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New Method for Pretreatment of Railroad Crossties
2014 - IRG/WP 14-40675
Creosote has been successfully utilized for nearly 150 years for the protection of railroad crossties (sleepers) in the USA and remains today as the most widely used wood preservative for this application. One of the few shortcomings of creosote as a preservative is its inability to penetrate many of the refractory hardwood species which make up the majority of crossties in the USA. Lack of full penetration often leaves the cores of these ties unprotected, making them vulnerable to attack by decay fungi and termites. As a result, service life can be significantly reduced, particularly in the Southeast and Gulf Coast regions of the USA. Twenty-Five years ago, Amburgey and Williams addressed this need through the development of a dual treatment for crossties consisting of an initial dip pretreatment with borates (e.g., DOT) followed by a period of diffusion, then another period of seasoning, and finally a conventional pressure treatment with creosote. The treatment resulted in a borate-treated core surrounded by a creosote-treated shell. It performed well, as evidenced by 20 years’ worth of field data showing a meaningful increase in service life of dual-treated ties over conventional creosote-treated ties. However, the inefficiencies of the Amburgey/Williams dual treatment process, encompassing long storage periods of ties during the diffusion and seasoning steps, have limited its commercial utilization. This paper describes a new method for pretreatment of crossties which greatly improves the efficiency of the original dual treatment process while achieving the same borate and creosote penetrations and retentions which were shown to perform well in 20 years of field data. The new process is a chemically-based technology which utilizes a Buffered Amine Oxide carrier to penetrate the cellular structure of wood and deposit and bind wood protection chemicals such as borates and carbon based insecticides deep into the core of substrates including refractory species. The new process was introduced commercially in 2010 and has since been used to treat over 10 million crossties for Class I railroads in the United States.
A S Ross, R W Clawson Jr


Buffered Amine Oxide Treatment Systems for Ammonical Copper Wood Preservatives
2014 - IRG/WP 14-40685
Wood is the most versatile, practical and sustainable building material in the world. In modern countries, wood is a well-managed renewable resource that has a small carbon footprint. Wood does suffer from a lack of durability against invasive organisms such as insects and fungi. Steel, aluminum and composites have emerged as viable alternative building materials. These sectors market the deficiencies of wood to better position their products. As these materials continue to take market share away from wood, the need to cost-effectively increase the durability of wood remains an always present target within the forest products industry. The use of chemical treatments to impart fungal and insect resistance into wood has been utilized for over a century. Today, many of these preservatives are delivered into the wood using the same decades-old methods and chemicals. The development of buffered amine oxides treatment systems (known commercially as TRU-CORE® Technology) for use in wood preservation has allowed significant modernization of the application and preservation process. The buffered amine oxides allow for a chemically based infusion process that is capable of delivering key wood protectants completely throughout the wood. This waterbased system imparts a minimal amount of added moisture into the wood during the process, so there is no need to dry after treatment. A short activation period is utilized to achieve full penetration. For larger wood profiles, such as decking members and railroad crossties, the use of pressure/vacuum impregnation accelerates the penetration. The Buffered Amine Oxide Treatment System is in commercial use in the United States, New Zealand and Australia; where numerous programs have been developed for residential and industrial wood products. The most modern buffered amine oxide treatment system was designed to impart ammonical copper based wood preservatives into decking profiles.
R W Clawson Jr


Buffered Amine Oxide Treatment Systems for Imparting Water Based Azoles/Insecticides in Douglas Fir and Eucalyptus
2015 - IRG/WP 15-40707
In today’s world, wood remains the most versatile, practical and sustainable building material. In contemporary countries, wood is a well-managed renewable resource that has a remarkably small carbon footprint compared to those of steel, aluminium, composites, and concrete. These alternative materials have continued to emerge as viable building materials given the durability issues of untreated wood against attack from insects and fungi. As these materials continue to take market share away from wood, the need to cost-effectively increase the durability of wood remains an always present target within the forest products industry. The use of chemical treatments to impart fungal and insect resistance into wood has been utilized for over a century. Today, many of these preservatives are delivered into the wood using the same decades-old methods and chemicals, including the utilization of emission-prohibitive organic solvent based delivery systems. The development of solvent-free, Water Based Buffered Amine Oxide Treatment Systems (known commercially as TRU-CORE® Technology) for use in wood preservation has allowed significant modernization of the application and preservation process. The buffered amine oxides allow for a chemically based infusion process that is capable of delivering key wood protectants completely throughout the wood. This waterbased system imparts a minimal amount of added moisture into the wood during the process, so there is no need to dry after treatment. A short activation period is utilized to achieve full penetration. For larger wood profiles, such as decking members and railroad crossties, the use of pressure/vacuum impregnation accelerates the penetration. The Buffered Amine Oxide Treatment System is in commercial use in the United States, New Zealand and Australia; where numerous programs have been developed for residential and industrial wood products. To date, over 2,000,000 m3 (847,552,001 board feet) of wood has been treated utilizing the Buffered Amine Oxide Treatment System. The most modern Buffered Amine Oxide Treatment System has been designed to fully and completely impart azoles/insecticide wood preservatives into Douglas Fir and Eucalypt wood profiles.
R W Clawson Jr


A Treatability Study of Western Wood Species with Water Based Azoles and Insecticides Using Buffered Amine Oxides
2016 - IRG/WP 16-40766
The use of Western U.S. Wood Species remains small in today’s global wood product market when compared to the use of other commercially available softwoods. One reason that other fiber sources, those that may be less naturally durable or exhibit slightly inferior mechanical properties, are utilized is ease of treatment. In an attempt to ensure adequate penetration in commercially important and difficult-to-treat Western Wood Species such as Douglas fir, Hem fir, and 100% Heart Redwood, the use of deep incisions is standard practice. The development of solvent-free, Water Based Buffered Amine Oxide Treatment Systems (known commercially as TRU-CORE® Technology) for use in wood preservation has allowed significant modernization of the application and preservation process for these species. Important to the future growth of Western Wood Species may be the elimination of incising. When the Buffered Amine Oxide Treatment System technology is utilized it has been demonstrated that non-incised difficult-to-treat species are fully penetrated in the sapwood and heartwood. The buffered amine oxides allow for a chemically based infusion process that is capable of delivering key wood protectants completely throughout the wood. This water based system imparts a minimal amount of added moisture into the wood during the process, so there is no need to dry after treatment. To date, there are over 50 commercially successful Buffered Amine Oxide Treatment Systems. In 2015, over 4,000,000 m3 (1.695 billion board feet) of wood was treated with the Buffered Amine Oxide System.
R W Clawson Jr, C N Cheeks, K A Cutler


Amine Oxides for Use in Wood Protection: I. A Formulation Adjuvant and Performance Enhancer for Wood
2007 - IRG/WP 07-30425
Amine oxides have great potential for use in the area of wood protection. This paper highlights the advantages of using amine oxides as a formulation adjuvant and performance enhancer for different azoles. It was found that azoles are readily soluble in aqueous amine oxide solutions and form soluble concentrates. These azole/amine oxide concentrates have excellent storage stability and can be diluted with water to obtain clear solutions for end use applications. The mold resistance of the azole treated wood was considerably improved with the addition of amine oxides. Two-year above ground tests revealed that the combination of amine oxides and azoles significantly improved efficacy against molds compared to amine oxides or azoles alone. The lap joint test showed no decay or only slight degradation at all retention levels after five years, while the untreated controls had severe decay with numerous failures.
Xiao Jiang, L Walker


Amine Oxides for Use in Wood Protection: II: Water Repellent Agents for Wood
2007 - IRG/WP 07-30426
Wood treated with cetyl and stearyl amine oxides was evaluated to determine its long term water repellency. Comparative water uptake data, generated during two years of outdoor exposure, illustrated that Lonza’s products, Barlox® 18S (N-octadecyl-N, N-dimethylamine oxide) and Barlox® 16S (N-hexadecyl-N, N-dimethylamine oxide), were effective water repellent agents, imparting lasting water resistance in treated wood. A conventional wax based water repellent system showed superior initial results for water resistance; however, the water repellent ability of the wax based system started to degrade after four months of weathering and was significantly deteriorated after two years of outside exposure.
Xiao Jiang, L Walker


Amine Oxides for Use in Wood Protection: III. Penetration Aids for Wood
2008 - IRG/WP 08-30461
This paper highlights the advantages of using amine oxides as penetration aids for quaternary ammonium compounds (quats) and azoles in the area of wood protection. It was found that the use of amine oxide effectively enhanced the penetration and distribution of quats and azoles. For both southern yellow pine (SYP) and Douglas fir wood samples, the addition of cocodimethylamine oxide (Barlox® 12) in didecyldimethylammonium bicarbonate/carbonate (Carboquat® 250T) significantly improved the penetration of Carboquat® 250T. SYP and Douglas fir wood blocks treated with Barlox® 12 and Carboquat® 250T exhibited 60% and 57% increase respectively in quat retention in the center cross section wafer compared to samples treated with Carboquat® 250T alone. The blend of Barlox® 12 and propiconazole treatment showed roughly a 37% and 33% improvement in azole retention in the middle cross section piece of SYP and Douglas fir wood blocks. Using amine oxide, the retention of quat and azole in the inner zone was comparable to the retention of quat and azole in the outer zone in the absence of amine oxide. The color indicator spray test and chemical analysis illustrated an even distribution of the active preservatives of quat and azole in wood with the aid of amine oxide. It was further confirmed by chemical analysis that amine oxide can carry quats and azoles into wood to the same depth as amine oxide travels into the wood. Therefore, it is suggested that amine oxide measurement can be used as a surrogate agent to determine the presence of azoles in the treated wood.
Xiao Jiang


Borate Redistribution in Glulam in an Above Ground Field Test
2014 - IRG/WP 14-30652
Researchers have refocused on the use of boratesin the wood protection industry in the last two decades due to their broad spectrum effectiveness against fungi and insects, and favourable environmental characteristics. This study was designed to determine borate distribution in a limited number of samples from a large field test of composites protected by a combination of coating and borate treatment by two processes.The intended application of these products was exterior components of buildings with considerable protection by design, but the test method was designed to be a much more severe exposure. A variety of structural composites had been machined into ɣ-joint test samples, then borate-treated by two methods: a surface-applied penetrating process, and a dip treatment with borate/glycol plus insertion of copper/borate rods.After application of the coating the test samples had been installed in a long-term above-ground outdoor weathering trial at FPInnovations’ Maple Ridge, British Columbia test site. After seven years of exposure, selected glulam beams of black spruce, white spruce, and Douglas-fir samples were destructively sampled and analyzed for borate retention and penetration, with results compared to unexposed material.Results showed that borateshad migrated from the surface of exposed samples to inside the wood, as deep as 50 mm, and in many samples were present in concentrations that would be sufficient to prevent fungal decay.
P I Morris, A Temiz, J Ingram


Reducing Extractives Stain in Western Red Cedar Sidewall Shingles
2014 - IRG/WP 14-30654
One of the aesthetic challenges that western red cedar shingles face is extractives redistribution stain, particularly in unpainted sidewall applications. Dip and pressure treatments with a mixture of quaternary ammonium compounds and alkyl amine oxides were investigated for their ability to prevent this stain. After nine months of exposure in Vancouver, extractives stain was present on nearly all untreated shingles, but was greatly reduced in incidence and intensity on both the dip- and pressure-treated shingles. Longer-term potential benefits (increased durability) and risks (accelerated weathering) of these treatments should be investigated.
R Stirling


Above-ground performance of a buffered amine oxide treatment system against Mastotermes darwiniensis
2016 - IRG/WP 16-10855
Above-ground H2 field tests against Mastotermes darwiniensis were conducted in far north Queensland to assess the efficacy of buffered amine oxide treatments in the softwoods Pinus sylvestris and P. radiata, and the hardwoods Eucalyptus regnans and E. diversicolor. Untreated hardwoods and slash pine bait wood (P. elliottii) were severely attacked or destroyed, while untreated P. sylvestris was moderately to heavily attacked and untreated P. radiata only light-moderately attacked probably due to its high heartwood content. In softwoods, the H2 (permethrin) and H3 (Cu Quat) buffered amine oxide treatments were more effective than comparative H2F and H3 LOSP treatments. Nevertheless, as test blocks were cut after treatment from longer lengths, all treatments had some replicates with holes often penetrating deeply from the ends, indicating treatment breach against this most voracious of termite species. Unlike the softwood trial, hardwood test blocks were treated in final form and any damage that occurred was from the sides. All H2 buffered amine oxide treated hardwood blocks were sound, while some damage occurred in other treatments.
L J Cookson, R W Clawson Jr


Wood Protection Through Diffusion: Dimensional Stabilisation with Amine Oxides
2019 - IRG/WP 19-30747
Wood is a phenomenal construction material. In addition to its great physical properties and its beautiful appearance, it possesses many environmental-friendly virtues like the sequestration of carbon dioxide. It is however subject to dimension changes when submitted to fluctuating moistures levels, which can lead to warps, cracks and the peeling of paints. Many water repellents can slow down the absorption of liquid water, but very few wood treatments have an actual effect on the absorption of air moisture (Wang & Piao, 2010). These treatments usually impregnate wood under high pressures and/or vacuum and increase significantly the density of the treated wood (Reinprecht, 2016). In this project, wood was impregnated through diffusion with amine oxides and organic fungicides. The treated wood evaluated for its dimensional stability and its uptake of chemicals.
S Pepin, P Blanchet, V Landry


Testing of alkylammonium compounds
1981 - IRG/WP 2152
Following laboratory soil block tests which showed that Bardac 20 possessed a fungicidal threshold similar to that of chromated copper arsenate, treated ponderosa pine sapwood stakes were installed in a field test site near Vancouver, Canada. Two years after installation all the stakes show signs of fungal degradation. Seven stakes have been removed from the test due to total loss of strength after only two years, and many others are near failure due to extensive decay. It may be concluded from this study, that under the conditions of the test, Bardac 20 has failed to prevent wood-destroying fungi from decaying the stakes. Further investigation of treated "check" stakes and failed field tested stakes has revealed an uneven distribution of the chemical in some stakes treated to low retentions.
J N R Ruddick


Effectiveness and synergistic effects between copper and polymer betaine
1996 - IRG/WP 96-30097
Different formulations of "Copper Amine" and Polymer Betaine were studied. During laboratory tests a synergism between both active ingredients against soft rot and dry rot has been found. The efficacy against soft rot according to the "BAM method" and the European Standard ENV 807 depends only on the amount of copper. Long term tests in a fungus cellar for determining the relative protective effectiveness in ground contact show similar results as CCA-treated wood.
H Härtner, V Barth


Oxalate production and calcium oxalate accumulation by Gloeophyllum trabeum in buffered cultures
1994 - IRG/WP 94-10075
Most basidiomycetous fungi produce oxalic acid as a result of their metabolic activities and nutrient procurement. There is currently a renewed interest in the role that oxalic acid may play in the decomposition of wood by basidiomycete fungi. It has been observed that although most wood degrading fungi have the capacity to produce oxalic acid, not all of these organisms express this capacity equally in the wood environment. In addition, not all of the fungi which produce oxalic acid will accumulate this metabolite. Very often the production of oxalic acid is coincident with the precipitation of oxalate salts such as calcium oxalate. At this time it is unclear as to what controls the differential production and accumulation of oxalate by wood degrading fungi. An investigative series of experiments was established using the brown rot fungus Gloeophyllum trabeum to examine the conditions which favor oxalate production and accumulation as manifested through the production of metastable calcium oxalate dihydrate crystals. Batch cultures which were buffered by base cation exchange sites of mineral amendments stimulated the production of calcium oxalate crystals. The results of these buffering experiments indicate that at pH values below approximately 6.0 there is a diminution of oxalate accumulation, and that a pH environment of approximately 3.0 is consistently attained in weakly buffered cultures inoculated with this fungus. These pH values correspond to the pH optima for oxaloacetase (EC 3.7.1.1) and oxalate decarboxylase (EC 4.1.1.2) respectively, and thereby suggest a mechanism for both pH control and oxalate production and accumulation.
J H Connolly, J Jellison


Contribution of wood components on the absorption of copper amine
2000 - IRG/WP 00-30216
The contribution of wood components on the absorption of copper amine was investigated. Holocellulose, lignin and xylan absorbed significant amount of copper. The amount of copper absorbed by cellulose was almost negligible. The removal of extractive also decreased the amount of copper absorption. This study clearly indicates the importance of lignin, hemicellulose in the absorption of copper amine in wood.
D P Kamdem, Jun Zhang


Evaluation of the corrosivity of the treated wood - Laboratory vs field test methodologies
2000 - IRG/WP 00-20211
The corrosivity of treated wood to fasteners has been evaluated using laboratory test procedures, including AWPA Standard E12-94. The standard method was modified in order to allow detailed study of commercial metal fasteners in terms of sample types, installation configuration and exposure conditions. Parallel field tests were also performed. The experimental results generated from these tests suggest that the laboratory test methods accelerate metal corrosion relative to the field performance conditions for only certain preservative treatments. The influence of performance properties of water repellent treated wood on the corrosivity testing methods is also discussed.
L Jin, A F Preston


Preservative-efficacy of boric acid-triethanol amine solution against wood-decay fungi
1994 - IRG/WP 94-30050
Laboratory preservative-efficacy tests were conducted using boric acid-triethanol amine (BTEA) solution in accordance with the JIS A 9201 (1991) test method excluding the standard weathering process. Sapwood specimens of Picea jezoensis or Fagus crenata to achieve nominal retentions of 0.40-41.2 kg/m³ of boric acid were exposed to Tyromyces palustris, Coriolus versicolor, Serpula lacrymans or Chaetomium globosum, respectively. Mean percentage mass loss data showed the following threshold values: 1.65-2.13 kg/m³ for Tyromyces palustris; 1.60-1.94 kg/m³ for Coriolus versicolor; 0.43-0.83 kg/m³ for Serpula lacrymans; 8.0-23.8 kg/m³ for Chaetomium globosum. The values against Coriolus versicolor and Serpula lacrymans were lower than those of Tim-Bor® as boric acid retention.
S Doi, M Mori, Y Mineki


Adsorption of ACQ and CuMEA Wood Preservatives in Red pine
2005 - IRG/WP 05-30374
The rates of stabilization or fixation of ACQ subcomponents (CuO, DDAC and MEA) in red pine (Pinus resinosa) were compared for different solution concentrations (0.75%, 1.5%, 2.25% and 3% ACQ-D) and post treatment conditioning temperatures. Preservative solutions were impregnated into red pine sapwood by a full-cell treatment. Copper and MEA adsorptions from copper monoethanolamine solutions without DDAC were also evaluated for comparison. After the treatments, samples were conditioned without drying either at 22° C for seven weeks or at 50° C for one week. At different times after treatment, expressate from the specimen blocks was analyzed for copper, DDAC and MEA. Copper and MEA adsorption by the wood cell walls followed similar trends. The equilibrium copper adsorption ranged from 44% at high ACQ retentions to about 95% for the lowest retention while the values in the CuMEA system were slightly higher for the higher retentions, ranging from about 54% to 93%. This suggests that DDAC may compete with CuMEA for reaction sites at high ACQ concentrations. Adsorption of DDAC into the wood cell wall matrix was rapid; at all solution concentrations, more than 80% of DDAC was adsorbed by red pine sapwood within minutes after treatment.
C Tascioglu, P A Cooper, Y T Ung


Evaluating the potential of amine chemicals for use as wood protecting agents. Part 1: Investigation of cation components of quaternary ammonium compounds
1994 - IRG/WP 94-30049
Quaternary ammonium compounds (quats) have shown a great potential as more environmentally acceptable wood preservatives. In order to identify chemicals possessing the wood protecting potential, an evaluation was carried out of a range of commercially available 'quats', using a modified soil block test. Ponderosa pine sapwood blocks were treated with selected 'quat', leached with water and sterilized with gamma radiation. The blocks then were exposed to Postia placenta, Gloeophyllum trabeum and Trametes versicolor in soil jars. After incubation at 25°C for twelve weeks, weight losses of the blocks after the test were calculated and the fungal toxic threshold determined. The four 'quats' examined were very effective in preventing attack of ponderosa pine sapwood blocks by the three fungi.
Hang Tang, J N R Ruddick


Tests with ammoniacal copper and alkyl ammonium compounds as wood preservatives
1984 - IRG/WP 3299
Formulations based on copper and alkyl ammonium compounds in ammonia solution have been tested in a fungus cellar on Pinus radiata and Fagus sylvatica. This type of products gives promising results as wood preservatives, especially on hardwood and are safe to destroy by e.g. combustion. The best results were achieved with a dialkyl ammonium compound, Cu/octyldecyl dimethyl ammonium chloride (NH3). The optimal weight ratio of Cu/AAC is for Pinus radiata = 0.2-0.4 and Fagus sylvatica = 1.0 based on cost-effectiveness. Fixation and leaching of coppertetrammine are discussed in detail. The leaching of active components from the Cu/AAC/NH3-systems is very low.
C-E Sundman


Influence of carboxylic acids on LEACHING of copper amine based preservatives
2005 - IRG/WP 05-30365
The importance of chromium free preservatives is increasing. Leaching of copper from wood preserved with such solutions is still higher compared to leaching from wood impregnated with copper chromium ones. In order to decrease leaching, different carboxylic acids (octanoic, 2-etilheksanoic, decanoic) were added to copper/amine/boron aqueous solutions. Experiment of leaching of copper from Norway spruce (Picea abies) was performed according to the modified standard procedure (EN 1250). Results presented in this paper showed, that carboxylic acids significantly improve copper fixation. The best one was determined at specimens impregnated with the preservative solutions consisting of copper, ethanolamine, boric acid and octanoic acid.
M Humar, P Kalan, F Pohleven


Determination of the amine to copper ratio remaining in wood after leaching
2002 - IRG/WP 02-30285
The effectiveness of the protection and the environmental impact of the treated wood are two of the most important aspects that need to be understood for all preservatives. Both are particularly influenced by the loss of biocidal components from treated wood. For amine copper preservatives, copper fixation determines the leaching resistance of the copper and amine compounds formed in wood. Previous research has suggested that the degree of copper fixation may be influenced by the amine-copper formulation (including the type of amine), the copper concentration and the ratio of the amine to copper in the treating solution. However, the relationship between amine and copper concentration and the fixation efficiency is not fully understood. The purpose of this study is to determine the influence of a) the type of amine, b) the concentration of copper, and c) the amine to copper mole ratio, on the fixation chemistry of amine-copper preservatives.
N Lucas, J N R Ruddick


Weathering of copper-amine treated wood
2000 - IRG/WP 00-40155
Copper ethanolamine (Cu-EA) treated southern pine (SP) were artificially weathered with a QUV Weathering Tester. The weathering regime was composed of a continuous UV-light irradiation for 2 hours followed by a water spray for 18 minutes for a total time of 1200 hours. The changes on the surface of the weathered samples were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, color and contact angle measurements. FTIR indicates that Cu-EA treatment can retard the surface degradation during weathering. The reduction of the peak intensity at 1510 cm-1, characteristic of the wood lignin was less pronounced for Cu-Ea treated wood than for untreated or ethanolamine treated wood. This reduction in 1510 cm-1 intensity decreases with the increase of copper EA retention in treated wood. The color change expressed by the value of DE indicated that untreated and Cu-EA treated wood change color rapidly during the first 200 hours irradiation and the color change remained relatively constant thereafter. The values of DE for untreated and ethanolamine treated sample were higher than the values of Cu-Ea treated. Changes in the lightness of wood samples were also observed with the duration of irradiation. The lightness of untreated and Cu-MEA treated samples decreased during the first 100-hour weathering. These samples regained their lightness after 100 hours irradiation. For samples treated with copper concentration above 0.25%, the change in lightness was rather small. The contact angle measurement indicates that the wettability of wood surface increases with the duration of QUV exposure. Untreated and MEA treated wood samples changed contact angles rapidly, and The contact angle of untreated and ethanol amine treated samples dropped from about 75"5 degree to zero after 600 hours artificial weathering. Treatment with Cu-MEA can slow the decreasing in contact angle. After 1200 hours, the contact angle of Cu-EA treated wood dropped from 100 to a minimum between 25 and 60 degree. As the copper concentration increases, the rate of changing contact angle decreases. This study suggests that a copper amine treatment increases the hydrophobic and the resitance to photodegradation.
J Zhang, D P Kamdem


Amine copper reaction with wood components: acidity versus copper adsorption
1997 - IRG/WP 97-30161
The bonding sites for copper in wood from CCA, as well as ammoniacal/amine based systems, has long been a topic of investigation. Both phenolic and carboxylic functional groups have been discussed as potential bonding sites for copper. However, no consensus on the adsorption mechanism has been realized. Thus, the selective adsorption of copper in southern yellow pine from ethanolamine-copper solutions and its correlation to wood acidity is currently being investigated. The wood acidity has been determined by acid/base titration, and is due to more than one type of acidic group. The acid(s) can be removed by thermal treatment or extraction techniques, and, interestingly, the selective adsorption of copper was observed to track the presence of particular acid functionalities. The preferential adsorption of copper and the mechanisms behind such will be discussed.
S M Thomason, E A Pasek


Interaction of copper-amine complexes with wood: Influence of copper source, amine ligands and amine to copper molar ratio on copper retention and leaching
1999 - IRG/WP 99-30203
The absorption and leachability of copper in copper amine (Cu-EA) treated wood are influenced by the formulation and the composition of copper amine treating solutions. The sources of copper used, Cu(OH)2, CuCO3, CuSO4 and Cu(NO3)2, in the copper amine complex formulation affect the leachability of copper. Data show that copper amine from CuSO4 and Cu(NO3)2 treated wood has less copper loss during laboratory water leaching than those from Cu(OH)2 and CuCO3 treated wood. Increasing amine to copper molar ratio increases the copper retention by wood, but reduces the leaching resistance of copper. The nature of amine ligands, such as monoethanolamine (primary amine), 2-methylamino-ethanol (secondary amine) and N, N-dimethyl-ethanolamine (tertiary amine), has some effect on copper retention and copper leaching. As the molecular weight of amine ligands increases, copper loss during leaching decreases.
Jun Zhang, D P Kamdem


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