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1.
《Wood material science & engineering》2013,8(1):29-33
Abstract For most markets for wood, it is used without any treatments or modifications. When wood is used in adverse environments, it may be treated with chemicals to help prevent decay, improve water resistance, reduce the effects of ultraviolet radiation or increase fire retardancy. Many of these treatments involve the use of toxic or corrosive chemicals that can harm the environment. Chemical modification of wood provides an alternative by providing protection against water, decay, UV and thermal degradations by bonding chemicals to the cell wall polymers that do not leach out. Dimensional stability and decay resistance are two major properties that can be greatly improved by simple reactions with acetic anhydride. 相似文献
2.
We evaluated fungal decay and mold resistance, leaching, and water absorption of nano-compounds and Paraloid B72® (PB72) in treated wood specimens to develop new methods of consolidation by combining nano-particles and consolidants. Scots pine wood specimens were treated with dispersions of nano-CuO, nano-ZnO, nano-B2O3, nano-TiO2, and nano-CeO2. PB72 treatments of nano-particle-treated wood specimens were then carried out by either vacuum or immersion for 24 h. Previously, decayed wood specimens were also consolidated with the nano-compounds and PB72. PB72 treatments reduced element release from treated wood specimens. Nearly all nano-compounds + PB72 treatments increased the biological performance of treated wood specimens against decay fungi tested. PB72-only treated wood specimens had the highest weight losses in decay tests. No improvements were obtained in mold resistance tests when the nano-compounds and PB72 were combined. In nano-compound-only treatments, unleached specimens showed slightly lower water absorption values compared to untreated control specimens. Incorporation of PB72 into nano-compound-treated wood specimens resulted in considerably lower water absorption and volumetric swell. In previously decayed specimens treated with the nano-compounds and PB72 solution, water absorption after 2-h immersion declined compared to control specimens. 相似文献
3.
The formation of insoluble metaborates in wood was investigated by impregnating the wood with borax and metallic salts, after which their properties (e.g., leachability in running water and biological resistance) were evaluated. The solubility of three metaborates in acidic solutions was also evaluated. Double-diffusion treatment was carried out to form the precipitates of metaborates in sapwood specimens of Japanese cedar (Cryptomeria japonica) at room temperature. Water-saturated wood specimens were first impregnated by a saturated borax solution and then diffuse-penetrated with Zn2+, Ca2+, or Pb2+ solution. The precipitates of the three metaborates in the wood proved to be insoluble or hardly soluble in water by the leaching test. With the decay test using a brown-rot fungus (Fomitopsis palustris) and a white-rot fungus (Trametes versicolor) and with the termite test using a virulent subterranean termite (Coptotermes formosanus), the metaborate-treated woods showed generally good decay and termite resistance with negligible mass loss of the specimens. Particularly, the lead metaborate formed in the wood provided superb biological resistance against decay and termite attacks. In addition, the precipitates of these metaborates were found to be soluble in acidic solution, suggesting a way to remove these chemicals from wood when disposing of waste materials. 相似文献
4.
E. D. Gezer M. K. Yalinkilic K. Kizilkaya J. H. Michael 《Wood Science and Technology》1999,33(1):63-71
Summary This research illustrates a new procedure of analyzing data from soil- or agar-block decay tests using non-linear regression
techniques to estimate a toxic threshold retention point for wood preservative chemicals. The model can be used to provide
an objective estimate of the level of retention that is fully adequate, and can be applied satisfactorily to decay data from
laboratory decay tests. This so-called broken line model procedure analyzes the decay data simultaneously by separating it
into two different parts according to the threshold retention point. Such a procedure is preferable to previous methods which
suffer from the need of transforming decay data. Our analysis can be performed in any statistical analysis package that includes
a non-linear regression procedure, regardless of having a small or large data set, under the assumption that residuals are
normally distributed with a homogenous variance. The method of estimating weight loss due to decay and the one due to operational
procedure are also described.
Received 26 August 1997 相似文献
5.
If water stays on wood surfaces or is trapped in gaps, the wood is supplied with water for a long period of time and high local moisture contents are reached. This can lead to decay by rot fungi, and it is therefore important to avoid such water traps in order to limit the decay rate. This paper presents two methods: one for determination of duration of surface moisture on wood surfaces and one for determination of duration of water trapped in gaps in wood joints. Both these methods are based on electrical conductance measurements that are commonly used to measure moisture content of wood. Both sensor types consist of insulating tubing, electrically conductive adhesive and copper wire. The sensors monitor the presence of moisture on the actual material surface, and because of their small size, they do not influence the amount and duration of moisture that stays on the surface or in the gap. 相似文献
6.
H. Yamaguchi 《Wood Science and Technology》2002,36(5):399-417
A new wood preservative containing low molecular weight and low-toxicity silicic acid (LWSA) was investigated. To prevent
environmental pollution with the wood preservative, a silicic acid monomer aqueous solution (SAMS) or colloidal silicic acid
solution (CSAS) was combined with various metal compounds or boric acid. Agents where SAMS or CSAS was combined with boric
acid gave good protection against decay caused by the brown-rot fungus Fomitopsis palustris, the treated wood (Cryptomera japonica D. Don) specimens after the leaching test maintained a high resistance to decay. The leaching and decay tests revealed high
quantities of chemicals leaching from wood treated with SAMS-metal agents. However, when wood was treated with SAMS-boric
acid, there was little leaching of agent in either test. The mechanism of resistance of wood, which was treated with boric
acid mixed with CSAS or SAMS, to the brown-rot fungus F. palustris were investigated. When the concentration of boric acid was high, mycelial growth was inhibited completely and no protein
production was detected. When the amount of boric acid was low, the xylanase, mannase and cellulase activities were lower
than with control wood powder. When powdery boric acid was combined with CSAS, it was considered that the treated woods have
higher anti-weather properties than when boric acid-methanol solution was mixed with CSAS. The agent-preparation method adopted
should be considered carefully after taking the treatment process and the intended use of the preservative-treated wood into
account.
Received 26 September 2000
This study was supported by a Grant-in-Aid (09460079) for Scientific Research from the Ministry of Education, Science, and
Culture of Japan. 相似文献
7.
Chromated copper arsenate (CCA) is the primary wood preservative used in the United States. CCA products are used for decking, fencing, retaining walls, docks, poles, and highway sign posts. Since CCA became popular in the early 1970's, it is estimated that over 140 million cubic meters of these products are in service. Although the EPA allows disposal of spent CCA products in landfills, increasingly they are looking at the possibility of restricting its disposal. One method for potential re-use of CCA treated wood fiber would be to remove the treatment chemicals and process the fiber into energy or consumer products. The objectives of this research were to determine which method(s) can improve the removal of copper, chromium, and arsenate from spent CCA-treated lumber. The best material, in this research, for leaching chemicals from treated wood with organic acids, were particles (compared to chips and steam exploded wood). Without the functions of organic acids, the best method to remove chemicals proved to be steam explosion and further extraction by water. Citric acid was the most effective acid used in the removal of treatment chemicals of the three acids evaluated: acetic, citric, and sulfuric. The time effect on the extraction process indicated that most of the treatment chemicals were removed within the first seven days of treatment. This study also indicates that steam explosion does not increase the extractability of the chemical components. Other methods need to be examined which may lead to better removal of the chemicals or more effective methods to recycle spent CCA products. 相似文献
8.
文章以马尾松、尾叶桉、马占相思和南洋楹4种木材为研究对象,采用KJQ、TRQ、WAQ 3种涂料与防腐剂复配处理木材,研究复配涂料对木材耐腐性能的影响。结果表明KJQ复配涂料处理对提高马尾松的耐腐性能较其它2种涂料好。经KJQ复配涂料处理后,马尾松、尾叶桉、马占相思和南洋楹木材的耐腐性能由原来的稍耐腐等级提高到强耐腐等级,其中KJQ涂料与DDAC、IPBC和SGB 3种防腐剂活性成分复配后的处理材耐腐性能较好。 相似文献
9.
对新伐巴尾松剥皮或不剥皮原木喷以多种化学药剂进行了防腐、防虫试验研究、证明杀虫效果较好的有辛硫磷、倍硫磷和林丹，防腐效果较好的有6781、6782、6783、6784、FCAP、AC3B等；其中6781、6782能使剥皮尾松原木露天存放二年材质完好如新。枫香和拟赤扬剥皮原木喷药后棚内干存效果较好，但露天存放效果较差。锯材（厚板）瞬浸处理后棚内干存一年不霉不腐。 相似文献
10.
木塑复合材料耐候性能研究进展 总被引：1，自引：0，他引：1
木塑复合材料(WPC)的耐候性能决定了材料的户外使用寿命。文中介绍了国内外在WPC耐热氧老化、耐光氧老化、耐真菌腐朽及耐潮湿与冻融性能方面的研究进展。现有研究表明, 热氧老化与光氧老化均使得WPC发生褪色现象, 力学性能下降, 添加抗氧化剂与光稳定剂可分别改善二者对WPC的破坏作用。WPC中木粉含量较高时更易发生真菌腐朽现象, 添加化学防腐剂或其他助剂、木粉改性及涂饰可有效抑制真菌腐朽。WPC的吸水性是其热氧老化、光氧老化、真菌腐朽及冻融循环过程的催化剂。文中还总结了目前WPC耐候性能研究存在的主要问题, 并对其未来趋势进行了展望。 相似文献
11.
Sandor Poncsak Duygu Kocaefe Ramdane Younsi Yasar Kocaefe Louis Gastonguay 《Wood Science and Technology》2009,43(5-6):471-486
Thermal treatment is used to preserve the wood without any addition of any toxic chemicals. This process increases the dimensional stability and darkens the color of the wood. The improvement of the resistance to decay of wood by thermal treatment is also often suggested in the literature. However, some latest works contested if the durability of heat-treated wood is improved when it is used in contact with ground. The objective of this study was to investigate the possibility of thermally treating electrical poles which are larger compared to the standard wood lumber. One of the applications for thermally treated wood poles could be their use in environmental sensitive areas (along rivers, for example) as a replacement for untreated western red cedar (WRC) poles which are more expensive. Green and pre-dried red pine (Pinus resinosa) and jack pine (Pinus banksiana) poles, both with circular and square cross-sections, were heated to high temperatures under humid and inert atmosphere. Operating parameters such as maximum treatment temperature, maintenance time at this temperature, heating rate and gas humidity were varied in order to find most suitable treatment conditions for the poles. The tests showed that most of the cracks are formed during the drying process while thermal treatment only widened already existing cracks. The circular shape seems to promote crack formation during the drying period since the directional dependence of shrinking creates more stresses in circular poles compared to the square poles. A slight decrease in flexibility of the wood with increasing temperatures was observed. The protecting effect of gas humidity against oxidation of wood and the importance of the application of a moderate heating rate for poles with large cross-sections are also demonstrated in this article. The impact of the heat treatment on the resistance to decay of electrical wood pole will be presented in a future publication. 相似文献
12.
13.
S. Nami Kartal Christian Brischke Andreas O. Rapp Yuji Imamura 《Wood Science and Technology》2006,40(1):63-71
Evaluation of wood preservatives in soil-contact tests is becoming an important issue since detoxification of wood-protecting
compounds by fungi and bacteria found in soil may decrease the resistance of treated wood. In this study, the decay resistance
of wood treated with didecyl dimethyl ammonium tetrafluoroborate (DBF), a recently developed quaternary ammonia compound,
was evaluated in both soil bed and laboratory decay resistance tests. Small specimens (5×10×100 mm3) of DBF-treated and untreated sugi sapwood were subjected to decay in laboratory soil bed tests (DIN ENV 807 (2001)) followed
by Basidiomycetes tests (DIN EN 113 (1996)). Exposure in field soil and compost soil substrates was used to observe the effects
of wood degrading and other soil-inhabiting micro-organisms on the decay resistance of the specimens. Soil bed tests showed
that DBF-treated wood specimens at 7.7 kg/m3 retention level (1% DBF solution concentration) showed better performance compared to 0.01 and 0.1% DBF treatments. The 7.7 kg/m3 retention level was also effective to protect the wood specimens against Coniophora puteana and Coriolus versicolor in Basidiomycetes tests. It is concluded that detoxification of wood preservatives in soil contact is an important factor
to determine protective properties of treated wood in ground contact applications. Further experiments with larger specimens
are needed to observe the performance of DBF-treated wood at higher retention levels in field above ground and ground contact
tests.
Dedicated to Prof. Dr. H.C. Mult. Walter Liese on the occasion of his 80th birthday. 相似文献
14.
For overcoming disadvantages of wood, an esterification process was employed and tetrabromophthalic anhydride (TBPA) was used as a reactive chemical agent to prepare an esterified wood with the high dimensional stability, flame resistance, and resistance to biodegradation from water-leaching. The experimental results indicated that esterification of wood plus maleic anhydride / tetrabromophthalic anhydride / glycerol could endow wood with dimensional stability, the antiswelling efficiency during water absorption (ASEw), reduction in water absorptivity (RWA), antiswelling efficiency during moisture absorption (ASEm),moisture excluding efficiency (MEE), and oxygen index (OI) of treated wood increased with an increase in the weight percent gain(WPG). And the treated wood showed great decay resistance and resistance to water leaching, too. 相似文献
15.
Sye Hee Ahn Sei Chang Oh In-Gyu Choi Ho-Yong Kim In Yang 《Journal of Wood Science》2008,54(6):495-501
As a substitute for high-cost copper azole (CuAz) and alkaline copper quaternary (ACQ) wood preservatives, alternative wood
preservatives were formulated with okara, which is an organic waste from the production of tofu, and copper chloride and/or
borax. Each preservative was used in treatment of wood blocks in a reduced-pressure method to measure its treatability. The
treated wood blocks were placed in hot water for 3 days to examine the stability of the preservatives against hot-water leaching.
The preservatives successfully penetrated into wood blocks, probably due to the use of ammonium hydroxide as a dissociating
agent. However, the stability of okara-based preservatives dropped as the concentration of acid in the solutions used for
hydrolysis of okara increased. The treatability and leachability of the preservatives were not affected by hydrolysis temperature
but were negatively affected by the addition of borax. Leached wood blocks treated with okara-based preservatives and exposed
to decay fungi Gloeophyllum trabeum and Postia placenta over 12 weeks showed good decay resistance. Okara-based wood preservatives can protect wood against fungal attack as effectively
as CuAz, and have potential for use as environmentally friendly wood preservatives. 相似文献
16.
G. C. Chen 《Wood Science and Technology》1994,28(5):365-370
Summary We are investigating wood decay biocides that are both effective in protecting wood from decay and more environmentally compatible than other biocides. A series of halophenyl sulfonamides were synthesized and characterized by infrared and neuclear magnetic resonance spectroscopy. Wood impregnated with these compounds was tested for resistance to decay as well as water leaching. Wood impregnated with para-iodophenyl or para-fluorophenyl para-tolyl sulfonamides resisted decay by brown- and white-rot fungi. For wood impregnated with para-iodophenyl para-tolyl sulfonamide, threshold retention with the brown-rot fungus Gloeophyllum trabeum was 9.1 mmol/ 100 g solution for unleached blocks. For leached blocks, weight loss was very high (24.6%), which indicated that threshold retention will be substantially higher than 9.1 mmol/100 g solution. With the white-rot fungus Coriolus versicolor, threshold retentions were 2.9 and 5.6 mmol/100 g solution, respectively, for unleached and leached blocks. Leaching of the blocks treated with the iodo compound slightly decreased resistance to decay by C. versicolor. For wood impregnated with parafluorophenyl para-tolyl sulfonamide, threshold retentions with both G. trabeum and C. versicolor were very close to 9.0 and 9.2 mmol/100 g solution, respectively, for leached and unleached blocks. Leaching had a little effect on resistance to decay by both fungi. Wood impregnated with parachlorophenyl or bromophenyl para-tolyl sulfonamide was ineffective in resisting decay by both fungi. 相似文献
17.
Sheikh Ali Ahmed Tom Morén Margot Sehlstedt-Persson Åsa Blom 《Journal of Wood Science》2017,63(1):74-82
Conventional chemical wood preservatives have been banned or restricted in some applications due to human and animal toxicity and their adverse impact on the surrounding environment. New, low-environmental-impact wood treatments that still provide effective protection systems are needed to protect wood. Thermal modification of wood could reduce hygroscopicity, improve dimensional stability and enhance resistance to mold attack. The aim of this study was to investigate if these properties enhanced in thermally modified (TM) wood through treatments with oils. In this study, TM European aspen (Populus tremula) and downy birch (Betula pubescens) wood were impregnated with three different types of oil: water-miscible commercial Elit Träskydd (Beckers oil with propiconazole and 3-iodo-2-propynyl butylcarbamate, IPBC), a pine tar formulation and 100% tung oil. The properties of oil-impregnated wood investigated were water repellency, dimensional stability and mold susceptibility. The treated wood, especially with pine tar and tung oil, showed an increase in water repellency and dimensional stability. However, Beckers oil which contains biocides like propiconazole and IPBC showed better protection against mold compared with pine tar and tung oil. To enhance the dimensional stability of the wood, pine tar and tung oil can be used, but these oil treatments did not significantly improve mold resistance rather sometimes enhanced the mold growth, whereas a significant anti-mold effect was observed on Beckers oil treated samples. 相似文献
18.
ＣＣＢ是一种性能优良的木材防腐剂，但它的抗流失性能不如ＣＣＡ，由于它是水溶性防腐剂，故处理后木材的尺寸亦不稳定。本研究采用在防腐剂中添加聚合物或树脂的方法来提高ＣＣＢ的抗流失性能，使ＣＣＢ处理材的尺寸稳定性大大提高。研究结果表明，在ＣＣＢ中添加少量聚乙烯醇缩醛树脂后，铜、铬、硼的流失与不加树脂相比分别减少５７．６３，７８．５３和９６，４６％；木材湿胀性在弦向减少９１．９７％、径向减少８８．３４％、体积减少８４，２０％；处理材的抗腐力也明显提高。 相似文献
19.
Ping-Sheng Chen Yu-Han Chen Ting-Feng Yeh Shang-Tzen Chang 《Wood Science and Technology》2014,48(3):451-465
Acacia confusa is an indigenous plantation species in Taiwan, and its heartwood has excellent decay resistance capability. The aim of this study is to investigate the resistance mechanisms of heartwood extracts from A. confusa against Laetiporus sulphureus (brown-rot). Results from wood block decay resistance tests indicate that aqueous crude extract and its three soluble fractions can significantly decrease the weight loss of wood blocks caused by L. sulphureus. However, none of the extracts can inhibit the growth of L. sulphureus on agar plate test. The performance of decay resistance from three soluble fractions is consistent with their antioxidant activities (DPPH free radical scavenging activity, reducing power and ferrous ion chelating ability). 3,4-Dihydroxybenzoic acid (3,4-DHBA), the compound present in three soluble fractions, exhibited excellent antioxidant activities and was proven to have excellent decay resistance ability against L. sulphureus. These findings suggest that 3,4-DHBA may be responsible for the inhibition of hydroxyl radical formation from Fenton reaction caused by L. sulphureus. Thus, 3,4-DHBA has good potential to be used as a novel and environmentally benign wood preservative. 相似文献
20.
基于应力波与X射线二维CT图像原木内部腐朽无损检测 总被引：3，自引：0，他引：3
木材无损检测技术是在20世纪60年代后逐步兴起的对木材性质进行非破坏性检测的技术,如今该技术已多达几十种,产生了多种多样的木材无损检测方法。为了更好地运用这些方法,找出它们的优缺点,有必要对它们检测木材内部缺陷进行试验和评价。同时使用应力波和X射线两种方法对原木内部腐朽进行检测,结果表明：应力波和X射线二维CT图像都能检测出原木内部腐朽,显示出腐朽的区域,而且能利用图像计算出腐朽区域的面积。两种方法计算出的腐朽区域的面积准确度φ都较高,但是应力波二维CT图像在其他许多方面逊于X射线二维CT图像：应力波二维CT图像对腐朽区域形状的显示不够准确,不能根据图像辨别出腐朽的严重程度,利用图像确定腐朽面积效率很低;X射线二维CT图像对腐朽区域形状的显示与实际较吻合,可以根据图像辨别出腐朽的严重程度,利用图像确定腐朽面积效率高。但是X射线仪器笨重不便携,而应力波检测仪轻快便携。 相似文献