Resistance of Scots pine (Pinus sylvestris L.) wood modified with functionalized commercial silicone emulsions against subterranean termites

Scots pine (Pinus sylvestris L.) sapwood was treated with quat-silicone micro-emulsion (<40?nm), amino-silicone macro-emulsion (110?nm), alkyl-modified silicone macro-emulsion (740?nm) and solutions of inorganic water glass. Three treatment concentrations of 5, 15 and 30% (w/w) were used for the impregnation of the test specimens. Termite resistance was assessed following a 16-week field trial conducted in northern Queensland, Australia. Two different field sites were chosen for exposure to feeding by Coptotermes acinaciformis (Froggatt) and Mastotermes darwiniensis (Froggatt). Following exposure, the test and feeder specimens were inspected and assessed for termite damage using a visual rating system (from 10 sound to 0 completely destroyed) and individual mass losses. The specimens treated with quat- and amino-silicone emulsions resisted damage by both termite species, even at less than 15% weight percent gains (WPGs). Alkyl-modified silicone macro-emulsion and water glass treatment induced somewhat less resistance to termite damage, but imparted protection at higher WPGs.     

Leachability,decay, and termite resistance of wood treated with metaborates

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.     

高温热改性橡胶木的生物耐久性

以水蒸气作为保护气体,在170,185,200和215℃的条件下分别热处理橡胶木3h,对热改性橡胶木的生物耐久性进行研究.结果显示:高温热改性可提高橡胶木的耐腐性,其改善效果随着处理温度的升高而提高,当处理温度为185℃或更低温度时,改善效果不明显.215℃处理3h后,褐腐(密黏褶菌)质量损失率由51.6％降至21.6％,白腐(采绒革盖菌)质量损失率由27.6％降至6.8％.选用烟曲霉、哈茨木霉、产紫青霉和可可球二孢进行防霉试验,结果显示热改性橡胶木的防霉性能与对照相比没有明显的改善;经涂饰后,热改性试材的防霉性能优于未处理材.野外耐久性试验结果显示,高温热改性不能提高橡胶木的防白蚁性能.     

几种防腐剂处理的马尾松材室内抗家白蚁（Coptotermes formosanus Shiraki）效果试验

利用三种防腐剂处理后的马尾松（Pinus massoniana Lamb．）边材在室内接种家白蚁（Coptotermes formosanus Shiraki）以测试其抗蚁蛀能力。这三种防腐剂包括含砷铬类防腐剂铜铬砷（CCA）和两种非含砷铬类防腐剂柠檬酸铜（CC）、季铵铜（ACQ）。测试一个月后的结果表明,三种防腐剂的各个测试浓度的抗蚁蛀效果很好,试块的失重均不超过5％。经方差分析及平均数多重比较结果表明,三种防腐剂不同处理浓度与对照间试块的实际失重的差异以及白蚁存活率的差异均达显著水平（P〈0．05）。CCA防腐剂在0．05％～1．00％浓度（实际吸药量0．60～6．07kg／m^3）处理下,白蚁全部死亡,试块表面被轻度蛀食。CC与ACQ防腐剂的抗蚁蛀效果很相似,在0．6％～2．0％高浓度（实际吸药量分别为3．94～12．90kg／m^3和3．04—9．92kg／m^3）下,白蚁全部死亡,试块未被白蚁蛀食,完好无损;但在0．2％～0．4％低浓度（实际吸药量〈3kg／m^3）下有部分白蚁存活,试块被白蚁轻度或中度蛀食;低浓度组与高浓度组之间白蚁存活率的差异达显著或极显著水平。从白蚁存活率、试块的失重及试块抗蚁蛀等级综合分析结果表明,经CCA、CC、ACQ三种防腐剂处理后的马尾松木材的抗蚁蛀能力明显提高。     

化学处理法对竹材阻燃、抗菌和防腐的影响(英文)

研究了6种用于印度勒竹防护的制剂,主要用于阻燃、防火防腐、抗真菌和白蚁的腐蚀。考察了阻燃剂和新型环保防腐剂ZiBOC用于印度勒竹防护的协同作用。将裂开的竹片用质量分数为15%的6种防护组分处理,即按照印度标准方法测试火焰穿透性、可燃性和燃烧率。6种15%质量分数的组分分别为:1.硫酸铵+磷酸铵+ZiBOC;2.硫酸铵+ZiBOC;3.磷酸铵+ZiBOC;4.磷酸镁+焦硫酸镁+ZiBOC;5.磷酸镁+ZiBOC;6.焦磷酸镁+ZiBOC。结果表明,达到防护目的的不同化学组分的防护剂用量应为9～11.5kg/m3。用白腐菌的腐烂实验表明,配方为2、3、5和6的防护剂表现出较好的防腐作用(防护率达到95%,p0.05),而用褐腐菌其防护率约为43%～67%。采用经2～6配方处理过的样品均能抗第一、二期的白腐腐蚀,而第二期的白蚁对配方4处理过的样品有轻微的腐蚀作用。少数几种配方对材料的耐火性有提高。     

Silicic acid: boric acid complexes as wood preservatives

Wood was treated with a low molecular-weight silicic acid: boric acid agent and examined for increased resistance to termites and combustion. Wood treated with silicic acid only exhibited increased termite resistance, but not to the marked extent observed after treatment with a mixture of silicic and boric acids. Increasing the quantity of boric acid also increased the termite mortality rate and shortened the time to death. Oral-toxicity tests using dyed silicic acid: boric acid suggested that the boric acid in the agent acted as a stomach poison. Field tests on stakes over three years showed that even if stakes were placed near the termite exit, those treated with silicic acid and high levels of boric acid had no attack by termites and maintained their original form. Though these specimens were installed in the field during three rainy seasons (about six months in total) in three years, the termite resistance ability of these chemicals was maintained. It became clear that this silicic acid: boric acid agent has a high water resistance ability worthy of application in the outdoors. Combustion tests showed that flame and glowing combustion times were shortened at high levels of boric acid. When a boric acid: methanol solution was added at of rate of not less than 25 ml for 100 g of colloidal silicic acid solution (CSAS), flaming and glowing combustion were not observed. Although the charring length of the wood specimen which was treated with a low molecular weight silicic acid: boric acid agent decreased to 2/3 of that of the control wood, the charring lengths were not influenced by the level of boric acid. However, the volume of smoke decreased relative to the amount of boric acid that had been added.     

Comparative effectiveness of two alkylammonium compounds as wood preservatives

This study describes a laboratory evaluation of the efficacy of two alkylammonium compounds [didecyldimethylammonium tetrafluoroborate (DBF) and didecyldimethylammonium chloride (DDAC)] when applied via vacuum impregnation or superficial treatment. Treated wood specimens were tested for their termite and microbial resistance under controlled laboratory conditions. The higher chemical retentions were needed to suppress the feeding by Coptotermes formosanus ≦3% mass loss in the multichoice test than in the no-choice test. The DBF and DDAC retention levels necessary to meet the performance requirement ≦3% mass loss after 12-week fungal exposure varied with wood species. The retention level of 3 kg/m³ for DBF and DDAC was generally high to keep the nondurable wood species free of decay. Although there was no difference between DBF and DDAC in the efficacy against decay and termite attack, the former slightly outperformed the latter as an antimold and antisapstain agent.     

白蚁诱饵剂成型工艺的研究

我国在 2 0世纪 70年代后期开始研制毒饵来诱杀白蚁 ,同时对毒饵的型式也进行了一定的研究 (江西永修县林业科学研究所 ,1979)。 1985年 ,原中国白蚁防治科技协作中心 ,协调、组织地方各级白蚁防治研究所共同研制出了银耳真菌腐木屑胶冻剂、蜂粉膏剂、纸袋粉剂和纸块 (管 )剂 (黄远达 ,2 0 0 1)。林树青 (1993)在研制中草药诱饵剂的过程中 ,进行了诱饵剂包装材料的筛选 ,并把中草药诱饵剂制成了诱饵包。罗均泽等(1988)、何复梅等 (1997)和佘春仁等 (1999)利用白蚁踪迹信息素及其类似物与灭蚁灵等药剂混合分别制成了诱杀包、诱杀块等型诱饵。…     

Termite resistance of beech wood treated with zinc oxide and zinc borate nanocompounds*

The field of wood protection is currently changing due to the restrictions imposed by the Biocidal Products Regulation. The need for development of new wood protection technologies is therefore growing. In this work, the resistance of European beech (Fagus sylvatica L.) wood impregnated with nano-dispersions of zinc oxide (nano-ZnO) and zinc borate (nano-ZnB) against the termite Reticulitermes grassei Clement was investigated. Three different concentrations (0.5%, 1%, 2%) of the nanocompounds were tested. The effects of water leaching were also investigated. A severe effect in terms of termite workers mortality was induced by both dispersions, even at the lowest concentration. In terms of termite feeding, nano-ZnO dispersions appeared to be more efficient than nano-ZnB as they induced significant improvement at concentrations as low as 0.5%. Nano-ZnB was applied at 1% or higher concentrations in order to impart similar changes. Nano-ZnB dispersions were efficient in terms of termite resistance for a concentration at least 1%. Further increasing concentration to 2% resulted in a respective increase of wood efficacy against termites. For both tested nanocompounds, water leaching did not result in any significant increase of termite feeding.     

Laboratory evaluation of the termiticidal efficacy of copper HDO

A laboratory no-choice termite bioassay was conducted to evaluate the ability of copper HDO (CX-A or copper xyligen) to protect radiata pine (Pinus radiata D. Don) wood samples from attack by two subterranean termite species, Reticulitermes speratus and Coptotermes formosanus. A series of sapwood samples were pressure treated with either 0.25%, 0.50%, 0.75%, or 1.00% copper HDO solution. Samples treated with equivalent concentrations of a benchmark preservative, CCA-C, were used as treated controls. All samples (including controls) were subjected to an artificial weathering schedule before the bioassay. The samples were exposed to 30-day R. speratus tests and 3-week C. formosanus tests. Copper HDO was shown to deter termites from significant feeding on the treated wood. At a retention of 5.8 kg/m3 (treated with 0.75% solution) or higher, the mass loss from termite feeding did not exceed 3% for both the 30-day R. speratus tests and the 3-week C. formosanus tests. At each of the retentions tested, copper HDO performed comparably with equivalent retentions of CCA-C; however, field data are needed to validate these laboratory results. The preliminary findings are that copper HDO pressure treatment has potential as a viable method of protecting wood from attack by both termite species tested.     

Feeding responses of the western dry-wood termite <Emphasis Type="Italic">Incisitermes minor</Emphasis> (Hagen) (Isoptera: Kalotermitidae) against ten commercial timbers

Five Japanese timbers, four timbers from the USA, and one Malaysian timber were evaluated for their resistance to the invasive dry-wood termite Incisitermes minor (Hagen) using laboratory choice and no-choice feeding tests with holed specimens. The highest survival rates of I. minor in both the heartwood and sapwood no-choice feeding tests were more than 70% after 3 months. When offered sapwood and heartwood choice feeding tests and the combined choice feeding tests, the highest survival rates of I. minor were more than 75% after 3 months. With regards to the percentage of wood mass losses in the no-choice and choice feeding tests, karamatsu (Larix leptolepsis), buna (Fagus crenata), and Douglas fir (Pseudotsuga menziesii) were classified as “resistant” species among the ten sapwood specimens. In the heartwood no-choice and choice feeding tests, the resistant species were buna, karamatsu, Douglas fir, sugi (Cryptomeria japonica), akamatsu (Pinus densiflora), and western red cedar (Thuja plicata). The ranking of the resistance of the ten commercial timbers against I. minor was buna > karamatsu > sugi > western red cedar > Douglas fir > rubber > western hemlock > hinoki > spruce.     

Biological performance of particleboard incorporated with boron minerals

We compared resistance to decay, mold fungi,termites and insect larvae of particleboards incorporated with the raw boron minerals ulexite and colemanite to that of particleboards impregnated with the commercial boron preservative zinc borate, or boric acid plus a borax mixture.We also quantified water absorption, thickness swell and boron release of particleboards. Ulexite had the best decay resistance, and colemanite had the best termite resistance.However, ulexite and colemanite were not as effective as zinc borate or the boric acid/borax mixture in preventing mold growth. In general, the boric acid/borax mixture combination was more effective against Anobium larvae than the other treatments. Less boron was released by specimens containing zinc borate and colemanite than bythose containing ulexite or the boric acid/borax mixture. In general, water absorption and thickness swell were similar among the different treatments, but both were slightly higher in the ulexite-incorporated specimens. Further mechanical tests will be needed to evaluate the particleboard properties and thereby the compatibility of these boron minerals with various manufacturing processes.     

Efficacy of didecyldimethylammonium chloride against subterranean termites (Isoptera) in Australia

A laboratory bioassay was conducted on the ability of didecyldimethylammonium chloride (DDAC) to protectPinus radiata D. Don wood specimens from attack by two of Australia's most economically important species of subterranean termite,Mastotermes darwiniensis Froggatt (Mastotermitidae) andCoptotermes acinaciformis (Froggatt) (Rhinotermitidae). Sapwood specimens ofP. radiata, treated to achieve nominal retentions of 0.5, 1.0, 2.0, 4.0 and 6.0 kg/m³ of active ingredient, were bioassayed against each of these termite species for four and eight weeks, respectively. Mean percentage mass loss data showed that between 2.0 and 4.0 kg/m³ of DDAC was necessary to protect specimens from significant attack by both species of termite. The usefulness of DDAC as a termiticide for timber, particularly in the above-ground situation, is discussed.With one table and one figure     

Zur Wirkung von Bacillus thuringiensis var. israelensis auf die Larven der Stechmücke Culex pipiens molestus

Laboratory infectivity tests were undertaken to investigate the pathogenicity of “Bactimos” (a new commerical bacterial biocide) aginst different instar larvae ofCulex pipiens molestus. The biocide “Bactimos”,Bacillus thuringiensis var.israelensis, was confirmed as pathogenic for mosquito larvae ofC. pipiens molestus. At dosage of 0.000125 mg/250 ml water, mortalities of 25, 98, and 97% were recorded for the 1st, 2nd and 3rd instar larvae after 24 hrs, respectively. Dosage of 0.008 mg/250 ml water proved to kill all types of instar larvae (100% mortality) after 24 hours. Water volumes ranging from 100 to 800 ml, containing 0.005 mg “Bactimos” per each were found to kill the 2nd and 4th instar larvae (90–100% mortality) with no significant differences. In conclusion, it is quite evident that the commerical bacterialbiocide “Bactimos” should be recommended as biomortality agent against mosquito larvae in Upper Egypt.     

Biological performance,water absorption,and swelling of wood treated with nano-particles combined with the application of Paraloid B72<Superscript>®</Superscript>

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.     

Biological effectiveness of didecyl dimethyl ammonium tetrafluoroborate (DBF) against basidiomycetes following preconditioning in soil bed tests

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.     

Enhancement of the biological resistance of wood by phenylboronic acid treatment

Phenylboronic acid (PBA) was tested in terms of boron leachability from treated wood. In addition, the fungal and termiticidal efficacy of PBA-impregnated sugi (Cryptomeria japonica D. Don) wood was tested against the decay fungi Coriolus versicolor (L. ex Fr.) Quel. and Tyromyces palustris (Berk. et Curt) Murr., representing white-rot and brown-rot fungi, respectively, and the Formosan subterranean termite Coptotermes formosanus Shiraki. Ion chromatography analysis of hot water extracts of treated wood before and after leaching indicated that PBA is considerably resistant to water leaching, and saturation of the treatment solution increased the fixation ratio of boron in wood, whereas boric acid could not remain in wood impregnated even with the saturated solution. Decay test results revealed the excellent bioactive performance of PBA. Wood treated with 0.34% PBA solution was found resistant to both decay fungi, even after running-water leaching for 10 days and treatment with 1.00% PBA completely inactivated the Formosan subterranean termite for the leached specimens. Weight gain levels were 0.18% w/w (0.46kg/m³) and 0.99% w/w (2.49kg/m³) for these concentration levels, respectively, after being leached by running water. Contrary to the general belief that boron is a slow-acting toxicant against termites and unable to prevent mass loss of treated wood, PBA acted rapidly, and the mass loss caused by termites was low.This study was presented in part at the 47th annual meeting of the Japan Wood Research Society, Kochi, April, 1997     

Strength,decay and termite resistance of oriented kenaf fiberboards

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.     

Superheated steam treatment of rubberwood to enhance its mechanical,physiochemical, and biological properties

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.     

Termite resistance and wood-penetrability of chemically modified tannin and tannin-copper complexes as wood preservatives

We examined the ability of chemically modified tannin and tannin-copper complexes to penetrate wood and the ability of the treated wood to resist termites. Only the tannin-treated wood retained the agents after treatment. Wood with untreated mimosa tannin (MT) retained the least amount, followed by wood with resorcinolated tannin (RMT) and that with catecholated tannin (CMT). When RMT or CMT was mixed with ammonia-copper, the wood retained twice as much of these solutions as the MT -ammonia-copper solution. The degree of retention of RMT-NH₃-Cu and CMT-NH₃-Cu ranged from 268 to 326kg/m³. The solutions penetrated 2–13 mm from the tangential sections of the logs. We also measured the termite resistance conferred by these solutions. Most of the tannin-NH₃-Cu solutions showed contact lethality for termites in the contact toxicity test. However, the termites were fed cellulose treated with those solutions and most survived the oral toxicity test (14 days). Moreover, these solutions reduced the amount of damage to the wood by termites. However, the mortality rate of the termites during the eating-damage test (>21 days) did not reach 100% for any of the solutions except for RMT. As a result of the field stake test with the same log's used for the penetrability test, the mass loss of wood treated with RMT or CMT alone or with RMT + NH₃ + CuCl₂, was about one-third to one-half that of the controls. Because these solutions have good wood penetrability and good termite resistance, they have potential use as low-toxicity wood preservatives.