Your search resulted in 147 documents. Displaying 25 entries per page.
Efficacy of chitosan in combination with GRAS (Generally Recognised As Safe) compounds as a potential wood preservative
2007 - IRG/WP 07-30414
In vitro studies were undertaken to evaluate the synergy between chitosan and selected GRAS (Generally Recognised As Safe) compounds against two sapstain fungi Sphaeropsis sapinea and Leptographium procerum. Bioassays performed on nutrient medium suggested that some of the GRAS compounds tested including sodium benzoate, potassium sorbate and ascorbic acid had a synergistic effect when combined with chitosan against both test fungi. However the degree of activity varied depending on concentration used and species tested. Synergy between chitosan and sodium benzoate/or potassium sorbate was also apparent when bioassays were performed on sterile wood discs. After 3 weeks of incubation, discs dip-treated with either 1.5% chitosan or 0.5% sodium benzoate/or potassium sorbate had 60%-100% coverage by the test fungi. This was reduced to 5-10% fungal coverage on discs treated with the combination of chitosan and sodium benzoate and virtually no growth was observed on discs dip-treated with chitosan and potassium sorbate at the concentrations tested. Furthermore, fungicidal activity against S. sapinea was confirmed after re-culturing wood pieces taken from these discs on fresh malt-agar medium.
C Chittenden, K Thämelt, T Singh
Laboratory decay test of Burmese in and kanyin treated with three wood preservatives
1982 - IRG/WP 3210
Laboratory decay tests were performed on samples of In (Dipterocarpus tuberculatus Roxb.) and Kanyin (Dipterocarpus alatus Roxb. and Dipterocarpus turbinatus Gaertn f.) pressure treated with three wood preservatives - copper arsenic additive (CAA - a variation of ammoniacal copper arsenate), Arquad C-33 (a waterborne quaternary ammonium formulation), and tributyltin acetate (TBTA) dissolved in ethanol. Pressure treatments with each preservative involved a 0.5 - 1 hour vacuum followed by a 4 hour period of pressure. This resulted in a very variable treatment because of the inherent difficulty in treating these woods. The decay tests entailed a slightly modified form of the AWPA M10-77 standard soil-block test using three brown-rot and three white-rot fungi. The untreated In and Kanyin samples were moderately susceptible to decay though weight losses were very variable and some samples of Kanyin (usually the densest and least permeable) were naturally resistant. At the concentrations tested CAA was the most effective in reducing weight losses incurred in the soil-block tests. TBTA was successful in controlling decay caused by all but two of the test fungi. It is suggested that preservative retentions for TBTA conforming to those included in the Candadian standard for bis (tributyltin) oxide would exceed the toxic limit for all the fungi tested
J N R Ruddick, R S Smith, A Byrne
Chemical compounds from Eperua falcata and Eperua grandiflora heartwood and their biological activities against wood destroying fungus (Coriolus versicolor)
2005 - IRG/WP 05-30373
The chemistry analysis of the compounds present in dichloromethane and ethanolic fraction as well as bioassays enables to understand the durability differences of Eperua falcata and Eperua grandiflora. The principal distinction between these two species is the acidic subfraction of diterpenoic extract, which is antifungic in Eperua falcata when tested in in-vitro conditions. This study also enables to show that ethanolic fraction plays an important role in the mechanism of natural durability. It also reports the first isolation of cativic acid in Eperua falcata wood.
N Amusant, C Moretti, B Richard, E Prost, J M Nuzillard, M-F Thévenon
Observations on the colonization of freshly-felled timber treated with prophylactic chemicals by mould and sapstain fungi
1989 - IRG/WP 1394
Field tests using freshly felled pine sapwood were set up to determine the effectiveness of a range of antisapstain compounds and to study the problems of colonization by mould and sapstain fungi. Differences were recorded both in the overall performance of the compounds and also their selectivity in controlling specific fungal types. These results were found to be useful in gaining a better understanding of biocide - fungal interactions.
G R Williams, D A Lewis
Studies of the distribution and degradation of tributyltin naphthenate in double-vacuum treated wood
1983 - IRG/WP 3230
The effects of forced solvent evaporation by kilning redwood (Pinus sylvestris) that has been double-vacuum treated with tributyltin naphthenate (TBTN) have been investigated. Contrary to previous studies reported, it has been shown that forced evaporation can have a considerable influence on the losses of the fungicide. It has been found that, whether the solvent is allowed to evaporate slowly or the evaporation is forced by kilning, the TBTN breaks down considerably in freshly treated wood. In view of the implications of this work for the long-term effectiveness of TBTN further studies are called for.
J Jermer, M-L Edlund, W Hintze, S V Ohlsson
Fluorine compounds for wood preservation
1971 - IRG/WP 304
Fluoride compounds have gained a considerable importance in wood preservation, especially in Germany and some other countries of Europe. They are used as single compounde or in mixtures of different compounds. In the International Research Group on Wood Preservation which continues the activities of a former OECD-Group, it was moved to prepare a survey on fluorides in wood preservation together with other papers on the present state of knowledge of wood preservatives and methods of application. Monofluorides and silicofluorides have been used in the field of wood preservation for about 60 years and special development and application of hydrogen fluorides have been going on for 30 years. Much scientific work has been carried out on fluorides and much experience in practical use is available. It thus seems to be useful to briefly summarise the information on this group of compounds in wood preservation. Due to the voluminous literature, ie some 270 papers which are cited in the references, only an introduction into the problems and main results but not a detailed review of the publications is possible. The subjects dealt with in the publications are indicated in the references. With some exceptions the brief survey is limited to the compounds and mixtures without chromium which remain leachable in the wood. Questions of toxicity to human beings, animals and plants are not discussed in this paper.
Preliminary results of investigations on screening test of chemical compounds suitable for the preservation of lignocellulosic materials against biodeterioration
1976 - IRG/WP 262
This paper investigates the possibilities of reducing the time needed for the determination of the effectiveness of chemical compounds from the point of view of their eventual application to lignocellulosic materials for preservation against decay and soft-rot.
K Lutomski, S S Neyman
La rôle de l'expert dans l'évaluation toxicologique
1990 - IRG/WP 3589
The 1999-2000 annual report for the IRG - Wood Preservation in Egypt
2000 - IRG/WP 00-40188
The wood destroying insects in Egypt are belonging to several families of Coleoptera, Lepidoptera and Isoptera. Imported woods are treated by The Agricultural Quarantine or the authorized companies. The materials used for protection as pre-treatment are the same of the treatment. They are Bromide methyl, copper or fluoride salts, organo-phosphorus compounds, pyrethroides, creosote or creosodial. Any preservative should be evaluated by the Ministry of Agriculture before recommendation. Of the preserved woods are Lumbers, sleepers and poles, woods used in constructions and furniture as well. The woods used in furniture, constructions or woodworks are mostly imported from Sweden, Russia, Finland or Korea. Several kinds of woods are imported as Picea sp., Pinus sp., Phagus sp. Local woods used are limited in kinds and amount, as Casuarina sp., Eucalyptus sp., Ficus sp., Acacia sp. Treated woods are potentially increasing in use. There are neither restriction for the use of treated woods, not any regulation concerning the desposal of these woods.
S I M Moein
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
Analysis of organotin fungicides in wood preservative solutions and double-vacuum treated wood
1983 - IRG/WP 3250
A new analytical method using high-performance thin-layer chromatography (HPTLC), for the assay of organotin compounds in preservative-treated wood, is presented. The organotin compounds are extracted from the ground wood sample with a mixture of hydrochloric acid and ethanol. After HPTLC-separation, exposure of the thin-layer plate to ultraviolet light, and dipping of the plate into a 0.1% pyrocatechol-violet solution, the different organotin compounds are quantitated using a scanning densitometer.
W Hintze, S V Ohlsson
Dimensional stabilization of wood with dimethylol compounds
1987 - IRG/WP 3412
This study showed that a substantial degree of dimensional stability can be imparted to wood by crosslinking with low concentrations of dimethyloldihydroxyethyleneurea. It was demonstrated that by selecting the right catalyst system the cure temperature can be reduced to the point that strength loss of the treated wood is minimized.
D D Nicholas, A D Williams
Kinetic modelling of adsorption of quaternary ammonium compounds by Scots pine wood sawdust (Pinus sylvestris L.)
2005 - IRG/WP 05-30369
The adsorption of new quaternary ammonium compounds from aqueous solutions onto Scots pine wood (Pinus sylvestris L.) sawdust was studied. The pseudo first- and second- order kinetic models were used for the mathematical description of the sorption dynamic process of QACs onto wood. The highest correlation coefficients were obtained for the pseudo-second order kinetic model, those suggest that chemisorption is involved in the adsorption process.
Fungicidal and termiticidal effectiveness of alkylammonium compounds
1983 - IRG/WP 3232
This paper is related to effectiveness of several AAC's against wood decay fungi and termites by Japanese standardized test methods.
K Tsunoda, K Nishimoto
Some thoughts on the future strategy for eradicating Serpula lacrymans from a building
1989 - IRG/WP 1405
We now have a clear view of the mechanism of translocation of nutrients in the mycelium of Serpula lacrymans which is one of the physiological processes underlying the remarkable capacity of this fungus to spread through a building. Here the elements of the mechanism of translocation are dissected out to suggest avenues which might be followed in the search for new ways for eradicating the fungus from buildings.
D H Jennings
Editorial corrections to Document No: IRG/WP/304
1972 - IRG/WP 305
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
The Chemical and Biological Properties of Polymeric Betaine
2009 - IRG/WP 09-30512
Didecyl polyoxyethyl ammonium borate (DPAB), also known as Polymeric Betaine, was developed as a co-biocide for chromium-free copper based wood preservatives in Europe in the 1980’s. DPAB as a wood preservative has been reported previously. This paper summarizes the chemical, physical, and biological properties of DPAB.
H Härtner, S Schmitt, Futong Cui, H M Barnes
The rate of redistribution and loss of leachable preservatives under service conditions
1993 - IRG/WP 93-30026
This paper describes experiments carried out to determine patterns of preservative redistribution and any associated losses which occur when wood containing unfixed water-soluble wood preservatives is exposed to service conditions where leaching is possible. Scots pine sapwood treated with disodium octaborate was used as a model system. Results are recorded and discussed for trials representing painted joinery out of ground contact and unpainted stakes half buried in the ground. The results indicate that in the painted samples out of ground contact the water-soluble compound was redistributed longitudinally and away from the joint zone during the first months of exposure, although little redistribution occurred laterally. No difference in redistribution patterns could be associated with paint type. Ground contact stakes showed a loss in the water-soluble compound of about 40% in the first six months exposure. Most of this appeared to occur from the surface zones of the stake exposed to the weather, particularly from the extreme top. In addition, the compound appeared to migrate upwards from the below-ground portion of the stake to the above-ground portion. These results provide new information on the extent of movement of water-soluble preservatives in painted, jointed timber out of ground contact and in unpainted timber in ground contact. It is concluded that the long-term significance of the observed redistribution effects for painted joinery should be evaluated to confirm that there is no likelihood of shortcomings in performance in practice. For the ground contact situation, results confirm that rates of redistribution and loss are high enough to indicate inappropriateness of such materials for practical use without associated technologies to reduce mobilities.
R J Orsler, G E Holland
The performance of wood preservatives in soil-bed soft rot tests
1993 - IRG/WP 93-20007
Testing the efficacy of wood preservatives in soil is recognised as a fundamental part of the assessment of long-term wood protection in ground contact. Laboratory based tests can provide a hazardous environment in which a preservative can be challenged by a range of micro-organisms. This paper presents the results of tests carried out to investigate the performance of wood preservatives in a wet soil environment using both strength loss and weight loss as the main criteria for performance assessment.
G R Williams, S Caswell
Proposed degradation pathway for quaternary ammonium compounds by mould fungi
1996 - IRG/WP 96-10166
One group of chemicals that has attracted considerable attention as potential wood preservatives are the quaternary ammonium compounds (QACs). Based upon results of previous research this study confirmed the degradation pathway employed in QAC-tolerant fungi. For this experiment the two dialkylammonium compounds didecyldimethylammonnium chloride and dioctyldimethylammonium chloride were used. QAC-treated wood blocks were inoculated with the tolerant fungi Gliocladium roseum and Verticillium bulbillosum. After incubation the remaining QACs were extracted with acidified acetonitrilic and HPLC was used to quantify and detect the degradation products.
J L Bürgel, J Dubois, J N R Ruddick
Biological degradation resistance of pine wood treated with dimethylol compounds
1989 - IRG/WP 3528
The study reports the increase of dimensional stability and biological degradation resistance of pine wood (Pinus sylvestris L) after impregnation with dimethyloldibydroxyethyleneurea. Decay resistance was determined according to BS 838:961. Nearly complete protection against Coniophora puteana, (Schum.ex Fr. Karst) weight loss of 2-3% was shown when modification, expressed as weight gain, exceeded 15%. Resistance to biological attack of modified wood is speculated to be due to modification of the wood components and cross linking with dimethyloldihydroxyethyleneurea.
C L Videlov
Chemical analysis for TBTN in LOSP-treated wood and preservative fluids
1994 - IRG/WP 94-20027
Tributyltin napthenate (TBTN) is being substituted for tributyltin oxide (TBTO) in LOSP preservative formulations because its lower reactivity/better stability allows co-formulation with synthetic pyrethroids. Better stability may reduce molecular degradation both in-service and during analysis. It was considered necessary to check whether TBTO analysis methods were suitable for use on TBTN treated wood. Five analytical methods for TBTO in wood were applied to TBTN-treated pine sapwood, and evaluated for recovery, accuracy and precision. It was found that treated wood could be oven-dried before analysis, eliminating the need to run parallel moisture content determinations. The best performing method involved extraction of TBTN from oven-dry treated wood with acidified ethanol followed by AAS determination of tin. Performance was checked on freshly-treated and aged material.
D P Wraight, M J Kennedy
Stability and performance of tributyltin compounds
1984 - IRG/WP 3275
Based on the critical examinations of the disputable permanence of tributyltin compounds in wood, this paper deals with a number of examinations of the relative evaporation, thermal stability and oxidation stability of some TBT-compounds. While thermal and oxidative stability is high for all TBT-species, the relative evaporation at elevated temperature is highly variable, and lowest for the TBT-esters examined. Evaporation measurements on treated wood confirm this order of precedence and stress the importance of the preservative formulation. The results also indicate that TBTO evaporates 2-3 times faster than TBTN. It is established that at high retention of TBT in wood the decomposition is slower than at low retention. This fact combined with the extra high retention of TBT in vacuum treated joints of window frames explains the fine record of non-failure for such windows, and the paper ends up with a calculation indicating the presence of sufficiently high amounts of tributyltin for effective fungicidal protection of Nordic class B impregnated windows for at least 20 years.
F Imsgard, B Jensen, H A B Landsiedel, H Plum
Effects of terpene compounds on the growth and peroxidase activity of Phellinus pini
1979 - IRG/WP 2130
The volatile compounds myrcene, limonene, a-pinene, a-terpineol, D-fenchol and 1,8-cineole, present in the oleoresin fraction of coniferous wood, were tested individually and as mixtures for their effect on the growth and peroxidase activity of cultures of six strains of Phellinus pini (Fr.) A.Ames and one strain of Phellinus chrysoloma (Fr.) Donk (Phellinus pini var. abietis (Karst.) Pilát). Phellinus pini was more tolerant of the substances than Phellinus chrysoloma. There were differences in the tolerance and peroxidase activity between the strains of Phellinus pini. Peroxidase activity was generally higher in the test cultures than in the controls, but was lower in cultures exposed to 1,8-cineole and a-terpineol.