共查询到19条相似文献,搜索用时 171 毫秒
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以大豆蛋白胶为胶黏剂,分别采用剥皮和未剥皮的竹柳枝桠材制备中密度纤维板.探讨了枝桠材树皮与木质部的比例和纤维得浆率,研究了树皮含量、施胶量和板材密度对竹柳纤维板物理力学性能的影响,优化了板材的制备工艺参数,并与脲醛树脂胶制备的剥皮竹柳中密度纤维板进行性能对比分析.结果表明:竹柳枝桠材的树皮含量这30.5%,其纤维得浆率比剥皮枝桠材低约4%;纤维板的性能随着密度和施胶量的增加而明显提高;剥皮竹柳所制纤维板的性能优于未剥皮的,未剥皮竹柳所制纤维板在密度为0.80 g/cm3,施胶量为16%时,其物理力学性能可满足GB/T 11718-2009的要求;而剥皮竹柳所制纤维板在密度为0.75 g/cm3,施胶量为14%时即可达到国标要求;大豆蛋白胶所制纤维极性能略低于脲醛树脂所制纤维板,但基本可以满足国标要求. 相似文献
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《林产工业》2015,(11)
以竹柳枝丫材和3年生小径材为原料,采用脲醛树脂胶分别制备中密度纤维板。对比分析枝丫材与3年生小径材的密度、化学成分、纤维得浆率和纤维形态,研究施胶量和板材密度对竹柳纤维板物理力学性能的影响。结果表明:竹柳枝丫材的密度小于小径材的密度;竹柳枝丫材与小径材均有较高的综纤维素含量;竹柳枝丫材的纤维得浆率低于竹柳小径材;竹柳枝丫材、小径材纤维的壁腔比均小于1,是良好的纤维原料;竹柳枝丫材与小径材所制板材的性能均随着密度和施胶量的增加而明显提高;竹柳枝丫材所制纤维板的性能略低于小径材的,竹柳枝丫材所制纤维板在密度为0.75g/cm~3,施胶量为14%时,其物理力学性能可满足GB/T 11718—2009的要求;而竹柳小径材所制纤维板在密度为0.70g/cm~3,施胶量为14%时即可达到国标要求。 相似文献
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《中南林业科技大学学报(自然科学版)》2016,(1)
以耐盐竹柳为原料,对其进行纤维形态分析,并分别将剥皮竹柳纤维和不剥皮竹柳纤维试制中密度纤维板,探讨胶粘剂施加量和板材密度对纤维板弹性模量(MOE)、静曲强度(MOR)、内结合强度(IB)和吸水厚度膨胀率(TS)的影响。结果表明:密度和施胶量均对其性能指标具有显著的影响,板材性能随着密度和施胶量的增加而提高;剥皮的竹柳纤维制得的纤维板性能优于未剥皮纤维制得的板材;剥皮竹柳纤维制造的纤维板在板密度为0.75 g/cm3、施胶量为12%时,其物理力学性能指标MOE、MOR、IB、TS都达到了国家标准GB/T11718-2009的要求;而未剥皮纤维制得的纤维板在施胶量为14%、板密度为0.75 g/cm3时,其性能指标达到国家相关标准的要求;树皮对纤维板的物理力学性能有明显的影响。 相似文献
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超轻质中密度纤维板生产的可行性 总被引:3,自引:1,他引:2
针对中密度纤维板存在密度偏高的问题,通过提高施胶量,降低了制品密度。研究探讨了利用杉木间伐小径材为
木材原料生产超轻质中密度纤维板的可行性。 相似文献
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通过对火炬松制造中纤维板制板工艺条件的研究,探索降低中密度纤维板制造过程中纤维施胶量的可能性。结果表明,火炬松制造中密度纤维板是可行的;采用8%的施胶量制板;板材的主要物理力学性能可达到美国MDF国家标准ANSTA208.2-1994和我国MDF国家标准70型及80型特级品的要求。 相似文献
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麻竹制备竹基纤维复合材料的性能初探 总被引:1,自引:0,他引:1
为了探索利用麻竹制备竹基纤维复合材料的性能,首先利用纤维可控分离技术将麻竹制备成纤维化竹单板,经过浸胶干燥后,采用热压法制备竹基纤维复合材料,并探讨密度对其耐水性能和力学性能的影响。结果表明,采用热压法制备的竹基纤维复合材料的性能较优,已超过重组竹地板标准规定的室外用地板的指标值。随着密度的增加(0.90~1.15g/cm~3),麻竹竹基纤维复合材料的耐水性能得到改善,其静曲强度、弹性模量和水平剪切强度等主要力学性能增强。在应用中可以考虑在保证板材使用性能的前提下,尽量降低竹基纤维复合材料的密度以节约成本。 相似文献
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Cheng Xing S. Y. Zhang James Deng Bernard Riedl Alain Cloutier 《Wood Science and Technology》2006,40(8):637-646
The properties of medium-density fiberboard (MDF) panels as affected by wood fiber characteristics were investigated. Wood chips from three softwood and one hardwood species were refined under the same refining conditions to make four different types of fibers. The resulting fibers were characterized by fiber size distribution, bulk density, pH value, and buffering capacity. Using the same resin system and hot-pressing parameters, MDF panels were produced and evaluated for internal bonding (IB), modulus of rupture (MOR), modulus of elasticity (MOE), thickness swelling, and linear expansion. The pH values and alkaline buffering capacities of raw materials were reduced considerably after refining. IB was strongly related to the pH value of fibers. The mechanical properties increased with alkaline buffering capacity. IB, MOR, and MOE increased with the bulk density of fibers. Increased proportions of coarse fibers had negative effects on the panel mechanical properties. 相似文献
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Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to study ambient-aged wood
fibers and their effects on the mechanical properties of medium-density fiberboard (MDF). It was found that MDF made with
ambient-aged fibers had poorer mechanical properties than MDF made with fresh fibers; this difference resulted from the alterations
of surface characteristics of wood fibers after ambient aging, which led to poor wettability of the urea–formaldehyde (UF)
resin applied to the aged wood fibers. After 6 months of ambient aging, the concentration of carbonyl groups in the fibers
increased by 144%, while the pH value of wood fiber decreased from 5.2 to 4.7. SEM showed that much more UF resin agglomerated
on the surface of ambient-aged fibers and the breakage of MDF made with aged fiber frequently occurred at the resin-fiber
interfaces, indicated the poorer wettability of UF resin to fibers due to the decrease in surface energy after aging. 相似文献
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Thomas Walther S. Nami Kartal Won Joung Hwang Kenji Umemura Shuichi Kawai 《Journal of Wood Science》2007,53(6):481-486
The development of oriented fiberboards made from kenaf (Hibiscus cannabinus L.) and their suitability as a construction material has been investigated. Three different types of boards consisting of
five layers with individual orientations were prepared using a combination of low molecular weight and high molecular weight
phenol-formaldehyde (PF) resin for impregnation and adhesion purposes. Additional boards with the same structure were prepared
using high molecular weight PF resin only. The mechanical properties of the boards have been examined as well as their resistance
against fungal decay and termite attack. All kenaf fiberboards showed elevated mechanical properties compared with medium-density
fiberboard made from wood fibers, and showed increased decay and termite resistance. Differences in the decay and termite
resistance between the board types were caused by the presence of the low molecular weight PF resin for the impregnation of
the fibers. No significant difference was found for the mechanical properties. The effect of the PF resin for impregnation
was much clearer in fungal decay resistance than for termite resistance; however, fiber orientation had no effect on both
decay and termite resistance of the specimens. 相似文献
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稻草中密度纤维板用改性脲醛树脂的研究 总被引:2,自引:2,他引:2
对比三聚氰胺、二甲基硅油、硅树脂和偶联剂KH-550四种改性剂改性的脲醛(UF)树脂性能的差别及其对稻草中密度纤维板性能的影响,并进行经济评价,最终确定适用于稻草纤维板的改性UF树脂的工艺条件,同时借助于红外光谱(FT-IR)和差热扫描分析(DSC)研究最佳改性UF树脂的结构和固化特性.结果表明,三聚氰胺改性脲醛(MUF)树脂不论是对树脂性能、板性能改善还是从成本分析方面均为稻草纤维板最佳的胶黏剂,FT-IR显示出与未加三聚氰胺相比,加入三聚氰胺后树脂的羟甲基含量降低了10 %,DSC分析则表明其峰值温度有较大幅度的提高,但放出的热量较少.加入三聚氰胺改性的UF树脂其表面张力变小. 相似文献
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Oliver Mertens Kim C. Krause Matthias Weber Andreas Krause 《Wood material science & engineering》2020,15(2):114-122
ABSTRACTThermomechanical wood fibers, as usually used for medium density fiberboard or cardboard production, feature promising characteristics, like a high aspect ratio, for the utilization in thermoplastic composites. The present study investigates the influence of fiber loading and fiber geometry on the mechanical properties of wood-polypropylene composites in order to confirm the results that were found in a previously published literature review. Composites were compounded at fiber contents from 20 to 60 wt.%, using a co-rotating twin-screw extruder and subsequently injection molded to test specimens. Field emission scanning electron microscopy was carried out to evaluate the fracture morphology of the composites. Fiber length was evaluated using an applying a dynamic image analysis system. Compounding reduced fiber lengths up to 97%. The mechanical properties decreased with increasing fiber content for composites without a coupling agent. Strength properties peaking at a fiber content of 50?wt.% for composites containing MAPP. Tensile strength and flexural strength reached 48.1 and 76.4 MPa, respectively. However, it was found that the processing of these fibers into conventional compounding equipment is still challenging. 相似文献
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Abdel-Baset A. Adam Houssni El-Saied Mahmoud K. Soliman 《Wood material science & engineering》2014,9(1):49-57
Sesbania fiber is a fast-growing wood species that has been investigated for medium-density fiberboard (MDF) production. To assess the possibility of applying the local industrial defibration parameters of sugar-cane bagasse (SCB) on defibration of sesbania, the chemical constituents of unfibrated and defibrated sesbania, as well as their thermal stability and scanning electron micrographs, were estimated. Different preparation variables of MDF, such as density, level of urea-formaldehyde (UF) resin (with 0.19% free-formaldehyde [HCHO]), and pressing time were studied, in comparison with that produced by using SCB fibers. The results showed that most of the tested sesbania-based MDFs have mechanical properties that fulfill the minimum requirements of MDF ANSI standard. Additionally, applying 12% UF and pressing for 240 sec provided sesbania-based MDF with optimum reduction in thickness swelling (reached ~7%). It is important to note that the sesbania-based MDF produced under these conditions is characterized by a lower TS property, than that obtained from SCB, or that reported in standards. The preliminary feasibility study revealed that using sesbania fibers will be an added economical potential for MDF production. 相似文献
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Yoichi Kojima Ayaka Kawabata Hikaru Kobori Shigehiko Suzuki Hirokazu Ito Rie Makise Masaki Okamoto 《Journal of Wood Science》2016,62(6):518-525
Wood-based materials are fabricated with adhesives composed of various materials derived from fossil fuels. It is difficult to identify replacements for these chemical adhesives. This study explored nanofiber technologies as an alternative to these adhesives. In this study, we focused on reinforcement effects of lingo-cellulose nanofiber (LCNF) on fiberboards made from softwood and hardwood fiber. We discuss the density effects of reinforcement with LCNF because the density of medium-density fiberboard (MDF), which is widely used for construction, is standardized at about 0.60–0.80 g/cm3. Fiberboards were manufactured with three densities (0.60, 0.75, and 1.00 g/cm3). For softwood fiberboards, the bending properties for LCNF-mixed boards were higher than those for the control fiberboards at all densities. In this paper, control fiberboard means fiberboard with fiber only. For hardwood fiberboards, the bending properties for LCNF-mixed fiberboard for 1.00 g/cm3-density board were higher than those for the control fiberboard. For internal bond strength (IB), the IB for LCNF-mixed fiberboard was higher than that for the control fiberboard. The thickness swelling (TS) and weight change (WC) with water absorption for fiberboards containing LCNF were lower than those for control fiberboards. As a conclusion, physical and mechanical properties of the resulting fiberboards were significantly improved with the addition of LCNF, especially for softwood fiberboards, due to close binding between LCNF and wood fibers. 相似文献
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A global model for the hot-pressing of MDF 总被引:2,自引:0,他引:2
The hot-pressing operation is the final stage in medium-density fiberboard (MDF) manufacture, where the mattress of fibers is compressed and heated to promote the cure of the resin. In MDF hot-pressing, many physical, chemical and mechanical processes are involved; the complexity of this operation arises from the fact that they are coupled. A global model is presented for this operation that integrates all mechanisms involved in the panel formation (heat and mass transfer, chemical reaction and mechanical behavior). This approach results in a two-dimensional unsteady state problem, which involves the knowledge of the polymerization kinetics of the resin, the transport properties and material properties, which are position and time dependent. This dynamic model was used to predict the evolution of the variables relating to heat and mass transfer (temperature, moisture content, gas pressure and relative humidity), as well as the variables relating to mechanical behavior (pressing pressure, strain, modulus of elasticity and density). The model performance was analyzed using the typical operating conditions for the hot-pressing of MDF and the results were compared to the experimental data from an industrial MDF press. We concluded that the model could predict in an acceptable way the behavior of the key variables for the control of the pressing cycle, as well as some physico–mechanical properties of the final product. The improvement of this model will permit the scheduling of the press cycle to fulfill objectives of minimization of energy consumption, better quality of the board and increased process flexibility. 相似文献