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Fire resistance of wood treated with potassium carbonate and silanes
2014 - IRG/WP 14-30657
This paper reports on the effect that organosilicon compounds and potassium carbonate and urea (PCU) have on wood flammability. The study focus on reducing wood flammability by promoting char formation through manipulation of the condensed phase decomposition chemistry. Potassium carbonate is known as an effective fire retardant, however it is easily leached out from wood and increases its hygroscopicity. The aim of the research was to assess the ability of selected organosilicon compounds to reduce potassium carbonate leachability from the treated wood. The study was performed through the mini fire tube (MFT) method, where fireproofing properties of the treated wood were evaluated. Pine sapwood treated with PCU at the retention of ca. 160kg/m3 showed 6% of wood mass loss as a result of combustion in MFT. The fireproofness effect has been reduced due to the ageing procedure and displayed 60% of wood mass loss. It has been shown that some selected silanes or their blends with siloxanes, superficialy applied on treated wood, allowed to retain PCU in wood and maintain its fireproofness. Wood mass loss resulting from sample’s combustion was significantly reduced (ML<10%). AEAPTMOS, VTMOS and a mixture of alkylalkoxysilanes turned out to be most effective agents limiting potassium carbonate leachability and maintaining wood fireproofness.
B Mazela, M Broda, W Perdoch


Physical and biological properties of albizzia waferboards modified with cross-linking agents
1995 - IRG/WP 95-40043
Chemically-modified low-density waferboards with cross-linking agents were produced using a fast-growing species of hardwood albizzia (Paraserienthes falcata Becker) as a raw materials and isocyanate resin as a glue adhesive. For the chemical modification, the vapor-phase formalization of the boards and the pad-dry-cure treatment of wafers with cross-linking agents were employed. The vapor-phase formalization was conducted for 5, 10 and 24 hours using tetraoxane as a source of formaldehyde, and the pad-dry-cure treatments with glutaraldehyde and ethyleneurea compound (DMDHEU) were made after impregnation of their 5 and 10% aqueous solutions of each chemical. Sulfur dioxide was used as a catalyst in both treatments. About 70% of antiswelling efficiency (ASE) was gained in all treated boards irrespective of reaction time or solution concentration. All treated boards were very stable to water soaking even in the 2-hour boiling on thickness swelling as well as linear expansion. Laboratory tests with brown-rot and white-rot fungi revealed that decay was completely suppressed in formaldehyde-treated boards, and small losses in weight were counted in other treated boards. All treated boards were also effective in resisting to the attack by the destructive termite Coptotermes formosanus.
S Yusuf, Y Imamura, M Takahashi, K Minato


Effects in vivo of various tensides (surface-active agents) on Reticulitermes santonensis De Feyteaud
2001 - IRG/WP 01-10417
The results of studies of surface active agents (tensides, surfactants) on the feeding behavior and mortality of Reticulitermes santonensis De Feyteaud are described. The effects of these agents on the nature and relative populations of eight gut-inhabiting symbionts are also examined. Among the various tensides tested, bee&apos;s poison was the most effective in causing rapid termite death. All surfactants were detrimental to the flagellated symbionts. The differences in magnitude and rapidity of the symbionticidal effects are described and discussed.
W Unger


Involvement of hydrogen peroxide in wood decay by brown-rot and white-rot fungi
1985 - IRG/WP 1256
To gain further understanding of the role of H2O2 in wood degradation by brown- and white-rot fungi, we studied the following: (a) extracellular H2O2 production, (b) effect of various hydroxyl radical (·OH) and singlet O2 (1O2) quenching agents on wood and cellulose degradation, (c) intracellular H2O2 production and catalase activity, and (d) cytochemical localization of H2O2 with diaminobenzidine (DAB) during wood degradation. Extracellular H2O2 detection varied with the growth media and chromogen. The chromogen 2,2&apos;-azino-di-(3-ethyl benzthiazoline-6-sulphonic acid) (ABTS) was more sensitive than o-dianisidine. Extracellular H2O2 was not detected in half of the brown-rot fungi. One white-rot fungus did not produce detectable amounts of H2O2. ·OH and 1O2 quenching agents generally did not inhibit decay of wood or decomposition of cellulose by either brown- or white-rot fungi. DAB did not detect the presence of H2O2 within or outside cells of the brown-rot fungus, Poria placenta. Nor was H2O2 -generating activity detected in sonicated extracts of this fungus. With the white-rot fungus, Coriolus versicolor, H2O2 occurred predominantly in the periplasmic space, but also in the cytoplasm and hyphal sheath. Sonicates of Coriolus versicolor contained H2O2 -generating activity. These observations provide further support for H2O2 involvement in degradation of wood by white-rot fungi, but raise doubts concerning its participation in wood degradation by brown-rot fungi.
T L Highley, L L Murmanis


Biological agents of timber degradation in Portugal. Marine borers
1991 - IRG/WP 4171
A brief report of the studies carried out in Portugal on marine borers is presented. The marine borers found in the portuguese coast are refered as well as the wood species where those organisms were identified. Emphasis is given to a study carried out from 1960 to 1975 at the Tagus estuary in Lisbon with the purpose, among others, of establishing the natural durability of different timbers.
J S Machado, L Nunes


Co-operative research at the Naval Research Laboratory on wood extractives and related compounds as antiborer agents
1977 - IRG/WP 429
J D Bultman, K K Parrish


Feasibility of using biological control agents to arrest and prevent colonization of Douglas fir and southern pine by decay fungi
1988 - IRG/WP 1345
The use of microfungi to control basidiomycetous decay has been evaluated in Europe for many years, where it has produced mixed results against Lentinus lepideus Fries, the fungus presumed to be the major cause of decay in Scots Pine poles. In the United States, remedial decay control has been largely chemical, with little use of alternative decay control strategies. Increasing restrictions on chemical usage have stimulated renewed interest in biological decay control. In our tests, a European biological control, BinabÒ,was evaluated for its ability to prevent or arrest attack of southern pine sapwood or Douglas fir heartwood by 5 Basidiomycetes commonly isolated from poles in service. Lentinus lepideus was included as a comparison. In general, BinabÒ performed well against Lentinus lepideus and the other brown rotters, but was unable to completely eliminate most of the test fungi. In addition, the biological had little effect on white rot fungi, which are an important component of the microflora in decaying poles. The results suggest that biologicals will not be suitable for remedial decay control without supplemental treatments that favor growth and activity of the biocontrol agent.
J J Morrell, C M Sexton


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 &apos;quats&apos;, using a modified soil block test. Ponderosa pine sapwood blocks were treated with selected &apos;quat&apos;, 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 &apos;quats&apos; examined were very effective in preventing attack of ponderosa pine sapwood blocks by the three fungi.
Hang Tang, J N R Ruddick


Preliminary evaluations of a small wafer assay for screening potential biological control agents
1989 - IRG/WP 2332
Screening potential biological agents for controlling wood decay fungi poses a dilemma. The ideal test would eliminate as many variables as possible. Most tests utilize pure cultures of the test organism on an artificial media which in no way resembles wood. The use of sawdust improves this approach, but the sawdust increases fungal access to the lignocellulose matrix, potentially inflating the importance of fungi which might not compete in the normal wood system. This report describes a simple wafer sandwich assay in which small test wafers colonized by the potential biocontrol agent and a Basidiomycete are placed above and below a sterile test wafer on moist soil in a glass petri dish. Weight loss of the middle wafer is used as a measure of biocontrol potential. Preliminary trials indicate that several previously identified biocontrol agents performed well in this test, inhibiting wood weight losses by both white and brown rot fungi. Because the wood structure is not disturbed, this method could also be used to screen wood treatments which might enhance colonization by the biological control agent.
C M Freitag, J J Morrell


Influence of hydrophobic agents on the leachability of boron
1995 - IRG/WP 95-30064
Besides its low mammalian toxicity and a broad range of activity towards both fungi and insects, boron shows a high diffusibility, encouraging it to treat wood species of low permeability. However, its difussibility is at the same time responsible for a high risk of leaching, known since long. Nevertheless quantitative data about this process are only rarely available. Therefore, the leaching of boron under different conditions and possible means of hydrophobising boron treated wood in order to reduce leaching were investigated by laboratory and field tests. For this purpose paraffin and a primer have been applied to protect the inner surface and alkyd-resin and a varnish as surface coat. The results demonstrate that boron diffuses even at moisture contents below 20%. Thus leaching can not be affected by hydrophobic agents placed on the inner surface of wood because diffusion still takes place within the cell-wall. Surface coatings have some protective effect but only during a distinct periode which is depending on the thickness of the coat. With time leaching increases with increasing moisture content underneath this coat. The best way to prevent leaching is the logistical protection by storing and using boron-treated wood exclusively under cover. Only for a short periode, for example during construction, a surface protection with waxes or resins will be effective.
A Peylo, H Willeitner


Preservative treatment of rubber wood (Hevea brasiliensis) to increase its service life
2005 - IRG/WP 05-40320
Rubber wood (Hevea brasiliensis) possess excellent properties for interior designing, wood working and furniture making. But it is very much susceptible to sap stain and mould fungi which decreases the service life. For profitable uses , it is necessary to increase the service life of rubber wood. To protect the rubber wood from wood degrading agents, the sawn timber were treated with Borax – boric acid solution and Copper-chrome -boron solution by soaking process and Lowry empty cell pressure process following moderate treatment schedule. It was found that rubber wood can be treated satisfactorily by both the processes with acceptable penetration and retention.
K Akhter


Stake test with ammoniacal copper in combination with different agents started in 1962
1997 - IRG/WP 97-30130
In 1962 a stake test was started with ammoniacal copper in combination with chromium, arsenic, pentachlorophenol, boron, salicylic acid, benzoic acid, sorbic acid, pyridine and tannin. Different concentrations of the copper component were used as well as the added agents. For each concentration and test site, ten stakes of Pinus sylvestris L. sapwood were treated. The stakes were set out at two test fields in Sweden, Simlångsdalen and Bogesund and also in a greenhouse. Today all stakes except five at Bogesund have been rejected. The prevailing type of decay in Bogesund is soft rot and in Simlångsdalen brown rot and soft rot. Ammoniacal copper alone at a copper retention of 1.9 kg/m3 gave an average service life of 23 years in Bogesund and 14 years in Simlångsdalen. When the copper retention was doubled to 3.8 kg/m3 the service lives were prolonged by 2-3 years in Bogesund and 8-9 years in Simlångsdalen. Most of the agents added to copper prolonged the service lives substantially in Simlångsdalen but only marginally, or not at all in Bogesund. The added agents which gave the longest service lives at both test fields were chromium plus arsenic and pentachlorophenol.
B Häger, Ö Bergman


Effects of chemical pretreatment of Douglas-fir heartwood on efficacy of potential bioprotection agents
1990 - IRG/WP 1440
Biological protection against wood decay fungi represents an environmentally attractive alternative to the use of chemicals; however, the process of identifying suitable candidates and the conditions that ensure successful protection pose major challenges. One critical aspect of this problem is to identify organisms that can rapidly and uniformly colonize the wood. Wood contains low levels of nutrients required for the growth of many potential biocontrol agents, particularly in the heartwood. One approach to enhancing colonization by the bioprotectant is to treat the wood with low levels of chemicals that inhibit other microbes or selectively stimulate the bioprotectant. Ideally, these chemicals would be capable of diffusing in vapor or liquid phase through wood that is impermeable to the movement of conventional preservative systems. The feasibility of this approach was evaluated in a small wood wafer test using fluoride and boron, two elements that have been shown to inhibit members of the Basidiomycotina but produce minimal effects on microfungi.
B Dawson-Andoh, J J Morrell


Laboratory trials of biological control agents against subterranean termites
1991 - IRG/WP 1475
To screen for potential termite control by microorganisms, 17 mold fungi included 3 pathogenic fungi and 7 basidiomycetes, were used to challenge the test termite species, Coptotermes formosanus and Reticulitermes speratus. Test fungi were allowed grow and completely in Petri dishes. To screen for potential termite control by microorganisms, 17 mold fungi included 3 pathogenic fungi and 7 basidiomycetes, were used to challenge the test termite species, Coptotermes formosanus and Reticulitermes speratus. Test fungi were allowed grow and completely in Petri dishes (Æ = 9 cm, h = 15 mm) and to avoid contaminant fungi from growing on the medium, the sterilized agar without nutrients were used for controls instead of the agar medium. Termites were introduced to each dish on sterilized filter paper supported by the agar medium. Paecilomycetes fumosoroseus, Metarhizium anisopliae, Beauveria bassiana and Aspergillus niger, exhibited the best control of the termites. In comparison with the control, blue stain fungi like Cladosporium cladosporioides, showed no effect on the termites. Fungal pathogenicity to termites was examined in exposure tests using fungal attacked wood specimens of Pinus densiflora and Betula platypylla var. japonica (2 x 2 x 1 cm³) in Petri dishs. Paecilomycetes fumosoroseus, Metarhizium anisopliae and Beauveria bassiana infected wood blocks were attacked by termites within 7 days in this test. All fungi were isolated from dead termite bodies at the termination of the test.
K Suzuki


Methods to determine the efficacy of three water repellent additives in waterborne preservatives
1997 - IRG/WP 97-30142
The paper describes the methods used to determine the efficacy of three different water repellent additives in waterborne preservatives. The wooden samples used are pine (Pinus sylvestris) and spruce (Picea abies) that are treated with 9 different waterborne preservatives in retention for hazard class 3 (above ground commodities). There are two sample sizes exposed, cladding boards (19 x 148 mm) with a sawn surface exposed 60 ° facing south, and decking boards (21 x 95 mm2) with a planed surface exposed horizontally. The boards&apos; dimensions have been measured and water repellent properties have been checked three times with water droplets during exposure in 2.5 years. During the winter 1996/1997 and spring 1997 we have logged the temperature and moisture content in eight of the boards for one of the additives; also with and without preservative (CCA). We log every half hour. The RF is also logged. This paper will in addition to describing the methods also give the results after 2.5 years, while a subsequent paper will give the results for the efficacy of the different additives.
F G Evans, B Nossen, K M Jenssen, L R Wilhelmsen, G Fuglum


Biological control of sapwood-inhabiting fungi by living bacterial cells of Streptomyces rimosus as a bioprotectant
1992 - IRG/WP 92-1564
The objective of this study is to evaluate the efficacy of antifungal activity of living bacterial cells for the protection of wood against sapwood-inhabiting fungi. The following sapwood-inhabiting fungi were selected: sapstain --Ceratocystis coerulescens, Ceratocystis minor, Ceratocystis pilifera, and Aureobasidum pullulans; mold fungi --Aspergillus niger, Penicillium spp, and Trichoderma spp. Living bacteria cells as a bioprotectant were studied in the laboratory using Southern pine and sweetgum block tests, and in field exposure trials with green pine log sections. Living bacterial cells inhibited spore germination, and therefore discoloration in laboratory wood block tests and in pine log sections exposed in field tests.
S C Croan, T L Highley


Moisture correction for ultrasonic MOE measurements above fibre saturation point in Scots pine sapwood
2006 - IRG/WP 06-20333
There is a high correlation between methods for dynamic modulus of elasticity (MOEdyn) and static modulus of elasticity (MOEstat). MOEdyn methods have been found sensitive to detect early stages of decay and may be seen as an option for non-destructive wood durability testing. As the MOEstat measurements do not change after reaching the fibre saturation point, the uncorrected MOEdyn data from ultrasonic pulse excitation method provides increasing values after fibre saturation. This is due to the effect of free water in the cell lumen on ultrasonic waves. The aim of this study was to make a moisture calibration for the MOEdyn ultrasonic pulse excitation method using Scots pine (Pinus sylvestris L.) sapwood samples. MOE was measured at five different moisture levels. Three different MOE test methods were used: MOEdyn using ultrasound and vibration excitation and the traditional MOEstat. Sound Scots pine sapwood samples treated with two copper-containing wood preservatives and two chitosan solutions were evaluated, using untreated sapwood samples as control. In this study a correction value ("k") was calculated based on data from different moisture levels for water saturated samples using four different wood treatments and control. By measuring MOEdyn ultrasonic at wood moisture contents just below fibre saturation point, a minor effect of incipient water accumulation in the wood matrix was detected. Wood treatments influence the "k" value, and a "k" value needs to be calculated for all wood treatments when measuring MOEdyn ultrasound above fibre saturation. All the three MOE test methods in this study are applicable for all wood moisture levels as long as a "k" value is calculated for MOEdyn ultrasound above fibre saturation.
E Larnøy, G Alfredsen, H Militz


Information on a project about the conditions of admissibility of wood-protecting agents in connection with environmental protection in Poland
1974 - IRG/WP 57
Wood-protecting agents are compounds acting toxically on fungi and insects. If handled improperly or carelessly, they may exert an action harmful to health and safety of men. This action is concerning: a) workers employed at the production of wood-protecting agents; b) workers employed at the impregnation, or at the transport and handling of impregnated wood; c) inhabitants of buildings with impregnated wooden elements, or which have been treated against fungi. At the suggestion of the Scientific and Technical Committee for Wood Protection, medical institutes started investigations concerning the influence of wood-protecting agents on human health. A draft has been worked out on the terms of admissibility for the use of these agents. The toxicological specification of a wood-preserving agent has to include the results of the following tests: 1) Determination of hypertoxicity LD50 per os for rats; 2) Determination of toxicity LD50 per coeliacus for rats; 3) Determination of irritant action on the eye mucosa and the skin of the rabbit; 4) Determination of allergenic action on the skin of the guinea pig; 5) Determination of injuring action by histopathological method; 6) Determination of toxicity LD50 by inhalation after 4 hours by rats, given the content of the active substance in mg in 1 litre of air; 7) Determination of the quantity of wood-protecting agents in the air, by means of the cabin method, and their disappearance. The above mentioned determinations are to be carried out according to methods generally accepted for toxicological tests. In certain cases, they have to be adapted to the requirements of the wood-protecting agents tests. As a fundamental criterior for the evaluation of wood-protecting agents in relation to toxical noxiousness we take the toxicity per os of the whole compound, expressed in mg per kg of weight of the living experimental animal (LD50). The other determinations are of complementary character, and in the case of unfavourable results, they cause the agent to be classified at a lower class than having been classified by the fundamental criterion LD50 alone. A classification of 5 degrees has been worked out for the wood-protecting agents, based on the classification of Hodge-Sterner: Degree I: hypertoxic agent (LD50: below 50 mg/kg); Degree II: toxic agent (LD50: 51-150 mg/kg); Degree III: noxious agent (LD50: 151-500 mg/kg); Degree IV: less noxious agent (LD50: 501-5000 mg/kg); Degree V: practical not noxious agent (LD50: above 5000 mg/kg). In accordance with the accepted criteria the toxicity of some wood-protecting agents is as follows: 1) Arsenic compounds - Degree I of toxicity; 2) Sodium fluoride - Degree II of toxicity; 3) Sodium fluoride + chromium salts - Degree II of toxicity; 4) Fluoride/borates + chromium salts - Degree II of toxicity; 5) Zinc fluosilicate - Degree III of toxicity; 6) Bifluorides - Degree III of toxicity; 7) Borax, boric acid - Degree V of toxicity. In Poland the use of wood-protecting agents of the Degree I of toxicity is prohibited. It is planned to withdraw from use progressively wood-protecting agents having higher degrees of toxicity. The present draft and the suggested classification are of preliminary character. They are being submitted for further investigation and discussion to the authorities concerned with health protection and environmental protection.
J Wazny


Some textile auxiliaries as wood protective agents
2007 - IRG/WP 07-30417
This study evaluated some textile auxiliaries applicable for wood protection. Commercial alkoxysilane quarternary ammonium formulation and fluorocarbon based water-oil repellent were tested for their ability to provide hydrophobicity and antifungal effect to solid wood samples. Scots pine (Pinus sylvestris L.) sapwood samples were impregnated with 25, 50 and 100 % concentrations of the above mentioned compounds and cured in an oven at 80 ?C for 24 h. Water absorption rate (WAR), anti-shrink efficiency (ASE) and compression strength parallel to grain of the wood samples were determined. Biological resistance of leached and unleached wood samples against fungal decay was evaluated with a modified soil block test using Postia placenta. Fluorocarbon based water-oil repellent and alkoxysilane quarternary ammonium treated samples demonstrated some improved durability against decay fungi and anti-shrink efficiency compared to the untreated controls. The water uptake of treated wood was significantly reduced, especially after the treatment with alkoxysilane quarternary ammonium. The initial water repellence was well pronounced with the both tested chemicals, but after a longer submersion time (2 weeks), the reduction in water uptake was significantly diminished. No significant decrease of the compression strength parallel to grain of wood samples was monitored. Although the improved durability of wood treated with the tested formulations, the performance is far poorer than that of the commercially available copper-based formulations.
E Dizman, A Temiz, N Terziev, Ü C Yildiz


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


Discovering anti-fungal agents in New Zealand native plants for use in wood protection
2009 - IRG/WP 09-10692
Extracts from Hinau (Elaeocarpus dentatus) leaves were tested in the laboratory for antifungal activity. In addition, the anatomical structure of the leaf was also examined by a combination of light and scanning electron microscopy. Chemical characterisation of the extracts and investigation into potential use of its components for wood protection is underway. A combination of light microscopy (LM) and scanning electron microscopy (SEM) proved most effective for examining the tissue composition, particularly in differentiating the distribution of lignified tissues relative to non-lignified tissues after staining freshly cut leaf sections with phloroglucinol-HCl stain, which specifically stains lignin in cell walls. In-vitro bioassay results showed antifungal activity of Hinau extracts against two brown rot fungi, Oligoporus placenta and Coniophora puteana. NMR spectra of the Hinau extracts indicated mixtures of aromatic substances, showing chemical shifts consistent with ellagitannins and/or gallotannins with minor contributions consistent with flavonoids. The identity of the bioactive component remains unknown.
C Rickard, T Singh, A Singh, R Newman


Enhanced uptake of wood modification agents in “bioincised” wood
2009 - IRG/WP 09-40445
The permeability of refractory wood species e.g. Picea abies and Abies alba is reduced resulting in a radial penetration of chemical solutions of only a few millimetres. Exploitation of these wood species is therefore not possible for many applications. A novel biotechnological method (European patent 05027812.6) based on the pre-treatment of wood with the white-rot fungus Physisporinus vitreus significantly improves the permeability of wood. The present study confirms that `bioincising´ is a promising method for increasing the uptake of a range of wood preservatives and wood modification agents for fire protection, UV protection and dimensional stability or hardness.
F W M R Schwarze, M Schubert


Influence of wood swelling agents on penetration and copper leaching of copper-ethanolamine based wood preservatives
2011 - IRG/WP 11-30556
Copper ethanolamine based preservatives are currently the most important solutions for impregnation of wood in ground contact in Europe. One of the issues related to those and similar water based solutions is insufficient penetration to refractory wood species like Norway spruce. In order to elucidate this issue, commercial copper ethanolamine based solution was supplemented with five different wood swelling agents (ammonia, ethylene glycol, DMSO, formic acid and triethanolamine) of three different concentrations (2.5%, 5% and 10%). Norway spruce wood specimens were impregnated with those solutions, and uptakes of preservative solutions and depth of penetration was determined. Furthermore, copper leaching according to the ENV 1250-2 procedure was determined as well. The results showed that triethanolamine and formic acid were found very effective and improved penetration of copper ethanolamine wood preservative to wood. On the other hand, addition of those two preservatives increased copper leaching from impregnated wood.
M Humar, N Thaler, B Lesar


Optimization of the bi-oleothermal treatment process for wood preservation and fireproofing
2011 - IRG/WP 11-40566
The bi-oleothermal© process (combination of oil and heat treatment) is a well mastered alternative method for wood protection. However, the fire behavior and resistance to decay of bi-oleothermally treated wood are not good enough to ensure performance which meets the service standards for outdoor applications such as cladding or decking expected by the market. The aim of the present research project has been to improve this performance by optimizing the linseed oil formulations used at the impregnation stage. Different formulations combining linseed oil, fungicides, insecticides and/or fire retardants were tested under laboratory conditions in order to assess the resistance of oil-treated wood to molds, decay fungi, longhorn beetles, subterranean termites and fire. The results showed that the investigated biological organisms exhibit different levels of susceptibility to oil based formulations. Additionally, the collected data suggested that some inhibition processes might occur between the oil and the active ingredients, lowering the biocide effect of the final formulation. Subsequently, chemical analyses were performed in order to identify the active ingredients both in the oil formulations used for the second bath and inside the treated wood. The measured concentrations of active ingredients were then compared to the expected target values to determine the possible fate of the biocides in the oil formulations (degradation, migration into wood, interaction between the different components).
F Simon, M Kutnik, M Goyer, M-F Thévenon, C Alfos, M Céron


Removal of nano- and micronized-copper from treated wood by chelating agents
2013 - IRG/WP 13-50294
Micronized and nano-copper (Cu)-based and arsenic and chromium-free systems have received much attention for wood protection in recent years. Because they have different fixation, and micro-distribution properties, such copper systems may be more or less subject to release using known remediation methods than soluble forms of Cu. This study evaluated Cu recovery from wood treated with micronized- or nano-Cu via chemical extraction, and determined optimum release rates of Cu from micronized- and nano-Cu-treated wood compared with the release rates from soluble Cu-based wood preservatives. Chemical remediation in the study included chelating agents EDTA, oxalic acid, bioxalate, and D-gluconic acid at different durations, pH, and concentration levels to remove Cu from treated wood along with distilled water as controls. Cu removal rates increased from around 60% to over 95% when bioxalate was employed in the extraction process for all extraction durations. In extractions of nano CuO-treated wood for 24h, oxalic acid was able to remove 95% of Cu; however, bioxalate was able to remove somewhat less Cu. Bioxalate was, on the other hand, more effective than oxalic acid in removing Cu from ACQ-D, MCQ, MCA, CA-C and Cu-Et-treated wood. D-gluconic acid extractions resulted in the lowest Cu removal rate for nano-CuO. As the pH of D-gluconic acid was reduced from 10 to 2, the percentage Cu removal considerably was improved except for nano CuO. Results suggested that there is no distinctive difference in Cu removal rates among ACQ-D/MCQ, CA-C/MCA and Cu-Et wood preservatives. Nano-CuO was found to be resistant against EDTA extractions. Since it is a weak, noncorrosive, nonvolatile, nontoxic, biodegradable and inexpensive organic acid, D-gluconic acid can be used as an alternative to commercial EDTA and bioxalate in chemical remediation of Cu-treated waste wood.
S N Kartal, E Terzi, B Woodward, C A Clausen, S T Lebow


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