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Bhavadee Iamtasna Taviwan Piyasombatkul Seeroong Prichanont Chirakarn Muangnapoh 《Journal of Wood Science》2010,56(3):184-188
Teak veneer was treated with a commercial hemicellulase from Thermomyces lanuginosus in sequence with hydrogen peroxide or a hydrogen peroxide-laccase mixture to improve the veneer surface color and at the
same time to reduce the necessary amount of hydrogen peroxide. The removal of a small portion of hemicellulose from the teak
veneer surface could be carried out after treatment with the hemicellulase preparation as 0.05 xylanase unit/ml for 30 min.
The veneer samples immediately after the hemicellulase treatment were subjected to the designated concentration of hydrogen
peroxide or hydrogen peroxide-laccase mixture at 60°C at pH 6.5 for 4 h. The changes in veneer color were measured by using
imaging technology as percentage change in gray scale. A treatment combination of hemicellulase containing xylanase, hydrogen
peroxide, and laccase yielded a color improvement close to that achieved using 20% hydrogen peroxide. The results showed that
hemicellulase pretreatment could improve the bleachability of teak veneer surfaces treated with hydrogen peroxide or hydrogen
peroxide-laccase mixture. 相似文献
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为考察硅铝无机防腐处理对竹材表面颜色的影响,以毛竹为材料,采用不同热处理溶液浓度(0、25%、50%、100%)、处理温度(140、160、180℃)和处理时间(1、2h)分别对其进行处理。依照标准色度系统指定表征防腐处理前后竹材表面颜色,通过颜色总色差、明度、红绿色指数、蓝黄色指数的变化,探讨防腐处理工艺参数对竹材表面颜色的影响。通过傅里叶红外光谱和X衍射光谱分析防腐液与竹材结合方式,并使用场发射扫描电子显微镜观察对比处理前后防腐液在竹细胞腔内的分布情况。结果表明,防腐液浓度对竹材色差变化影响较大,随着浓度的增大,竹材色差也随之增大。热处理工艺的处理温度与处理时间对竹材表面颜色的影响也符合传统木材热处理色差变化规律。微观检测发现,防腐剂不仅与纤维有化学键结合,也通过物理吸附以分子团聚形式附着填充在细胞腔内部。 相似文献
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This study evaluated the protection effectiveness of alcohol-borne reagents for the green color of ma bamboo (Dendrocalamus latiflorus Munro) and moso bamboo (Phyllostachys pubescens Mazel). The results show that the types and concentrations of alcohol-borne reagents, the kinds of solvent, and the conditions
of treatment greatly affected the green color of these two bamboo species. Without alkali pretreatment, an excellent green
color protection (a* = −14.5) was obtained when the ma bamboo culms were treated with 0.5% methanol-borne copper chloride (CuCl2) at 60°C for 30 min. Similar results were also obtained when ma bamboo culms were treated with 0.5% methanol-borne copper
nitrate [Cu(NO3)2] at 60°C for 2 h (a* = −13.5). For moso bamboo, an attractive green color in the bamboo culms was achieved by treating the specimens with 1%
methanol-borne copper acetate [Cu(CH3COO)2] at 60°C for 30 min. The a* value of treated specimens was −13.3. In addition, results demonstrated that ultrasonic treatment was more effective on
green color protection than conventional water bath treatment. When moso bamboo was treated with 1% copper acetate at 60°C
in an ultrasonic bath for only 15 min, a remarkable green color with an a* value of −13.6 was obtained on the bamboo epidermis. 相似文献
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Mustafa Kemal Yalinkiliç Rifat Ilhan Yuji Imamura Munezoh Takahashi Zafer Demirci Ahmet Cihangir Yalmkiliç Huseyin Peker 《Journal of Wood Science》1999,45(6):502-514
Outdoor performances of a polyurethane varnish and an alkyd-based synthetic varnish coated over chromium-copper-boron (CCB)-impregnated Scots pine (Pinus sylvestris L.) and chestnut (Castanea sativa Mill.) [10 (R) × 100 (T) × 150 (L) mm] were investigated. These varnishes were also applied to the wood surface as sole coatings or impregnated into wood as water-repellent (WR) solutions. Outdoor exposure was performed in the Black Sea region of northern Turkey (41°N, 39.43°E) where humid weather predominates throughout the year and accelerates decomposition of coated wood surfaces. The wood panels were exposed at 45° south on their tangential surfaces. After 9 months of exposure to summer, autumn, and the following winter season, the color and glossiness changes of the exposed surface, adhesion of the coating layer to the wood surface, water absorption through the coating layers, mass loss, and the hardness of the board surface were studied. CCB impregnation greatly stabilized the surface color of varnish-coated panels of both wood species. Gradual decreases of adhesion between varnished layers and preimpregnated surfaces were attributed to probable weakening of interactions at the interface of the treated wood and the film layer. A superficial cleaning process of treated wood is suggested to improve glossiness and adhesion. The coated wood surface became harder with time on outdoor exposure until a maximum hardness occurred followed by softening, whereas the uncoated surface softened steadily. Polyurethane varnish yielded a harder surface than synthetic varnish. Mass losses of wood panels after 9 months of exposure were negligible for all treatments compared with the untreated controls, which were totally discolored and eroded on the surface. It is concluded that long-term exterior wood protection has been achieved by a successful combination of an appropriate preservative treatment followed by a compatible surface-coating process. 相似文献
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The objective of this study was to find an effective method for treating ma bamboo (Dendrocalamus latiflorus) and moso bamboo (Phyllostachys pubescens) using new water-based reagents containing copper. The effects of green-color protection using various treatments on bamboo
culms were examined in this study. Two methods were used: heating in a water bath and ultrasonic dipping. The results revealed
that excellent green-color protection (a* value of −6.2) was obtained when ma bamboo culms were treated with 0.25% ammoniacal copper quaternary compound-type B (ACQ-B)
in a water bath at 100°C for 2 h. It was also found that the wettability of bamboo epidermis increasedsignificantly after
pretreatment in a mixture of 1% KOH and surfactant in a water bath at 100°C for 30 min. Furthermore, pretreated moso bamboo
culms exhibited excellent green-color protection after they were treated with 0.25% ACQ-B at 100°C for 2 h (a* value of −8.2). This novel treatment method definitely endows the bamboo culms with a fascinating green skin color and consequently
could increase the economic value of bamboo products. No improvement in green-color protection was found when ultrasonic energy
was added to the water bath at ambient temperature. 相似文献
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The attractive green color of moso bamboo (Phyllostachys pubescens Mazel) culms fades without chemical treatment. Chromated copper arsenate (CCA) has been used to protect the green color of bamboo, but CCA is harmful to factory workers and the environment. To overcome the toxicity of arsenic in CCA, two chromium-based formulas developed by the authors, chromated copper phosphate (CCP) and chromated phosphate (CP), were evaluated for their protection of the green color of moso bamboo. The results revealed that bamboo treated with CP had a greener color than those treated with CCA or CCP. The concentration, treatment time, and CrO3/H3PO4 ratio in CP solution greatly affected the color of moso bamboo culms. The attractive green color, which resembles the color of fresh-cut moso bamboo, was obtained by treating bamboo with 2% CP solution at 60°C for 3h, using a 11 CrO3/H3PO4 ratio in aqueous solution. In addition, the CP-treated moso bamboo exhibited excellent green color fastness in both accelerated ultraviolet lightfastness testing and outdoor weathering exposure. 相似文献
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Wendi Liu Tingting Chen Xiaoyun Wen Renhui Qiu Xincong Zhang 《Wood Science and Technology》2014,48(6):1241-1255
Bamboo fibers were mechanically extracted from raw green bamboos by crushing, rolling, and combing techniques with 1,4-butanediol as a solvent. The morphology of the bamboo fibers thus obtained was analyzed. The bamboo fibers were treated with isocyanatoethyl methacrylate (IEM) in the presence of dibutyltin dilaurate as a catalyst, to improve the interfacial adhesion between the fibers and unsaturated polyester (UPE) resins. The bamboo fibers reinforced UPE composites were prepared by hand lay-up compression molding. FTIR, XPS, and NMR analyses indicated that the IEM was covalently bonded onto the bamboo fibers via carbamate linkages. The IEM treatments significantly increased the tensile strength, flexural strength, flexural modulus, and water resistance of the resulting composites and yet decreased the impact strength of the composites. The SEM images of the tensile-fractured surfaces of the IEM-treated bamboo fibers–UPE composites revealed that the fiber treatments markedly improved the interfacial adhesion between the bamboo fibers and UPE resins. 相似文献
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Yan Yu Zehui Jiang Ge Wang Genlin Tian Hankun Wang Ye Song 《Wood Science and Technology》2012,46(4):781-790
Imparting excellent preservative performances to bamboo is the key to expand the applications of this extraordinary non-wood forest resource. This study reports on the formation of ZnO-nanostructured network films on the surface of bamboo via a simple two-step process. This process consists of the generation of ZnO seeds on the bamboo surface followed by a solution treatment to promote the crystal growth. The morphology and chemical composition of the ZnO films were studied by field-emission scanning electron microscopy combined with energy-dispersive X-ray analysis and X-ray diffraction. Accelerated weathering was used to evaluate the photostability of the treated wood. The antifungal and antibacterial performances were also examined. The results indicate that the approach can simultaneously furnish bamboo with excellent photostability and antifungal and antibacterial performances. The growth mechanism of ZnO-nanostructured network films on the uneven and chemically complicated surface of bamboo was also discussed. 相似文献
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Ma bamboo (Dendrocalamus latiflorus Munro) treated with chromated phosphate (CP) exhibits an excellent green color. To understand the effects of the treatment sequence of CrO3 and H3PO4 and their interactions regarding green color protection, CrO3-H3PO4 and H3PO4-CrO3 two-step treatments plus a H3PO4-CrO3-H3PO4 three-step treatment were carried out in this study. Results revealed that the treatment sequence of CrO3 and H3PO4 definitely affects the effectiveness of bamboo color protection. Green color protection of ma bamboo culm could not be achieved by treating it with CrO3 or H3PO4 alone or with the H3PO4-CrO3 two-step treatment. Only by treating it with the CrO3-H3PO4 two-step treatment or the H3PO4-CrO3-H3PO4 three-step treatment did ma bamboo exhibit an excellent green color. The results indicated that bamboo reacts first with CrO3 and then forms an insoluble complex with H3PO4, which produces the green color on its epidermis. Chlorophyll analyses demonstrated that chlorophyll is not a key factor for green color protection. The green pigment was also formed when chlorophyll-free bamboo was treated with 2% CP at 60°C for 3h. 相似文献
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采用滑动弧冷等离子体对竹条和圆竹筒进行处理,并将处理后的样品进行复合型防护药剂加压浸渍处理。采用质量增加率、平衡含水率、湿胀率以及竹条和竹筒的抗压强度等指标来考察防护药剂处理后对竹材性能的影响,并观察竹条和圆竹筒防护处理后的发霉情况。实验结果表明,竹条和圆竹筒表面在加压条件下对二羟甲基二羟乙基乙烯脲(2D树脂)+戊唑醇与丙环唑(PT)+碘代丙炔基氨基甲酸丁酯(IPBC)复合型树脂防护剂的渗透性和附着性得以提升,表现为竹条和圆竹筒经滑动弧冷等离子体和防护药剂加压浸渍处理后质量增加率提高,而平衡含水率和湿胀率下降。对竹条和圆竹筒的质量增加率、平衡含水率、湿胀率和抗压强度产生积极影响的顺序为:冷等离子体处理+加压浸渍防护药剂>加压浸渍防护药剂>未经任何处理的竹条和圆竹筒。此外,竹节的多少也对竹材的质量增加率、平衡含水率和湿胀率产生影响,影响顺序为:无节>单节>双节。处理后,竹条和圆竹筒具有优异的防霉特性,存放半年后,圆竹筒仍能保持原来的物理特征,竹条和圆竹筒表面和端部均无发霉、腐朽和开裂现象。 相似文献
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Anatta Patcharawijit Ram Yamsaengsung Nuttaporn Choodum 《Wood material science & engineering》2020,15(5):261-268
ABSTRACT This research was aimed to investigate mechanical properties, color and cell-wall components changes, and durability of pre-dried rubberwood (Hevea brasiliensis) after superheated steam (SS) treatment. Wood samples were treated at different SS temperatures (140–180°C) for 1–3?h. The highest compression strength parallel-to-grain, hardness and impact strength were found for samples treated at 160°C for 3?h (30.7% higher than untreated), at 150°C for 1?h (26.6% higher than untreated) and at 150°C for 2?h (52.6% higher than untreated), respectively. The surface color became darker after each treatment in comparison with the untreated wood. The number of accessible hydroxyl groups decreased and the relative cellulose crystallinity increased with SS temperature, indicating decreased hygroscopicity of the treated wood. Also, SEM micrographs of wood surface showed consistent decrease in starch particles with treatment temperature. Both decay and termite resistances of treated rubberwood improved with treatment temperature. All the analyzes showed that dried rubberwood treated with SS had some improvements in the mechanical properties, decreased hygroscopicity, and increase resistance to decay. 相似文献
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为了使中纤板板面具有更好的色泽,增加销量,文章就如何提高中纤板表面白度进行了试验性研究。采用以草酸、漂白粉、VBL型荧光增白剂、双氧水为主剂的处理配方分别用涂刷的方法对小样中纤板表面进行增白试验,通过测定和分析处理效果发现,草酸、双氧水是适合中纤板板面增白的处理剂,综合考虑处理结果,以及成本和环保要求等因素,最后确定H2O2（27．5％）、NaOH（5％）、Na2SiO3（5％）以适当比例混合和浓度为5％的草酸为最佳中纤板板面增白配方。最后采用喷雾法用最佳处理配方对大样中纤板进行增白试验。结果表明,采用这两个配方对中纤板表面进行喷雾增白处理,白度分别可提高42．6％和17．5％,处理成本分别为127．11元／m^3和38．35元／m^3。 相似文献
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Experiments on alkaline hydrogen peroxide treatments with stepwise addition and oxygen pressurization were performed to determine whether they enhance the reaction between pulp components and hydroxyl radicals produced by the decomposition of hydrogen peroxide. In this study the degradation of methyl-dglucopyranoside (MGP), a model compound of pulp components, was an indicator of the progression of the reaction between pulp components and hydroxyl radicals. When comparing the degradation of MGP in the stepwise and one-time addition systems, MGP was degraded more in the stepwise addition system than in the one-time addition system when Fe3+ was added. This result indicates that the hydroxyl radical produced by the decomposition of hydrogen peroxide efficiently attacks MGP in the stepwise addition system. MGP was degraded to the same degree in the stepwise addition system as in the one-time addition system when Fe2+ or Mn2+ was added. Aggregation and precipitation of metal ions might affect their catalysis. Oxygen-pressurized hydrogen peroxide treatment caused almost no enhancement of the degradation of MGP compared to the treatment under atmospheric pressure. Instead, high stability of hydrogen peroxide was produced by oxygen-pressurized hydrogen peroxide treatment. Such high stability can result in frequent attacks of the hydroperoxide anion, the conjugate base of hydrogen peroxide, against some chromophores and quinones.Part of this paper was presented at the 1998 International Pulp Bleaching Conference, Helsinki, Finland 相似文献
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The objectives of this study were to search for appropriate chemical reagents without arsenic to use as green-color protectors for ma bamboo (Dendrocalamus latiflorus Munro) culms and to compare the effectiveness of these reagents for green-color conservation. Bamboo culms treated with chromated copper phosphate (CCP) or chromated phosphate (CP), which were developed by us, exhibit a greener color than those treated with Boliden K-33 (type B chromated copper arsenate).The experimental results revealed that among the chemicals employed, CrO3 and H3PO4 were key components in conserving the green color of bamboo epidermis, and their ratio definitely affected the effectiveness of green-color conservation. When the CrO3/H3PO4 ratio was 11, the treated bamboo culms displayed the greenest color. Among all the bamboo culms treated with different formulations of inorganic salts, the one treated with CP (1% CrO3, 1% H3PO4) had the best green-color conservation, enhanced by increasing the duration of treatment. 相似文献
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为改善圆竹的表面视觉性能，利用天然松香在不同温度下浸渍处理圆竹，采用定量色差和光泽度测量法结合感性眼动追踪法，评价了不同温度下松香处理对圆竹表面视觉特性的影响；利用扫描电镜和傅里叶红外分析探讨了松香对竹材表面视觉特性影响的机理。结果表明，对松香适当的加热有利于其在圆竹表面形成连续的薄膜，提高圆竹表面光泽度，当温度为50 ℃时达到最大光泽度19.6，比对照组提高了122.7%。同时伴随着处理温度的升高，圆竹表面亮度逐渐降低，并且颜色从黄绿区间逐渐向红蓝区间转变；此外当温度高于60 ℃时，圆竹皮层受损脱落，在圆竹表面形成条纹，并且条纹的密度随着处理温度的增加而增加。眼动追踪实验和主观评价结果表明，高光泽度会产生不适感，纯色表面受到大众的喜爱，而条纹表面的圆竹会受到小众的喜欢。 相似文献
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This study examined effects of surface modification with hydrogen peroxide (H2O2) on adhesive bond performance in birch veneer bonded with phenol–formaldehyde resin. The veneer was treated with 5% of H2O2 at 80 °C in the presence of alkali with the objective of improving adhesive bond performance and reducing the resin demand. The effects of the surface modification were determined by surface color measured with a spectrophotometer, bond performance tests with ABES (automated bonding evaluation system) and surface hydrophobicity with sessile contact angle measurements. Results demonstrated that veneer surface became significantly whiter, which also increased in lightness and decreased in redness and yellowness. ABES test revealed that a remarkable increase in bond performance in the treated veneer and the maximum bond strength with the treatment at 60 min, which was nearly twice as high as reference sample (5.42 → 9.94 N/mm2), was obtained. A notable decrease in contact angle measurements was also observed in the treated veneers (0° in 0.5 s). The surface modification of birch veneer with H2O2 + alkali demonstrated greater potential for the improvement of physical characteristics in veneer surface. Other aspects of H2O2 consumption during the treatment are also discussed. 相似文献