Your search resulted in 133 documents. Displaying 25 entries per page.
Changes in mechanical and chemical properties of wood exposed outdoors
2014 - IRG/WP 14-20550
The aim of this study was to investigate differences in certain mechanical and chemical properties of three different wood species (common beach (Fagus sylvatica), Norway spruce (Picea abies), and copper-ethanolamine (CuE) impregnated Norway spruce (Picea abies)) that were exposed in use class 3 (CEN, 2006) for periods between 4 and 30 months. The results show, that changes in the investigated mechanical and chemical properties coincide, with first signs of fungal degradation after 12 to 18 months of outdoor exposure.
N Thaler, C Brischke, D Žlindra, V Vek, M Humar
Effect of acetylation on decay resistance of wood against brown-rot, white-rot and soft-rot fungi
1989 - IRG/WP 3540
Effect of acetylation on decay resistance of wood was investigated using wood blocks of Cryptomeria japonica, Pinus densiflora, Albizia falcata and Fagus crenata. Blocks were treated with uncatalyzed acetic anhydride for different lengths of time and exposed to Tyromyces palustris, Serpula lacrymans, Coriolus versicolor and unsterilized soil. The action of OH-radical on acetylated wood was also examined using Fenton's reagent. The enhancement of decay resistance by acetylation was revealed clearly for all cases of exposures but varying with fungal and wood species used. For a brown-rot fungus Tyromyces palustris, the weight loss reached almost nil in all woods at 20 WPG (weight percent gain) of acetylation, after the striking decrease from 10 to 15 WPG. For a white-rot fungus Coriolus versicolor, it was counted until 12-15 WPG in the perishable hardwoods used, but not in a softwood Cryptomeria japonica, even at 6 WPG. In cases of another brown-rotter Serpula lacrymans and soil burial, effect of acetylation was intermediate between Tyromyces palustris and Coriolus versicolor. Anti-degradation mechanism by acetylation was discussed, from these weight loss - weight gain relationships, and the IR-and 13C-NMR spectral analyses of fungus-exposed wood.
M Takahashi, Y Imamura, M Tanahashi
Preliminary study of the fungicidal and structural variability in copper naphthenates and naphthenic acids
1996 - IRG/WP 96-30114
Copper naphthenates, an oil-borne wood preservative listed by the American Wood-Preservers' Association (AWPA), is manufactured by complexing copper(II) with naphthenic acids. Prior to AWPA listing as a wood preservative, field experiments showed that copper naphthenates generally had good stability and were active against wood-destroying organisms. Recently, however, there have been reports of some copper naphthenate-treated poles rapidly failing. One possible explanation for the varying effectiveness could be that the structure, and resulting biological activity, of the naphthenic acids used to make copper naphthenate may vary. To test this hypothesis several naphthenic acids and copper naphenates were obtained and their fungicidal activity against three wood-destroying fungi measured. In addition, the chemical structure of the naphthenic acids were examined by proton- and carbon- NMR. Different activities were observed, especially against a copper-tolerant fungus. Some apparent correlations were seen between the fungicidal activity and chemical structures for the few samples studied.
T Schultz, D D Nicholas, L L Ingram Jr, T H Fisher
How to Document the Performance of Super-Critical Treated Wood in above Ground Situations?
2005 - IRG/WP 05-20316
The paper presents practical experiences from the preparation of a new preservative treated wood product for introduction to the market. The product in question is Superwood™, which is treated with organic biocides using CO2 in a supercritical state as a solvent. The question is how to evaluate the performance of a new product such as Superwood™ in order to get an acceptance on the market and fulfil the formal requirements. In the European Union countries, the EN 599-1 is the standard that needs to be complied when approving a new product for the market, but it only focuses on the toxic limit against representative decay fungi according to EN 113. However, decay test, above ground and other forms of field tests are optional, this is not in line with the traditional test philosophy in the Scandinavian countries. The open question is to which extent treatment to the level of the toxic threshold value also ensures a long service life and expected performance of the treated commodity. Superwood™ is evaluated using a strategy, in which basic laboratory tests are done to get the toxic value (according to EN 599-1) and in addition a number of field tests are done including accelerated testing in the tropics. These tests are focussed on the evaluation of the performance criteria such as durability and service life and maintenance requirements. These questions must be answered by the producer without having a full record of performance test for their new products. A short status on the test performed on super-critical treated wood (Superwood™) is presented. Based on a comparison between field test in Scandinavia and in the tropical Malaysia a service life of more than 25 years for a specific supercritical treated product is estimated. It is stated that the existing European standardisation system is insufficient when it comes to service life prediction. A number of important questions need to be addressed by the European standardisation system as soon as possible because the market and the public opinion change quickly due to environmental concern.
N Morsing, A H H Wong, F Imsgard, O Henriksen
Improved techniques designed for evaluation of fungicides in soil for control of dry rot fungus Serpula lacrymans
1985 - IRG/WP 2238
Improved techniques provide a laboratory method for the evaluation of chemicals in soil for control of dry rot fungus Serpula lacrymans. Results with their application to three chemicals were reported. These techniques are useful to eliminate chemicals lacking the necessary toxicity and weatherbility for dry rot control when the chemicals have been applied to the soil.
M Takahashi, K Nishimoto
Progress towards controlling soft rot of treated hardwood poles in Australia
1977 - IRG/WP 289
Results of stake tests on wood preservatives (Progress report to 1974)
1975 - IRG/WP 361
A number of field stake trials on preservative-treated wood have been carried out at Princes Risborough Laboratory from 1928 to the present day, and many of the tests still continue. This paper presents in detail the results obtained to date, covering about 15 000 individual test stakes exposed over the period.
D F Purslow
Organic solvent preservatives. Essays on the ecotoxicology of new formulations
1991 - IRG/WP 3642
The knowledge on the ecotoxicological profile of wood preservatives become more and more important. The acute toxicity against aquatic organisms was examined for oil-borne preservatives, based on combinations of new fungicides (Tebuconazole, Propiconazole, Dichlofluanid) and insecticides (Permethrin, Cyfluthrin). These tests were conducted with fish, daphnia and algae. In principle the different formulations showed similar effects. The results of active ingredients and solvents confirmed the high sensitiveness of daphnia as test organisms. Criteria for hazards for the environment are presented and discussed.
Fungicidal activity of some organic solvents, copper carboxylates and their complexes with 2-aminoethanol
1997 - IRG/WP 97-30136
We evaluated the activity of eight organic solvents against wood - rotting fungus Trametes versicolor in order to choose the most appropriate one for rapid screening tests of some copper(II) carboxylates and their adducts with 2-aminoethanol. Their activity against the selected fungus was classified in the following order: chloroform > N,N-dimethylformamide > acetonitrile > methanol > dimethyl sulfoxide > ethanol > acetone. The non-polar white spirit did not dissolve in the growth medium and the results could not be directly compared with the results for other solvents. As an appropriate solvent for screening of the tested copper(II) carboxylates, dimethyl sulfoxide (DMSO) was chosen. Minimal inhibitory concentration against Trametes versicolor of the screened carboxylates was in the concentration range of 1x10-4 to 1x10-3 mol/l. Coordinated amine ligands slightly, and not significantly, decreased fungicidal properties of the tested carboxylates.
M Petric, F Pohleven
Problem of the treatment of dried sawn spruce building timbers with water-borne preservatives. Interim reports for discussion at the 4th Annual Meeting in West Berlin on 27 October 1972
1972 - IRG/WP 311
One of the most difficult technical problems facing the preservation industry is how to improve the treatment of refractory species of timber such as spruce. Its resistance to penetration, even under pressure' precludes its use for more hazardous service situations, and even in less severe conditions a higher level of treatment would be desirable. The importance of this subject led us to look once again at possible ways of improving treatment.
W Liese, J W W Morgan, T Hof, R O Ullevålseter
Respiration methods used to follow the decay of wood and the toximetric evaluation of wood preservatives
1975 - IRG/WP 249
When wood is attacked and decayed by fungi, wood substance and oxygen (02) are consumed, while carbon dioxide (CO2), water and heat are liberated. Early in the 1960's workers from England, Canada and Sweden began studying CO2 evolution, with respect to decay and its control using chemical preservatives, while in Germany and the USA O2 utilization was being similarly examined. Oxygen consumption measurements during the decay of wood were made mainly using pressure differential closed systems and were shown to be reasonably sensitive and a suitable reflection of the rate and extent of decay. Carbon dioxide measurements were made using titration, conductivity and gas-chromatographic methods. The last method appears to be the most useful, being applicable to open and closed systems, flexible in application, very sensitive over a thousand-fold concentration range change without switching, and easily automated. Its application to evaluating the toxicity of wood preservatives has been intensively studied and shown to give chemical toxic thresholds after only one third of the normal incubation time, which are similar to those based on the much longer conventional weight loss method.
R S Smith
Light organic solvent preservative treatment schedules for New Zealand-grown radiata pine
1986 - IRG/WP 3379
The influence of pressure differential and treatment time on preservative uptake and distribution in radiata pine heartwood and sapwood is investigated. Treatment schedules are defined which minimise solvent usage but ensure complete sapwood penetration and optimise heartwood penetration.
Light organic solvent preservative treatment of glue-laminated radiata pine
1986 - IRG/WP 3380
The high permeability of radiata pine (Pinus radiata D. Don) is associated with ray-tissue and in particular the cross-field pits linking ray-tissue to tracheids. This pathway is absent in the tangential grain direction, leading to poor preservative penetration when treatment is restricted to the radial face - for example, timber fabricated into glue-laminated beams.
A new ground-contact wide-spectrum organic wood preservative: DNBP
1986 - IRG/WP 3358
A new organic wood preservative, which 25 years field tests have proved to be of efficiency and effectiveness comparable to CCA wood preservatives for ground-contact applications, is presented. Physical and chemical tests, supporting the long term field test results as well as indicating the characteristics of this preservative, are also presented.
W E Conradie, A Pizzi
Extracellular layers of wood decay fungi and copper tolerance
1983 - IRG/WP 1180
Extracellular layers around the hyphae of brown, white and soft rot fungi have been examined using electron microscopy. These layers were isolated for identification. Particular interest was directed towards the extracellular layers of copper-tolerant soft rot fungi.
D M Francis, L E Leightley
Use of vermiculite as substrate in assays on phytotoxicity of treated wood
1989 - IRG/WP 3547
It is considered the possibility of using vermiculite instead of soil as substrate in assays on phytotoxicity of wood treated with preservatives for agricultural use. Three organic preservatives were used. It had been tested the behaviour of both, vermiculite and soil in case of preservative leaking due to a leach. So that, assays of germination with cucurbitaceous were carried out, mixing a dose of preservatives with both substrates.
M V Baonza Merino, D Franco
Scientific development for prolonging the service life of timbers by impregnating with creosote or organic solvent type preservatives in which additive has been incorporated
1977 - IRG/WP 382
Chemically impregnated wood has played a prominent part in the Telephone and Electricity Distribution Industry during the past century and there is no doubt that it will play an equally prominent part in the future. The reasons why wood poles and wooden, structures predominate, are that when adequately chemically impregnated with a recognised timber preservative to ensure the expected service life for the purpose envisaged, the timber is then fully protected against the ravages of wood destructive organisms. Furthermore, wood is endowed with many natural characteristics that make it a favourite pole and structural material. Its high strength, light weight, ability to absorb impact or shock from loads suddenly applied and ability to resist overloading for brief periods plus its well-known insulating qualities - all are important basic reasons for its predominance in pole line structure. The use of chemically impregnated timber often makes it possible to carry out a given construction programme at less cost, or to erect more structures for a given sum of money, than when more expensive construction materials are employed.
P R B D De Bruin
Effect of fatty acid removal on treatability of Douglas-fir
1993 - IRG/WP 93-40008
Treatment of Douglas-fir with chromated-copper-arsenate (CCA) poses a major challenge. Several hypotheses based on the anatomical aspects as well as chemical reactivity of the preservative formulations with cell wall constituents and deposits have been proposed. Techniques to prevent pit aspiration or slow fixation reactions have, however, not significantly improved treatment. The presence of high molecular weight fatty acids have been reported to be responsible for higher hydrophobicity in some wood species. These acids can react with Cu+2/Cr+3 ions to form insoluble metallic soaps, thereby immobilizing Cu/Cr and increasing wood hydrophobicity by a mechanism similar to that employed in paper sizing. The effect of fatty acids on treatability was explored by removing these components via several extraction methods. In general, extracted wood had higher gross solution absorptions and chemical retentions, but preservative penetration was largely unaffected. The results suggest that removal or disruption of fatty acids can improve treatability of Douglas-fir heartwood.
S Kumar, J J Morrell
The use of C CP/MAS NMR in the chemical identification of decayed and undecayed, tropical timber species
1984 - IRG/WP 1224
13C CP/MAS NMR was found to be an extremely powerful tool for elucidating the chemical composition of Eucalyptus maculata, Pinus elliottii and Alstonia scholaris. The differences in lignin composition were different for each timber and discussed in relation to decay caused by soft-rot and white rot fungi. In particular the presence of syringyl and guaiacyl lignin types are discussed.
L E Leightley
Tests on preservation of wood against marine borers
1976 - IRG/WP 417
The Instituto del Legno has carried out for some years a series of trials about the biodeterioration of wood in the sea. The investigations included the settlement and activity of marine borers, the natural durability of indigenous and tropical woods and the preservation of wood for marine use. This paper reports the trials on the effectiveness of some preservatives in protecting wood against marine borer attack. The trials were carried out at Follonica station, where some investigations had shown that untreated pine samples submerged in the sea were totally destroyed by marine borers within 1 year. Follonica station, latitude 42° 55' North and longitude 10° 45' East, is situated on the Tyrrhenian sea. The recorded temperature varies between 12°C (January to March) to 25°C (July to September), salinity between 37 to 38% and pH about 8. The borers observed in wood were: Nototeredo norvagica Spengler, Bankia carinata Gray, Limnoria tripunctata Menzies and Chelura terebrans Philippi.
A Gambetta, E Orlandi
A bibliography of organic solvent-based wood preservatives
1973 - IRG/WP 322
An insight into brown rot decay of timber as revealed by 13C CP/MAS NMR
1985 - IRG/WP 1259
L E Leightley
Bibliographie sur les produits organiques en solvant pour la préservation du bois
1971 - IRG/WP 38
Bibliography of organic solvent based wood preservatives
1971 - IRG/WP 38 E
This publication has as its objective the collection of the more important and more recent references dealing with solvent-based timber preservatives; these are often termed - sometimes wrongly - oil-borne preservatives or even organic wood preservatives. It is hoped that this review will stimulate more fundamental studies in the future in this field or on some of its aspects.
Collaborative tests on the influence of solvent and drying method on the toxic limit of wood preservatives against Basidiomycetes
1974 - IRG/WP 248
Seven institutes from five countries, Austria, England, France, Germany and the Netherlands have collaborated in a study on the influences of solvent and drying method on the toxic limits of wood preservatives against Basidiomycetes tested according to the agar-block method. Two preservatives, a 25% pentachlorophenol-concentrate and tributyltinoxide were applied to pine sapwood and beech and tested against Coniophora puteana. The preservatives were diluted with either acetone. benzene, chloroform or xylene. Slow drying in vapour of the solvent was used for all solvents. In addition quick drying was used for benzene and chloroform and freeze drying for benzene. The results were not conclusive regarding any influence of the solvent and drying method on the toxic limit. There was a trend that the toxic limit of the pentachlorophenol concentrate is decreased by the use of acetone as solvent. An influence of acetone on the toxic limit of tributyltinoxide could not be stated. The results regarding an influence of the drying method on the toxic limit of the preservatives were variable. There is some evidence that the toxic limits are lowered by freeze drying. As this effect is not present in all cases, the differences in the established toxic limits are probably due to normal variation in results and not associated with the drying method.