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The susceptibility of acetylated Pinus radiata to mould and stain fungi
1992 - IRG/WP 92-1548
The aim of this investigation was to determine the effect of 5, 10, 15 and 20 percent acetylation weight gains on the susceptibility of Pinus radiata sapwood to mould and stain fungi, and to establish if an acrylic paint, an oil-based stain and a water repellant gave superior protection from fungal growth on wood treated to 20% acetylation weight gain, compared to untreated wood. One treatment set was tested using a modified anti-sapstain screening trial method, designed to give optimal conditions of relative humidity (>95%) and temperature (25°C) for mould growth. A second treatment set was exposed to the weather and assessed at 10, 21 and 40 weeks. The results showed that over the three week laboratory trial period, the rate of colonisation by mould fungi of Pinus radiata sapwood treated to 20% acetylation weight gain was significantly (P < 0.001) slower than on untreated wood. This was attributed to the lower availability of readily assimilated nutrients such as sugars and starch in acetylated wood. The rate of colonisation by mould fungi of acrylic-finished sapwood treated to 20% acetylation weight gain was significantly slower than on acrylic-finished untreated wood. Acetylation up to 20% weight gain conferred no protection from mould growth for test samples exposed to the weather. None of the finishes perfomed better on acetylated wood than non-acetylated wood when exposed to the weather.
R N Wakeling, D V Plackett, D R Cronshaw


Resistance of acrylic paints on wood against growth of the rot fungus Dacrymyces stillatus
1990 - IRG/WP 2345
In the last few years the presence of the rot fungus Dacrymyces stillatus has been repeatedly confirmed in external wood panels, particularly from wood painted with water based paints. A laboratory method for testing of the fungal resistance of paint films on wood has been developed.This method has been used to test the efficacy of the fungicides Parmetol DF 18 and Parmetol HF 25 against attack by Dacrymyces stillatus. Recent findings regarding factors of importance for fungal attack of painted wood are also discussed.
J Bjurman


Progress report on co-operative research project on L-joint testing
1983 - IRG/WP 2192
A F Bravery, D J Dickinson, M Fougerousse


Blue stain in service on wood surface coatings. Part 3: The nutritional capability of Aureobasidium pullulans compared to other fungi commonly isolated from wood surface coatings
1993 - IRG/WP 93-10035
The nutritional capability of Aureobasidium pullulans was previously examined, using agar plate tests, with regard to nutrient sources that are potentially available in fresh and weathered wood (Sharpe and Dickinson, 1992). This study compared these findings with the nutritional capability of four other fungi (Alternaria sp., Cladosporium cladosporoides, Stemphylium sp. and Trichoderma sp.) commonly isolated from wood surfaee coatings. The liquid culture techniques were used to assess the relative abilities of the fungi to utilise a range of simple sugars, wood sugar alcohols, hemicelluloses, cellulose and lignin degradation compounds. The observations were used to explain why Aureobasidium pullulans is able to occupy so successfully, often in monoculture, the wood-paint interface niche.
P R Sharpe, D J Dickinson


Leaching of components from water-borne paints and fungitoxic effects
1995 - IRG/WP 95-20062
Water-borne model paints, acrylics and alkyd emulsion paints, of known composition were leached according to a procedure modified in accordance with ASTM 6271.1. The effectiveness of fungicidal compounds in the painted specimens before and after leaching was evaluated with a biotest in which Penicillium brevicompactum was used as a test fungus. The leaching of the fungicide Troysan Polyphase according to the biotest varied to a high extent depending on differences in paint composition. Fungicide efficiency in relation to paint formulation and fungicide mobility in a paint film is briefly discussed.
J Bjurman


Studies on the destruction by marine borers of fishing boats along the north-eastern Black Sea coasts of Turkey
1980 - IRG/WP 451
Marine wood-boring organisms are attacking fishing boats along the northeastern coasts of the Black Sea, Turkey. The damage and the intensity of attack of Teredo navalis L in fishing boats were studied.
O A Sekendiz, R Ilhan


Blue stain in service on wood surface coatings. Part 2: The ability of Aureobasidium pullulans to penetrate wood surface coatings
1992 - IRG/WP 92-1557
The ability of Aureobasidium pullulans to penetrate seven different wood surface coatings was examined. Eight isolates of Aureobasidium pullulans were used. Following penetration, light microscopy was used to examine the effect of the fungus upon the coating, and growth at the wood-film interface. The fungus showed different growth capabilities with different types of surface coatings. Some isolates were able to penetrate alkyd based coatings, but were unable to grow in the film. In contrast, after penetration through latex based coatings several isolates were able to produce growth in the films themselves.
P R Sharpe, D J Dickinson


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


Maintaining the adoption of the equilibrium moisture content in timber by bifluorides under outdoor circumstance
1989 - IRG/WP 3541
A description is given of the practical application of bifluorides, f. ex. Diffusec in maintaining the adaption of the equilibrium moisture content in timber, as a result of a many years observation of treated timber under outdoor circumstances.
H F M Nijman


The window joinery test hut
1975 - IRG/WP 257
D F Purslow


End grain sealants for wood preservation studies
1985 - IRG/WP 3341
The results of tests with possible end grain sealants for wood preservation studies are reported. The epoxy resins used gave satisfactory performance on wet or dry Sitka spruce and have been used with success for diffusion treatment studies.
R J Murphy, N A Summers


Wood preservation in the Australian beekeeping industry
1988 - IRG/WP 3473
This paper reports the results of a survey of Australian commercial beekeepers working 200 or more hives in June/July 1985. Nine hundred and forty seven apiarists were asked to participate and to provide information on their wood preservation methods, painting procedures and maintenance of bee boxes. Three hundred and eighty-four apiarists returned completed questionnaires (41%). The main wood preservatives used are copper naphthenate solutions (45%), linseed oil (8%), copper chromated arsenate (3%), hot wax (9%), copper naphthenate solution in linseed oil (3%), linseed oil/wax mixtures (3%) and paint (23%). The majority of apiarists (96%) paint treated bee hives, but there is considerable variation in wood preservative treatment procedures and paint application. Most wood preservative treatments (95%) are of the &apos;do-it-yourself&apos; variety, radiata pine being the most utilized timber. The bottom boards of bee hives are considered the most susceptible to wood decay and subterranean termite damage, as are cleats, stands or any wood in ground contact.
P J Robinson, J R J French


How to keep coated wood structures sufficiently dry to avoid damage caused by rot
1991 - IRG/WP 2376
During the last ten years, a new type of problems with wood rot has emerged in Scandinavia. Thousands of houses have been damaged by wood rot attaching to the exterior wood panel. This paper provides an overview of finished and ongoing work in order to identify the cause of these problems. In field tests, the moisture conditions were measured in panels coated with different paint systems. The influence of the panel structure and end-grain sealing on the moisture balance was also studied. The results from these tests show a large difference in the moisture balance between panels with different exterior wood coatings. In laboratory tests, the transmission of water vapour through paint films was measured using a modified cup method, which provides more realistic conditions for coated wood than the common cup method. One interesting observation made in the studies reported here is that latex paints seem to be much more permeable at high levels of relative humidity than earlier research has shown.
S Hjort


Resistance of painted wood to mould fungi. Part 2. The effect of wood substrate and acrylate paint systems on mould growth
1997 - IRG/WP 97-10234
Resistance of acrylate paint systems on different types of pine and spruce sapwood to mould fungi was studied. Dipping into the preservative prior to painting, a primer with and without a fungicide (propiconazole + IPBC 0.50 + 0.2%) and a topcoat with and without a fungicide (propiconazole + IPBC 0.25 + 0.12%) were combinations of the treatments studied. The efficacy of the treatment systems varied, but the wood material also affected the ability of the paint systems to resist mould growth on the paint surface. The kiln-dried yellow surfaces of the pine and spruce sapwood were more susceptible to mould growth than the spruce surface sawn 10 mm below the original kiln-dried surface. On the resawn spruce material, the most effective treatments were free from mould growth after 26 weeks at RH 100%. However, the effect was markedly lower on the kiln-dried surfaces of pine and spruce sapwood. The influence of natural weathering on the mould growth will be a next stage of the study. The study is a part of a project CT94-2463 in the AIR programme of DG XII.
H Viitanen, P Ahola


Natural weathering of wood in a sunny climate effects on surface chemistry and paint adhesion
1997 - IRG/WP 97-20109
Radiata pine veneers and blocks were exposed to natural weathering under Australian summer conditions over a period of 30 days. Infrared spectroscopy revealed that there was perceptible surface delignification after 4 hours exposure, substantial surface delignification after 3 days exposure and almost complete surface delignification after 6 days. Viscometry determinations on holocellulose samples from weathered veneers and unweathered controls indicated significant depolymerisation of cellulose after short periods of weathering. A tape test was used to assess the adhesion of acrylic latex primers to weathered blocks. The adhesion of exterior acrylic primers decreased on weathered wood surfaces and was significantly lower on specimens that were weathered for 5 to 10 days. An oil-modified acrylic primer showed greater adhesion to weathered wood surfaces. Primer adhesion was lower on weathered radial surfaces than on similarly exposed tangential surfaces. The practical implications of these findings for the coating of exterior wood with acrylic latex primers and the development of photoprotective treatments for wood are discussed briefly.
P D Evans, P D Thay, K J Schmalzl


Distinguishing isolates of Aureobasidium on the basis of their ability to utilise lignin breakdown products as a sole carbon source
1996 - IRG/WP 96-10151
Wild isolates of Aureobasidium were obtained by dilution plating from a ca 20 year old painted pine window frame. Four isolates were obtained from the paint/wood interface region and four isolated from regions deep in the wood. The isolates were then used to inoculate liquid cultures containing ferulic acid, a lignin breakdown product, present as the sole carbon source. Ability of the isolates to use ferulate, judged by fungal yield, viable propagule count and absorbance at 280 nm (a measure of the aromatic&apos;s final concentration) was dependent on the site of isolation. Isolates from the paint/wood interface were consistently better at utilising ferulate than those isolated from deep in the wood and a possible reason for this is suggested.
M W Schoeman, D J Dickinson


Blue Stain Testing of Alkyd and Acrylic Stains
2003 - IRG/WP 03-20273
Resistance against blue stain of semi-transparent alkyd and acrylic stains was tested by both EN 152 and the so-called reverse exposure test methods. Comparison of the results, obtained by both methods was the most important aim of this study. As expected, performance of the water-borne acrylic paint was lower compared to protective effectiveness of the alkyd stain. This difference was even more pronounced when artificially accelerated aged samples were exposed. It seems that the reverse exposure method may give more distinctive results. In general, our results confirm previous literature reports on adequacy of the reverse test method for evaluation of blue stain resistance of surface finishes.
M Petric, M Pavlic, B Kricej, M Humar, F Pohleven


Blue stain in service on wood surface coatings. Part 1: The nutritional requirements of Aureobasidium pullulans
1992 - IRG/WP 92-1556
The nutritional requirements of Aureobasidium pullulans was examined with regard to nutrient sources that are potentially available in fresh and weathered wood. The study was designed to determine how far wood cell wall components need to be broken down during weathering before they provide a useful nutrient source for Aureobasidium pullulans. Various carbon sources were tested, with eight different isolates of Aureobasidium pullulans. It was found that the organism could utilise the simple sugars well, but not the oligosaccharides. The organism was also able to utilise well several lignin precursor compounds.
P R Sharpe, D J Dickinson


Performance of preservative-treated wood not in ground contact
1975 - IRG/WP 254
Experimental sash units of Pinus strobus L. and Pinus resinosa Ait. wood were removed from a test fence at Ottawa, Canada after outdoor exposure of over 20 years. The units were superficially treated, prior to painting, with preservatives containing either copper naphthenate, pentachlorophenol or a combination of zinc naphthenate and pentachlorophenol. Results indicated that all treatments were effective in reducing incidence of decay. Unpainted controls were badly deteriorated. Painted controls deteriorated less, indicating that paint can provide some measure of protection. Nails were corroded to various degrees in wood treated with all preservatives except for wood treated with the zinc naphthenate-pentachlorophenol mixture. In this case nails were free from obvious corrosion and held the wood firmly. Evaluation of 20 years&apos; observation shows that a 10-year exposure should give adequate results on the effectiveness of a preservative system.
J K Shields, J Krzyzewski


Results on field stake tests against termite – Maximum for 8 years examination at Kumamoto in Japan
2003 - IRG/WP 03-10463
Various preservative treated or modified wood and charcoal painting stakes were tested in field, maximum for eight years in Kumamoto, distributed two main termite species, Coptotermes formosanus and Reticulitermes speratus. After two years in field, untreated sapwood of sugi (Cryptomeria japonica) were observed severe attacks by termites, but the preservative treated stakes were observed no significant attacks by termites. After eight years experiment, treated stakes with preservatives not included copper, like DDAC and zinc-naphthenate, were observed slight or moderate attacks by termites. Otherwise, in the case of treated stakes with preservatives included copper, like ACQ, copper naphthenate and Tanalith CuAz, no significant attacks by termites were observed. Few samples of chemically modified wood or LVL were observed slight attacks by termites for seven years.
K Suzuki


Decay and termite resistance of wood treated with boron-containing quaternary ammonia compound, didecyl dimethyl ammonium tetrafluoroborate (DBF) incorporated with acryl-silicon type resin
2004 - IRG/WP 04-30334
This study evaluates the decay and termite resistance of surface-treated wood with didecyl dimethyl ammonium tetrafluoroborate (DBF) incorporated with acryl-silicon type resin emulsion. DBF is a quaternary ammonia compound and contains boric tetrafluoride (BF4-) as a counter ion in its chemical structure. In the study, DBF was incorporated with an acryl-silicon type resin to increase water-resistant of the preservative solution, and, in turn, to increase decay and termite resistance of surface-treated wood after severe weathering processes. Laboratory decay resistance tests were performed using brown-rot fungus Fomitopsis palustris and white-rot fungus, Trametes versicolor. Treated wood specimens were also subjected a 3-week-termite resistance tests using subterranean termites, Coptotermes formosanus. Wood specimens surface-treated with preservative solution including 2% DBF and the resin showed decay resistance against both F. palustris and T.versicolor even after severe weathering. Results suggested that treatment with DBF at 2% or greater concentrations containing acryl-silicon type resin emulsion would protect wood used outdoors against both fungal decay and termite attack.
S N Kartal, W J Hwang, K Shinoda, Y Imamura


The efficacy of polymer/preservative treatments in soil-bed exposure
1992 - IRG/WP 92-3729
Southern pine was treated with CCA, CCB, sodium borax/boric acid, or disodiumoctaborate, alone or in combination with an acrylic polymer system containing a water repellent. Treated samples were subjected to an unsterile soil burial test. The addition of polymer reduced the weight loss in borontreated samples at the lower retentions but not at the higher retention. Results with borates indicate that polymers may improve performance in above-ground applications. Polymer treatments improved the performance of CCA and CCB at retentions below threshold, indicating the potential for modifying CCA/CCB formulations.
R J Murphy, H M Barnes, S M Gray


Preservatives stains as exterior wood finishes
1977 - IRG/WP 389
For many years wood preservatives and paints have been used as the only treatment for exposed wood surfaces. Because of the inherent color of the preservatives, such as creosote, the wood surface was stained as well as protected from attack by micro-organisms. Paints protect surfaces from weathering, but recently, with an increased interest in maintaining the more natural appearance of exterior wood surfaces, painting is being replaced by staining. Stains have the advantages, in addition to preserving the natural wood appearance, that they do not peel, blister or crack, can be applied easily and renewed with little difficulty. The cost is less than that of paint, initially and over the life of the building. One of the major attractions for homes is that stains blend in with the environment. If the home owner desires a white exterior or bright colors, paint rather than a preservative stain must be used. Paints are more effective in protecting the wood from damage by sunlight and will avoid discoloration of the exterior surface resulting from the natural extractives present in wood. Special aluminium or stainless steel nails are not needed with paints, but are needed with stains. Preservative stains can be classified in various ways. Wood preservatives, such as creosote and pentachlorophenol, have been used for many years primarily for preventing deterioration caused by fungi, including fungus species which discolor and those that decay the wood. These compounds provided some degree of water repellency, but this was not a major objective in their use. Later, water repellents were added to the preservatives to reduce the rapid uptake of moisture and thus provide some dimensional stability to the product. More recently water solutions of inorganic salts have demonstrated that they provide protection to the wood, add color and are beneficial primary treatments if the wood surface is to be painted. Some of the water soluble formulations may provide some fire retardant properties as well. A common system of classification today includes three general types of natural finishes as follows: 1. water-repellent preservatives; 2. pigmented penetrating stains; 3. inorganic water soluble salts. It is possible to obtain a satisfactory exterior surface if no treatment is applied. Such an approach, however, is satisfactory only where the weather is not favorable for micro-organisms. If the fungi and other micro-organisms are allowed to develop, the coloring will be very nonuniform, the wood surface will deteriorate, and warping and the like will occur to excessive degrees. Thus in most environments one of the above systems must be used.
D W French


Chemical and biological investigations of double-vacuum treated windows after 7½ years in service
1985 - IRG/WP 3339
Earlier investigations of double-vacuum treated windows after five years in service have shown that tributyltin oxide (TBTO) degrades to di- and monobutyltin compounds and that the resistance of the wood against decay decreases. An investigation 2.5 years later of the same windows shows that the degradation of TBTO proceeds fast. After 7.5 years in service only 15-35% of the remaining organotin compounds consisted of TBTO. A clear correlation between the percentage of TBTO in the wood and decay resistance of the wood was found.
M-L Edlund, J Jermer, B Henningsson, W Hintze


Solution stability and Mechanical properties of Chitosan treated Pine
2005 - IRG/WP 05-30377
During the last years the research on chitosan as a wood preservative has been enhanced. Up to now, most of the research has been applied to the anti-fungal properties of chitosan, and no research was conducted on the solution stability of chitosan solutions in repeated trials by impregnation of wood, or on the mechanical properties of chitosan-treated wood. In this paper, the stability of high- and low-molecular weight chitosan solutions (2,4% (w/v) concentration) was investigated in 15 repeated impregnation cycles using pine (Pinus sylvestris) samples. Changes in the following parameters of the treatment solution were examined: uptake of chitosan, viscosity, pH, molecular weight and concentration. In addition, the following mechanical properties of chitosan-treated pine were determined using a paired experimental design: modulus of elasticity (MOE), static bending, impact bending strength, static hardness, shear strength, tensile strength, compression strength and adhesion of paint to wood. Overall, an average chitosan uptake by the pine samples in the order of 15 to 16 kg/m³ was obtained. In the trials for determination of solution stability, the uptake, viscosity and concentration remained unchanged. However, the pH of the solutions increased, and the average chitosan molecular weight decreased, with the high molecular weight chitosan displaying larger changes than low molecular weight chitosan. No significant changes in the mechanical properties of pine treated with high-and low molecular weight chitosan (2,4% (w/v) concentration) were determined as compared to untreated wood samples.
E Larnøy, M Eikenes, H Militz


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