170℃条件下,板材的力学性能可达到国标普通刨花板的标准要求;当目标密度等于或高于0.65 g/cm3、施胶量等于或高于12％、热压温度在140～ 160℃、热压时间在20 ～ 45s/mm之间时,除TS外,板材的其他力学性能可达到国标室内装饰和家具用材的标准要求,并可与相同工艺条件下,目标密度为0.75 g/cm3的木质刨花板的各项性能相媲美.可见,工业大麻秆是一种优质的非木质原料,利用该原料在低温条件下制备低密度的刨花板是可行的.     

水泥刨花板的制造工艺及发展前景

水泥刨花板是以木质刨花为主要原料,辅之以其它化学添加剂经特定工艺生产的一种板材。它是一种性质优良的“代木”产品,是一种理想的新型建筑材料,在我国有很大的发展潜力。本文简要阐述了水泥刨花板的制造工艺和产品性能,并介绍了水泥刨花板在建筑上的应用前景。     

互花米草碎料板的生产工艺

研究以互花米草为原料,以脲醛树脂为胶黏剂制作碎料板的生产工艺。试验表明:在互花米草各部位中以杆部为原料制作出的碎料板性能最好;由于互花米草的表皮存在较高的硅物质,通过加大互花米草茎秆的粉碎程度,使表皮组织尽可能分散,能够显著提高碎料板的性能;互花米草碎料板存在内结合强度和吸水厚度膨胀率性能较差问题,作者尝试通过增加密度和施胶量对性能进行改善,结果表明增加施胶量效果较为明显;将互花米草与木质刨花混合制作木草复合碎料板,容易解决互花米草碎料板内结合强度低的问题,试验中当互花米草的质量分数为35%时,木草复合碎料板的内结合强度超过木质普通刨花板标准要求。     

不同混杂比下竹木复合纤维板的弹性模量

按照不同竹木纤维混杂比试制了竹木复合纤维板,测试了纤维板的弹性模量(MOE),分析了混杂比对MOE的影响。结果表明:竹木复合纤维板的弹性模量符合混杂定律,不同混杂比对竹木复合纤维板呈现不同正负混杂效应,且当竹木纤维混杂比为2:8时,弹性模量最佳,正效应最明显。     

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％。     

分子筛对磷氮阻燃胶合板协效作用的研究

采用单因素法分析了分子筛类型及用量对磷氮阻燃剂浸渍杨木单板制备的胶合板的阻燃性能和胶合性能的影响。研究结果表明:分子筛在磷氮阻燃胶合板中显示出良好的协效阻燃作用。加入量为1%时就能够显著提高阻燃胶合板的阻燃性能,不同类型分子筛对阻燃性能的提高程度依次为4A>5A>13X>3A;分子筛在协效阻燃的同时,还可以提高阻燃胶合板的胶合强度。分子筛加入量为3%时阻燃胶合板的胶合强度提高最大,各类型分子筛对胶合强度的提高程度依次为13X>5A>4A>3A。     

Improvement of dimensional stability and weatherability of composite board made from water-vapor-exploded wood elements by liquefied wood resin impregnation

High-density and high-resin-content boards were produced by phenolic resin impregnation into board materials prepared by the water-vapor-explosion process (WVE) to develop high-durability wood composite boards for exterior use. Wet-dry cyclic tests and accelerated weathering tests were conducted, and the fundamental properties were determined to examine the effect of resin impregnation on board qualities. Bending and internal bond strength of resin-impregnated boards (I-board) satisfied the criterion for 18-type particleboard described in JIS A 5908. Thickness swelling (TS) after 24-h water immersion was approximately 2%. Resin impregnation improved the dimensional stability of the boards. In wet—dry cyclic testing, TS of I-board was the same as that of plywood. The retention ratio of modulus of rupture of I-board was large; thus, I-board had high bond durability. Color change of I-board was less than that of ordinary particleboard after a 500-h accelerated weathering test. I-Board had lower surface roughness than boards produced by a spray application method (S-board) and higher water repellency, although the difference in resin contents of the face layer was small. Thus, it is suggested that the surface properties and weatherability of I-board were improved by impregnation of phenolic resin. High-density and resin-impregnated boards made from the WVE elements are expected to withstand actual exterior use. Part of this report was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

Flexural and visual characteristics of fibre-managed plantation Eucalyptus globulus timber

ABSTRACT

The main goal of this study was to investigate the visual characteristics, recovery rate, and flexural properties of sawn boards from a fibre-managed plantation Eucalyptus globulus resource as a potential raw material for structural building applications. The impacts of the visual characteristics, strength-reducing features, and variation in basic density and moisture content on the bending modulus of elasticity (MOE) and modulus of rupture (MOR) of the boards were investigated. The reliabilities of different non-destructive methods in predicting MOE and MOR of the boards were evaluated, including log acoustic wave velocity measurement and numerical modellings. The MOE and MOR of the boards were significantly affected by the slope of grain, percentage of clear wood, and total number of knots in the loading zone of the boards. The normal variation in basic density significantly influenced the MOE of the boards while its effect on the MOR was insignificant. The numerical models developed using the artificial neural network (ANN) showed better accuracies in predicting the MOE and MOR of the boards than traditional multi-regression modelling and log acoustic wave velocity measurement. The ANN models developed in this study showed more than 78.5% and 79.9% success in predicting the adjusted MOE and MOR of the boards, respectively.     

Bond durability of kenaf core binderless boards I: two-cycle accelerated aging boil test

A two-cycle accelerated aging boil test was conducted on kenaf core binderless boards to estimate their bond durability. This is one of the methods to estimate the bond quality of kenaf core binderless boards, as stipulated by Notification 1539 of the Ministry of Land, Infrastructure, and Transport, October 15, 2001, for the Building Standard Law of Japan. Generally, retention ratios of modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond (IB) strength after the boil test increased with increased pressing temperature. In particular, the MOR retention ratio of boards with a pressing temperature of 200°C (average 106.4%) was higher than that of a commercial medium-density fiberboard (MDF) (melamine-urea-formaldehyde resin) (average 72.7%), and the value sometimes exceeded 100%. The durability of kenaf core binderless boards with a pressing temperature of 200°C compared favorably with that of the commercial MDF (melamine-urea-formaldehyde resin), having almost the same retained strength values after the boil test. Part of this article was presented at the International Symposium on Wood Science and Technology, IAWPS2005, November 27–30, 2005, Yokohama, Japan     

Sound absorption capability and mechanical properties of a composite rice hull and sawdust board

Rice hull–sawdust composite boards were manufactured for sound-absorbing boards in construction. The manufacturing parameters were target density (400, 500, 600, and 700?kg/m³) and rice hull content as percent weight of rice hull/sawdust/phenol resin (10/80/10, 20/70/10, 30/60/10, and 40/50/10). Commercial gypsum board and fiberboard were also used as comparative sound-absorbing materials. The average modulus of rupture (MOR) of the board with a density of 700?kg/m³ and rice hull mixing ratio of 10% was 8.6?MPa, and that of the board with a 400?kg/m³ board density and a rice hull mixing ratio of 40% was 2.2?MPa. The MOR increased with increasing board density or decreasing rice hull mixing ratio. The sound absorption coefficients of some boards (400?kg/m³ and 10%, 500?kg/m³ and 30%, and 500?kg/m³ and 40%) were better than those of the commercial 11-mm-thick gypsum board. Thus, it is concluded that rice hull–sawdust composite boards may be implemented as sound-absorbing barriers in construction due to their high sound absorption coefficients.     

麦秸无胶碎料板制备工艺研究

以麦秸碎料为主要原料,采用漆酶水浴与干法两种不同处理方法压制麦秸无胶碎料板,研究热压温度、热压压力和热压时间对板材物理力学性能的影响。试验结果表明:影响麦秸无胶碎料板物理力学性能的主要因素是热压温度;水浴处理方法压制碎料板的物理力学性能优于干法压制的碎料板;漆酶水浴处理方法较优的热压工艺参数为漆酶用量43.6U/g,含水率10%,热压温度170℃,热压压力3~4MPa,热压时间20~25min。     

Characterization of bagasse binderless particleboard manufactured in high-temperature range

This paper describes the features of binderless particleboard manufactured from sugarcane bagasse, under a high pressing temperature of 200–280 °C. Mechanical properties [i.e., modulus of rupture (MOR) and elasticity (MOE) in dry and wet conditions, internal bonding strength (IB)] and dimensional stability [i.e., thickness swelling (TS)] of the board were evaluated to investigate the effect of high pressing temperature. Recycled chip binderless particleboards were manufactured under the same conditions for comparison, and particleboards bonded with polymeric methylene diphenyl diisocyanate (PMDI) resin were manufactured as reference material. The target density was 0.8 g/cm³ for all of the boards. The results showed that the mechanical properties and dimensional stability of both types of binderless boards were improved by increasing the pressing temperature. Bagasse showed better performance than that of recycled chip as a raw material in all evaluations. Bagasse binderless particleboard manufactured at 260 °C had an MOE value of 3.5 GPa, which was equivalent to the PMDI particleboard, and a lower TS value of 3.7 % than that of PMDI particleboard. The MOR retention ratio under the dry and wet conditions was 87.0 %, while the ratio for the PMDI particleboard was only 54.6 %. The obtained results showed the possibility of manufacturing high-durability binderless particleboard, with good dimensional stability and water resistance, which previously were points of weakness for binderless boards. Manufacturing binderless boards under high temperature was effective even when using particles with poor contact area, and it was possible to express acceptable properties to allow the manufacture of particleboards. Further chemical analysis indicated a contribution of a saccharide in the bagasse to the improvement of the board properties.     

热压工艺对竹重组板材性能的影响

探讨了以竹材为主要原料的竹重组板材热压工艺的优化,研究了热压工艺对竹重组板材力学性能的影响,讨论分析了热压压力、热压时间、热压温度对竹重组板材吸水厚度膨胀率、耐沸水性、静曲强度、弹性模量、耐磨性、耐化学腐蚀性、浸渍剥离率和甲醛释放量等性能的影响。通过正交试验,得出的优化热压工艺为:①热压压力2.0MPa、热压温度145℃、热压时间1.7min/mm,热压压力对竹重组板材耐酸性、静曲强度和弹性模量等影响显著,对耐沸水性、耐碱性、耐盐性、耐磨性和浸渍剥离率等影响不显著。②热压时间对竹重组板材静曲强度有显著影响,对其他试验指标影响不显著。③热压温度对竹重组板材各试验检测指标均有一定的影响,但不显著。