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Biological and chemical observation on the early fungal colonization of TBTO treated Swedish redwood stakes
1984 - IRG/WP 3311
Data on the early fungal colonization of Swedish redwood stakes, impregnated with 1% TBT0 / 0.5% dieldrin solution, both by double vacuum impregnation and immersion processes are presented. Results of chemical analyses of wood samples from the outer 1 mm of separate painted and unpainted stakes, exposed over the same twelve month period, are also discussed.
R Hill, A H Chapman, A Samuel, K Manners, G Morton

The formation of organotin carboxylates in bis(tributyltin) oxide - treated Pinus sylvestris sapwood
1990 - IRG/WP 3618
Tributyltin compounds have been successfully used for many years as wood preservatives, although their chemical nature in timber have not been fully elucidated. This study by 119Sn and 13C NMR spectroscopy has shown that, on impregnation into Pinus sylvestris sapwood, bis(tributyltin) oxide, (Bu3Sn)2O, is rapidly converted to tributyltin carboxylates, Bu3SnOCO·R, via reaction with components of the wood resin. It is further suggested that the formation of these species is a prerequisite for the known disproportionation reaction which occurs in (Bu3Sn)2O - treated timber.
S J Blunden, R Hill

Fungus cellar and stake tests with tall oil derivatives. Progress Report after 5 years' testing
1987 - IRG/WP 3442
Two derivatives of tall oils have been tested for five years in fungus cellar and stake tests. The samples were relatively quickly attacked on the surface by decay fungi, mainly soft rot, but the decay has progressed very slowly. The performance of the stakes in the tests has so far been equivalent or even better than some CCA preservatives and creosote.
J Jermer, Ö Bergman, T Nilsson

Fungus cellar and field tests with tall oil derivatives. Final report after 11 years' testing
1993 - IRG/WP 93-30007
Two derivatives of tall oil were tested as wood preservatives in a fungus cellar and in ground contact (field test). Stakes of Pinus sylvestris sapwood were used in the tests. For the field test the size of the stakes was 20 x 50 x 500 mm³ and for the fungus cellar test 20 x 20 x 250 mm³. The stakes were vacuum-pressure treated with the two products and exposed in 1981. The field test site used was in Uppsala, where the soil type is clay. In 1991 the last stakes in the field test were rejected and in 1992, the last stakes in the fungus cellar failed. The effect against biological degradation of the two products is compared with that of wood preservatives in current use.
J Jermer, Ö Bergman, T Nilsson

Preventive effectiveness of petroleum derivatives against blue-stain fungi. Part 2
1993 - IRG/WP 93-30001
Solvex-Tar, a product derived from the distillation of petroleum could be suitable for the treatment against blue-stain fungi in wood used in exterior carpentry, due to its effectiveness as a fungicide. The aim of this work has been to optimize the application of this product, modifying it as necessary, so as to improve its physical characteristics without interfering with its preventive effectiveness. To this end, six different Solvex-Tar based products have been tested, adding to them alkyd resin in different proportions, and toluene as solvent. The results demonstrate that the modification tested avoid its incompatibility with traditional coatings, decrease the viscosity and maintain its effectiveness against blue-stain fungi of wood in service.
E Sanchez, M T De Troya, A M Navarrete, A Guijarro

Low-toxicity DNBP wood preservatives
1987 - IRG/WP 3408
Low and very low toxicity single compound preservatives of both excellent insecticidal and fungicidal activity for interior, extrior and ground-contact applications are presented. These are ester derivatives of alkyl dinitrophenols, in particular of 2-sec-butyl-4,6-dinitrophenol (DNBP) and 2-sec-octyl-4,6-dinitrophenol. These esters, of much lower toxicity than DNBP impart to the treated timber comparable long term durability at much lower mammalian toxicity. These esters are shown in hydrolise to DNBP in the timber, explaining its long term durability.
A Pizzi, W E Conradie, A Jansen, R Vosloo

Preventive effectiveness of petrol derivatives against blue-stain fungi
1992 - IRG/WP 92-3716
A possible application of fractions obtained on petrol pyrolysis is their use as a wood preservative against wood-decay and sap-stain fungi. From two of these fractions were prepared three different products (ST, STL and SST). The aim of this work has been the possibility of utilizing these products in the treatment of wood used for external joinery, determining their effectiveness against blue-stain fungi and their compatibility with existing surface coatings. Test blocks of Pinus sylvestris and Pinus pinaster were used, treated with a brushed application of the above products, and then two different kinds of coating. The wood blocks were then exposed to 3 months of weathering. After this time they were placed in contact with pure cultures of Pullularia pullulans and Sclerophoma pityophila in sterile conditions, for 6 weeks. After the period of weathering the degree of varnish adherance was evaluated. The effectiveness of the preservatives was assesed by determining the penetration depth of the hypha into the wood face. The results obtained revealed that only ST and SST were effective against blue-stain fungi for wood in service, whereas the degree of compatibility with the coatings varied.
A M Navarrete, M T De Troya, E Sanchez, A Guijarro

Pentachlorophenol: The non-emotional approach. Second draft: A discussion document
1995 - IRG/WP 95-50040-07
Regulations on PENTA start from a strange story. Often initiated as pure ban in certain countries to provide satisfaction to pressure groups, the increased knowledge of the toxicology has contributed to one of the best documented file concerning a substance widely used as wood preservative. The accumulated documentation on its contaminants and its potentialities as dioxin and furan precursor in certain conditions justify an efficient pressure on initial quality, specifications, conditions of use and destruction. Are we actually able to draw practical conclusions from the enormous amount of work carried out in many countries to address the various questions raised by the chemical and its derivatives? The reply seems positive: the danger is actual, but some simple rules of use may reduce the probability of accidental situation to practically zero. The review explains in which way, regulations only based on intrinsic properties of substances, may appear totally blind if a practical risk/benefit analysis is not considered and proposes: specifications on tracers of impurities, classification of the dangers, identification of the most suitable form to minimize the risk, voluntary limitations of use for sensitive applications, rules of destruction and finally a standard of specifications socially acceptable worldwide.
G Ozanne

Pentachlorophenol, its salts and esters; UK review of its uses in wood preservation and surface biocides
1995 - IRG/WP 95-50040-27
The review on pentachlorophenol was undertaken by the Health and Safety Executive on behalf of the independent Advisory Committee on Pesticides in response to the 9th Amendment to the Marketing and Use Directive. The high toxicity to man and the environment was noted and the associated risks were assessed. The Cornmittee concluded that the potential carcinogenicity was probably via a non-genotoxic mechanism but required further information. It also recommended that the continued approval of the remaining products used in wood preservation did not pose an unacceptable risk to man or the environment because of the contained exposure. Thus further restrictions, beyond those required by the 9th Amendment, were considered unnecessary. However, there was evidence that intermittent high levels of PCP were detected around large chemical, petrochemical and steel manufacturers and industrial areas and these might warrant further investigation.
M Fitzpatrick, C Mackie

Breakdown of cellulose derivatives by cellulolytic enzymes. I. Action of fungal ß-glucosidases toward substituted PNP ß-D-glucopyranosides
1998 - IRG/WP 98-10281
The action of fungal ß-glucosidases on the methyl derivatives of p-nitrophenyl (PNP) ß-D-glucopyranoside, which were regioselectively substituted at 0-2, 0-3, 0-4 and 0-6 positions was studied. Several ß-glucosidases from brown-rot, white-rot, and soft-rot fungi and almond were used for the study. These ß-glucosidases did not act on the 2, 3, and 4-0-methyl derivatives, while the 6-0-methyl one was hydrolyzed by all the enzymes to some extent. The results indicate that the methyl group at 0-2, 0-3, 0-4 of the glucopyranoside strongly inhibits the recognition by the ß-glucosidases, while the enzymes do not discriminate the structure difference between PNP ß-glucopyranoside and its methyl derivative at 0-6.
T Nishimura, I Momohara, M Ishihara

Laboratory evaluation of borate amine: Copper derivatives in wood for fungal decay
2010 - IRG/WP 10-30543
The aims of this study were to evaluate borate: amine: copper derivatives in wood for fungal decay protection as well as the permanence of copper and boron in wood. Wood treated with each of four derivatives of borate:amine:copper prevented fungal decay. Disodium tetraborate ecahydrate (Borax):amine:copper derivatives with retentions of 0.61 to 0.63% after water leaching prevented decay by Gloeophylum trabeum (Gt) and 0.64% by Trametes versicolor (Tv). Leaching did not decrease decay resistance to both Gt and Tv. Disodium octaborate tetrahydrate(DOT):amine:copper derivatives with retentions of 1.14 to 2.93% after water leaching prevented decay by Gt and 0.54 to 1.19 % by Tv. Leaching decreased decay resistance to Gt but not to Tv. Higher copper and boron in disodium borax:amine:copper derivatives contributed to more decay resistance to Gt and Tv than that of DOT:amine:copper derivatives as evidenced by elemental analysis. Infrared spectra (IR ) of wood treated with 5% borate: amine: copper derivatives after water leaching showed that increased absorption at 1632-1635 cm-1 compared with the control. The increased absorption at 1632-1635 cm-1 was partly attributable to carbonyl of copper carboxylates from oxidation of hemiacetals of hemicelluloses and cellulose by copper (II) ions, and carbonyls of copper (II) quinone methides by oxidation of guaicyls by copper (II) ions. It was also partly attributable to carbonyls of copper carboxylates from hemicelluloses and phenolates from lignin through ion exchange reactions. The above oxidation and ion exchange reactions of copper with wood components may account for their efficacy and long term performance.
G Chen

The assessment of biological and mechanical properties of wood treated with ionic liquids – N,N-dimethylamine and 1-decylimidazole derivatives
2012 - IRG/WP 12-40582
This paper presents the results of tests of the effectiveness of action of new imidazolium and bis-ammonium ionic liquids against Basidiomycotina and Ascomycotina wood-destroying fungi. All the investigated ionic liquids showed high fungicidal action against Coniophora puteana. In order to characterize the influence of ionic liquids on mechanical wood properties, the compression strength along the grain was investigated. The obtained results showed that impregnation of Scots pine sapwood with ionic liquid: [1,9-(2,8 dioxanenano]bis(dimethyloctylammonium nitrate) had no negative effect on the compression strength parallel to grain. The investigated compounds characterised by thermal stability, may be applied as biologically active components of wood impregnates in combination with other biocides.
W Przybylska

Tall oil – performance after a decade of field exposure
2015 - IRG/WP 15-30672
Water repellents have the potential to enhance biocidal activity by reducing leaching and lowering the moisture levels in wood exposed to rains. A range of studies have been performed in order to evaluate the potentials of tall oils as wood protective systems. The general conclusion has been that tall oil can provide some protection but that they cannot compete with the copper and organic biocide based preservatives without adding additional active components. The aim of this study was to compare the performance of different tall oils in three different above ground field tests (mini stakes, block test and horizontal double layer - nine years exposure) and two in ground exposure trials (mini stakes and EN 252 – ten years exposure). The results show that for retentions of tall oils at 200-250 kg/m3 the treatment did to some extent delay the decay compared to control but it did not perform at the same level as the reference copper preservative. However, this study also shows that tall oil can perform well, even in soil contact, given high enough retention.
G Alfredsen, P-O Flæte

Development of beech wood thermo-chemical modification treatments based on different vinylic derivatives of glycerol and polyglycerol
2019 - IRG/WP 19-40855
In this study, a combination between chemical and thermal wood modification has been investigated. Seven types of a low concentration of 10% aqueous additive solution of vinylicglycerol [glycerol-maleic anhydride (Gly-MA), glycidyl methacrylate (GM), and Glycerol methacrylate-maleic anhydride (GM/MA(2eq))], vinylicpolyglycerol [polyglycerol-maleic anhydride (PG-MA), polyglycerol methacrylate (PGM), and polyglycerol methacrylate-maleic anhydride (PGM/MA(3eq))], and maleic anhydride (MA) were impregnated into European beech wood (Fagus sylvatica), known for its low dimensional stability and poor natural durability. Varied with different curing temperatures at 103, 150, 200, and 220oC under inert condition, the modified wood and control were then characterized for their physical, mechanical, decay, and termite resistance properties. We found that, at the same initial weight percent gain (WPG) value (8 – 11%), mass changes (∆m) after thermal treatment, bulking (B), weight loss due to leaching (WLL), swelling (S), wettability, modulus of elasticity (MOE), and modulus of rupture (MOR) values of the additive-treated wood decreased as the curing temperature increased. In contrast, anti-swelling efficiency (ASE), decay resistance against Coriolus versicolor, and termite resistance against Reticulitermes flavipes values of additive-treated wood increased considerably for some treatments as the curing temperature increased, with better results at 200 and 220oC. In other words, the study has disclosed that the addition of some selected additives combined with thermal treatment can improve wood decay resistance and termite resistance better than untreated wood or wood with only thermally modified treatment.
M Mubarok, S Dumarcay, H Militz, K Candelier, M-F Thevenon, P Gerardin

Potential of totora and derivatives as sustainable lignocellulosic material
2019 - IRG/WP 19-40859
Totora (Schoenoplectus californicus C.A. Mey. Soják) is a macrophyte from the Cyperaceae family that grows in the Americas from California to Chile. This plant has long been used by several cultures such as the Ohlone in California, the Moche in Peru, or the Incas in Los Andes. Some communities have maintained its traditional use until the present, such as the communities living nearby Lake San Pablo in Ecuador, or those living nearby Lake Titicaca in Peru and Bolivia. The most remarkable current example of totora use are in the Uros islands by Lake Titicaca. The Uros people have been using this plant for more than 500 years to build a wide range of objects from handicrafts to huts, and even the floating islands where they live. Some studies have shown the potential benefits of totora from a sustainability point of view. It is worth mentioning totora´s fast growing rate, which can be up to 56 t/ha/year of dry matter in rich substrates; that it can grow from the sea level to 4000 m.a.s.l.; and that it can grow in fresh water or estuaries; among other benefits. Despite the long tradition about the use of this plant as well as the previously mentioned potential benefits, its use in the contemporary context is still limited. The aim of this study was to evaluate the durability of the raw material and its derivatives against common wood-decaying organisms in accordance with the respective European Standards. Results have shown that although the raw material was not classified as durable, binderless fiberboards produced by using a hot-press forming process showed higher durability. These results may indicate the feasibility of using totora as a traditional material in contemporary applications with bio-economic and sustainable benefits.
J F Hidalgo-Cordero, D Casado, J García, L Robertson, M T Troya

Mechanical and biological durability properties against soft-rot and subterranean termite in the field (grave-yard test) of beech wood impregnated with different derivatives of glycerol or polyglycerol and maleic anhydride followed by thermal modification in an opened or in a closed system
2021 - IRG/WP 21-40917
This paper presents mechanical and biological durability properties in soil beg test (soft-rot test) and field test (grave-yard test) against subterranean termite of the wood modified with an aqueous vinylic derivative of glycerol/polyglycerol or maleic anhydride cured in an opened or in a closed system. Wood modification was performed through impregnation of European beech (Fagus sylvatica) with aqueous solution of polyglycerol maleate, glycerol maleate, or maleic anhydride at 10 or 20% w/w concentration, followed with curing under oven heating (OHT) at 120°C, 150°C, or 220°C in opened system or under heat pressurised steam (HPS) at 150°C in closed system. The modified woods were then characterized for their weight percent gain and mass losses after curing process, mechanical properties [modulus of elasticity (MOE), modulus of rupture (MOR), work to maximum load in bending (WMLB)], and biological durability properties against soft-rotting micro fungi in soil beg test and against subterranean termite (grave-yard test) in a tropical country. Results have revealed that almost all modified wood presented higher MOE values than untreated wood, however, MOR and WMLB decreased up to 27% and 87%, respectively. Biological durability in the soil beg test against soft-rot indicated that almost all modified wood were specified as durable to very durable wood. However, among the treatments, the wood modified with polyglycerol maleate/glycerol maleate/maleic anhydride at 20% under OHT 150°C or the wood modified at lower additive concentration (10%) under OHT 220°C presented significantly better durability against subterranean termite within a period of 328 days in the field.
M Mubarok, H Militz, S Dumarcay, I W Darmawan, Y S Hadi, P Gerardin