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An attempt to evaluate wood resistance against fungal decay in non-sterile conditions by measuring the variation of resistance to bending test
1988 - IRG/WP 2308
The main object of this work was to determine the variation of strength on large test specimens of wood (800 x 45 x 45 mm³) when exposed to accelerated fungal attacks close to natural conditions, out of test vessels. The modulus of elasticity (MOE) and the modulus of rupture (MOR) have been assessed. Thereby, the natural resistance of the wood species to fungal decay, the efficiency of preservative as well as the treatment applied are discussed. The wood tested is a guianese secondary species (Couma guianensis). The fungi tested are two guianese strains of brown and white rot. The exposure time is 12 weeks. No mould contamination has been recorded by use of a selective fungicide. The results obtained show that it is possible to infest in nonsterile conditions large wood specimens. Furthermore, modulus of rupture appears to be the most reliable criterion. The investigation, that requires limited equipment and staff could be performed in any tropical research station as it has been done at CTFT, French Guiana center.
L N Trong


The resistance of wood coated with different solvent-borne paints against colonisation by decay fungi
2009 - IRG/WP 09-40468
This paper examines different solvent-borne paints characteristics and their decay resistance when applied on pine wood surface. It was determined by the standard ENV 839 procedure. The part of samples were subjected to accelerated ageing according to the EN 84 standard. The discussed commercial paint systems were typical stains or penetrating oil-based products, with or without biocides.
B Mazela, P Hochmańska


Dimensional stability, biological resistance, and mechanical properties of phenol-resin-treated particleboard
1990 - IRG/WP 3622
Particleboards were treated with a low molecular-weight phenol-formaldehyde (PF) resin and their enhanced properties were evaluated. Besides dipping of particles in aqeous solutions of resin, and spraying of resin solutions before spray of the conventional phenol-formaldehyde resin for adhesive binder, one step treatment by spraying of the mixture of the low molecular-weight resin and the adhesive resin was also employed. After 2-hour boiling, the boards treated at 10% incorporated resin loading (IRL) retained 80% of their strength values in a dry condition. The internal bond strength increased with increasing IRLs, and the boards of 20% IRL showed twice of the value of untreated controls in the same level of board density. Treated particleboards resulted in a more dramatic reduction in the rate of swelling even at low resin loadings. Results obtained from accelerated laboratory tests on biodegradation suggested that incorporated resin-solids worked well to enhance decay and termite resistance of particleboards.
Y Imamura, H Kajita


Fungal resistance of smoke-dried Cryptomeria japonica wood
1998 - IRG/WP 98-40118
Performance of smoke dried wood on fungal resistance was studied. The maximum temperature of the smoke seasoning was 80-90°C in the drying room and 70-80°C within the wood for 6 days during the treatment for 15 days. Decay resistance of smoke-dried Cryptomeria japonica wood was evaluated using a brown rot fungus, Tyromyces palustris. Weight losses of untreated wood, smoke-dried wood, and smoke-dried wood followed by surface removal of 3 mm in thickness were 53%, 16%, and 21% respectively. After leaching for ten days, their weight losses were 38%, 51%, and 46% respectively. Smoke-dried wood had decay resistant some extent against the brown rot fungus, however its effectiveness disappeared completely during leaching. Smoke-drying did not have any effect on preventing the mould growth.
K Yamamoto, I Momohara, T Nishimura


Natural durability of Iranian saxual wood (Haloxylon persicum) against the fungal decay
1991 - IRG/WP 1515
Haloxylon persicum is vidly planted in the deserfic region of Iran. At the present time, in the age of 30, these small trees are ready for cutting for the different uses, specially for rural buildings. But there's any knowledge about its durability. In this study the laboratory tests were carried out in accordance to European Standard. 5 fungi were used as: Trametes versicolor, Coniophora puteana, Poria placenta, Gloeophyllum trabeum and Stereum hirsutum. The result show that the saxual wood can be classified as resistent. It has a service life of more than ten years exposed in a mediterranean climate. Therefore the use of round wood of converted wood for out side constructions such as f.ex. rural building can be recommended.
D Parsapajouh, F H Schweingruber, K Richter


Improvement of some technological and biological properties of poplar wood by impregnation with aqueous macromolecular compounds
1992 - IRG/WP 92-3721
Poplars (Populus spp) belong to the most important tree species in afforestation programs of the Netherlands. Due to their rapid growth, the wood quality is usually low. Therefore, studies were performed to elucidate whether some technological properties and the resistance against fungal attack could be improved by impregnation with water-soluble resins. The results showed that swelling and shrinkage of poplar wood may considerably be reduced by a treatment with certain resins. The anti-shrink efficiency (ASE) strongly depends upon the resin type. An air-curing alkydresin based on polybutadiene and an air-curing acrylate modified alkydresin emulsion caused the best effects. Additions of wood preservatives to the resins further improved the ASE. Some disadvatages of the tested resins may be seen in their leachability with consequent loss of the dimension-stabilizing effects. The resins by themselves don't reveal fungistatic properties but an impregnation of poplar wood with these materials led in all cases to a better durability against Coniophora puteana and Coriolus versicolor. Leaching procedures influenced the durability in various ways. With resin/fungicide combinations, a good resistance against Coriolus versicolor could be reached even after leaching. SEM and EDXA methods were used to localize the resins in the cell walls and lumina and to detect the growth of mycelium in the specimens.
R D Peek, H Militz, J J Kettenis


Fungal-termite associations in the natural resistance of selected eucalypt timbers
1978 - IRG/WP 173
Butt billets of Eucalyptus regnans F. Muell., Eucalyptus grandis W. Hill ex Maiden, and Eucalyptus camaldulensis Dehnh., showing no visible signs of decay, were examined for the presence of fungi in outer, middle and inner heartwood. Fungi obtained in pure culture were characterized. Eucalyptus regnans yielded Cytospora eucalypticola van der Westhuizen, Trichoderma harzianum Rifai and Penicillium spp.;·Eucalyptus grandis yielded Pesotum sp., Acrodontium sp. and Penicillium spp.; and Eucalyptus camaldulensis yielded only Penicillium spp. The natural termite resistance of the same billets was investigated, following decay (12 weeks) by brown-rot Gloeophyllum trabeum (Pers. ex Fr.) Murr., white-rot Fomes lividus (Kalch.) Sacc. and soft-rot Chaetomium globosum Kunze. Blocks were exposed to the termite Nasutitermes exitiosus (Hill) (Termitidae) under laboratory and field conditions to determine if there were significant, quantitative differences in (1) fungus-infested and uninfested blocks, (2) blocks containing living or dead fungus, (3) types of radial heartwood, and (4) species of timber. Clearly fungus-infested wood was preferred to the uninfested by Nasutitermes exitiosus, and dead fungus in wood to the living. Further there was pronounced radial variability, and timber species were also markedly different, although these differences could not be measured, for the presence of strong interactions. The interactions involved species of fungus and timber, species of fungus and type of radial heartwood, condition of fungus (dead or alive) and species of timber, and species of timber and radial heartwood. In the case of tyndallised (at 70°C) timber exposed to decay fungi only, similar interactions, involving species of fungus and timber, and species of fungus and type radial heartwood, were also evident. The interactions implied that fungal or termite resistance of wood was not only influenced by the inherent properties of a timber species, but also by type of heartwood, fungal species and condition of the fungus involved.
D B A Ruyooka


Curing conditions for a low formaldehyde etherificated melamine resin
1998 - IRG/WP 98-40108
Waterbased methanol etherificated melamine formaldehyde resins have the potential to increase the resistance of impregnated wood against wood destroying fungi. Previous studies indicated that the resin with the lowest formaldehyde content tested showed the best results regarding fungal resistance, dimensional stability and formaldehyde emissions after curing. In the present paper the influence of curing-time and curing-temperature of the resin with the lowest formaldehyde content is presented. It is demonstrated, that a sufficient curing of the resin requires temperatures in the range between 120-140°C for a period of several hours. The addition of pure urea leads to reduced formaldehyde emissions while the anti-fungal effect of the resins increases or remains the same.
D Lukowsky, R-D Peek, A O Rapp


Termite and fungal resistance of in situ polymerized tributyltin acrylate and acetylated Indonesian and USA wood
2000 - IRG/WP 00-30219
Wood [Indonesian pine (IP), Indonesian Jabon (IJ) and USA southern yellow pine (USP)] was either in situ polymerized with tributyltin acrylate (TBTA) or acetylated and then exposed to termite and fungal degradation both in laboratory tests and field exposure. The TBTA woods had an average weight percent gain (WPG) of 11% for IP, 12% for IJ, and 10% for USP. The acetylated woods had a WPG of 15-27% for IP, 16% for IJ, and 12-21% for USP. All levels of TBTA and acetylation treatments were effective against the brown-rot fungus Tyromyces palustris and the white-rot fungus Coriolus versicolor in laboratory testing. Resistance to subterranean termites [Coptotermes gestroi (Wasmann)] and dry wood termites [Cryptotermes cynocephalus (Light)] was shown in laboratory tests with all treatments. After one year of field testing in Indonesia (AWPA Standard E7-93), TBTA treated specimens gave a grade number of 8 for all 3 woods compared to 0 for the untreated controls (based on a 10 - point scale.) The acetylated specimens gave a grade number of 4 for IP, 8 for IJ, and 6 for USP. Scanning electron microscopy (SEM) showed polymer located in the lumen of the earlywood and latewood of selected TBTA treated specimens, but at low overall polymer weight gain the lumens were not evenly filled. Termite field testing continues on all treated wood specimens.
R E Ibach, Y S Hadi, D Nandika, S Yusuf, Y Indrayani


Factors affecting resistance to sapstain infection in freshly felled softwood logs
2003 - IRG/WP 03-10467
Previous studies in the UK have shown a marked difference in the susceptibility of logs of five softwood species to infection by sapstain fungi over a 4 month field trial. Recently this result has been confirmed and the rank order of greatest to least susceptibility in these commercially important species is lodgepole pine > Scots pine > Norway spruce > Japanese larch > Sitka spruce. Changes in moisture content and nutrient levels have also been assessed during the trial, as well as a study of differences in the resin composition of each wood species using GC-MS. Resin tapped from healthy, standing trees has been analysed and spectra derived from each species were compared. Resin formed at the edge of lesions on the outer sapwood surface, following inoculation of fresh billets with Sphaeropsis sapinea, has also been analysed. Factors influencing sapstain resistance are discussed.
E J Young, R A Eaton, J F Webber, M A W Hill


Evaluating the resistance of wood-based panel products to fungal attack
1995 - IRG/WP 95-20071
At present there is considerable disagreement among national research institutes within Europe and panel product manufacturers on the most appropriate method of testing and indeed the need for specific biological durability testing. This paper seeks to place before a broader international audience, the issues related to development of a European standard for evaluating the resistance to fungal decay of wood-based panel products. It rehearses the particular issues which need to be addressed. In particular it identifies as problems to be resolved, pre-conditioning of test samples to remove transient leachable/volatile preservative components, choice of weight loss or strength loss as efficacy criteria, and appropriate sampling levels.
R G Lea, R W Berry


The influence of staining fungi on the decay resistance of wood treated with alkylammonium compounds
1984 - IRG/WP 3308
Although found to be very effective in laboratory tests, alkylammonium compounds (AAC's) have failed to perform as well in field stake tests. Examination of leachability showed that this was not the cause. The present study investigated the possibility that staining fungi, (which have been observed to rapidly infect the field stakes), degrade the AAC wood preservative. Soil-blocks were treated with alkyldimethylbenzylammonium chloride, and sterilized, using gamma radiation. Half of the blocks were exposed to a mixed suspension of staining fungi, which had previously been isolated and identified from failed dialkyldimethylammonium chloride-treated stakes. After incubation for ten weeks they were conditioned, and one half leached in a static seven day leaching cycle. Half of the blocks not exposed to the staining fungi were also leached in a similar manner. All the blocks were then sterilized prior to exposing to one of three decay fungi, Lentinus lepideus, Gloeophyllum trabeum and Poria placenta. Following the test, Lentinus lepideus was found to be least tolerant to the AAC wood preservative, while Poria placenta was the most tolerant fungus. The Poria pre-exposure of the soil blocks to staining fungi greatly increased the toxic threshold and toxic limits of AAC to both Gloeophyllum trabeum and Poria placenta. The increases were almost independent of leaching, suggesting that degradation of the AAC is taking place rather than rupture of the AAC-wood substrate bonding. The increase in the toxic threshold to ca 9 kg/m³ would clearly have caused failure of the stake material in test at Westham Island, since the maximum concentration in that test was only ca 10 kg/m³.
J N R Ruddick


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


International comparison of three field methods for assessing the in-ground resistance of preservative-treated and untreated wood to termites and fungal decay – Summary of observations after five years
2003 - IRG/WP 03-20261
Results are presented from a five-year study conducted in five locations in Australia, Thailand and the USA. Three methods of exposure were assessed (below-ground, graveyard and ground contact) for evaluating the in-ground termite and decay resistance of Pinus radiata D. Don sapwood stakes that had been vacuum pressure impregnated with CCA (Type C) and ACQ (Type D) each at two nominal retentions (2 and 4 kg/m3), and of outer heartwood stakes from five trees of the durable North American Baldcypress, Taxodium distichum (L.) Rich. The termite attack and fungal decay ratings, based on the loss of cross section of the stakes, declined more rapidly at the three tropical sites in southern Thailand (Phuket) and in northern Australia (Darwin) compared to the two more temperate sites in southern USA (Gulfport, Mississippi) and southern Australia (Griffith, New South Wales). Depending on the type of preservative treatment (detailed for termites only) the three different assessment methods yielded either similar trends (ACQ 2 kg/m3; baldcypress) or outcomes varied with site and method (CCA 2 kg/m3; CCA 4 kg/m3) or the three assessment methods could be ranked from most to least effective in the same sequence across all sites (ACQ 4 kg/m3). Treatments or type of timber elicited different responses from the local termite fauna (from readily contacted by termites to avoidance). These responses can be modified by the way specimens are presented to termites. Average [n = 15] termite attack ratings (1st value Australian, 2nd value ASTM rating) after 5 years in the tropics (T) and non-tropics (NT) were: CCA 2 kg/m3 T = 4.3/6, NT = 6.7/8; CCA 4 kg/m3 T =5.5/7, NT = 7.4/9; ACQ 2 kg/m3 T = 4.4/6 , NT = 6.9/9; ACQ 4 kg/m3 T = 5.4/7, NT = 7.1/9. Baldcypress was more durable in the USA and Thailand (slight attack) and least durable against Mastotermes darwiniensis Froggatt in Australia (moderate attack). Fungus decay ratings (1st value Australian, 2nd value ASTM rating) after 5 years were: CCA 2 kg/ m3 T = 5.1/7, NT = 7.9/9; CCA 4 kg/m3 T = 6.1/8. NT = 7.8/9; ACQ 2 kg/m3 T = 5.2/7, NT = 6.7/9; ACQ 4 kg/m3 T = 5.6/8, NT = 7.7/9. Baldcypress results varied with source tree and test method.
M Lenz, J W Creffield, T A Evans, B M Kard, C Vongkaluang, Y Sornnuwat, A F Preston


Fungal decay resistance of Rubber wood treated with heartwood extract of Rosewood
2005 - IRG/WP 05-30367
Alcoholic extract of Dalbergia latifolia heartwood was studied for its toxicity towards wood decaying fungi. Rubber wood blocks were treated with this extract to three different retention levels (0.1%, 0.2% & 0.5%) and the treated wood blocks were assessed for their resistance towards two white rot and two brown rot fungi. Treated blocks showed improved resistance over the control blocks. At 0.5% retention level, treated rubber wood blocks exposed to fungus showed a weight loss of 15% as compared to 57 % in control blocks. A positive correlation was found between fungal decay resistance and retention level of the extract.
A K Sethy, H C Nagaveni, S Mohan, K T Chandrashekar


In situ testing the influence of melamine resins on the enzymatic activity of basidiomycetes
1999 - IRG/WP 99-30194
Waterbased methanol etherificated melamine formaldehyde resins have the potential to increase the resistance of impregnated wood against wood destroying fungi. The mechanism of the increased wood durability is not clear yet. In the present paper the possible interference of melamine resins with wood degrading enzymes of Coniophora puteana and Trametes versicolor was investigated as a possible contribution to the increased wood durability. An in situ photometric assay was used to measure the enzymatic activity against Walseth cellulose, pine sapwood as well as lignin and xylan preparations.
D Lukowsky, F Büschelberger, O Schmidt


Upgrading the fungal resistance of OSB
1999 - IRG/WP 99-40138
There is a perception that oriented strand board (OSB) is less resistant to fungl than plywood under conditions of moderate exposure to moisture. Douglas fir-faced plywood (DFP) has been suggested as a benchmark for acceptable durability under such conditions. This project was initiated to determine the minimum level of low-toxicity chemical treatment needed to upgrade the fungal resistance of OSB, made from aspen, to equal that of DFP. Against a brown-rot fungus in a soil-block test, 0.2% zinc borate (ZB), added during manufacture, and subsequent spray treatment with 10 µg/cm2 oxine copper provided the required performance. Against a white-rot fungus 0.2% ZB alone was sufficient and between 0.1 and 0.2% may have been adequate. For resistance to mould in a humidity chamber, spray treatment of OSB with 10 µg/cm2 oxine copper provided equivalent performance to DFP. The recommended combination of treatments for moderate moisture exposure is 0.2% zinc borate and 10 µg/cm2 oxine copper.
P I Morris, J E Clark, D Minchin, R Wellwood


Resistance of board materials against fungal decay: A comparative experiment on Kolle flask tests method and direct test method
1985 - IRG/WP 2243
Two sets of plywood (Aucoumea klaineana Pierre) 7 and 11 ply, treated by two preservatives, and untreated, were tested by two methods: 1. Kolle flask test method on malt-agar substrate according to the French standard NF B 51.295; 2. A direct test method in non sterile conditions according to DocNo: IRG/WP/2214. The exposure time far both methods was 12 weeks. After exposure, the degree of attack of the specimens was determined by static bending test. The statistic analysis of the average fracture stresses of different series showed that the direct test method was more reliable than Kolle flask test method.
G R Y Déon, L N Trong


Factors affecting the resistance of fibre building boards to fungal attack
1975 - IRG/WP 252
Fungal decay is initiated at lower moisture contents in standard and tempered hardboards (18%) than in pine sapwood (26%). In contrast, in a saturated atmosphere, the equilibrium moisture contents of standard hardboard (14%) and of tempered hardboard (12.5%) are much lower than the moisture content permitting decay initiation whilst the equilibrium moisture content of pine sapwood (25.1%) approaches its decay initiation level. When immersed in water the hardboard, especially when tempered, took much longer to wet to decay initiation moisture contents than the pine sapwood but, on the other hand, the hardboards dried at much the same rate as the solid wood. It is concluded that the physical changes which occur during hardboard manufacture are such that under fluctuating service conditions, even when liquid water is intermittently present, hardboards tend to remain at risk from fungal attack to a much lesser extent than solid wood.
C Grant, J G Savory


Laboratory methods for assessing the resistance of wood plastic composites to fungal attack.
2006 - IRG/WP 06-20340
Wood plastic composites (WPC’s) have many attractive material features including dimensional stability and resistance to moisture, but the wood in these materials remains susceptible to fungal attack. Assessing WPC decay resistance in laboratory trials has proven difficult because the slow moisture sorption characteristics of this material do not allow for sufficient fungal attack over the traditional test periods. In this report, the previous work on WPC durability is reviewed and the characteristics of these materials that might influence durability are discussed in relation to how the test methodology might be improved to produce more meaningful test data.
J J Morrell


Improvement of the Fungal Resistance of Japanese Cedar by the ThermoWood Process
2008 - IRG/WP 08-40422
The effect of the ThermoWood Process on sapwood of the Japanese cedar, Cryptomeria japonica, was investigated. Seven matched specimens were cut from a sapwood board of Japanese cedar and subjected to thermal treatments according to the ThermoWood Process. The decay resistance and chemical and physical properties of the treated specimens and untreated specimen were investigated. The decay test was carried out according to the Japan Industrial Standard K1571-2004. The specimens were cut to the size of 2 (R) ? 2 (T) ? 1 (L) cm or 2 (R) ? 2 (T) ? 10 (L) cm and subjected to the laboratory decay test and the fungus cellar test, respectively. The results of both tests clearly indicated that the ThermoWood Process at temperatures above 210 °C effectively increased the decay resistance of Japanese cedar sapwood. Mass loss was less than 13% in the sapwood treated at 220 °C for 2.5 hours, but was about 50% in the untreated specimens. Thermal treatments at higher temperature and for a longer period improved the decay resistance. No mass loss was found in the specimens treated at 237.5 °C for 5 hours. A similar tendency was observed in the fungus cellar test. The average decay rate of the untreated sample reached 4.6% after exposure for 0.6 year in the fungus cellar while that of the samples treated at 237.5 °C for 5 hours was still 0%. Determination of holocellulose contents suggested that the percentage of holocellulose was a good index for assessing the degree of thermal treatment and the level of decay resistance.
I Momohara, T Morita, S Shouho, A Yamaguchi


Fungal decay resistance and durability of wood products made from borax-impregnated wood and bonded with corn starch and tannin adhesive
2009 - IRG/WP 09-30494
At present, the production of wood composites mainly relies on the petrochemical-based and formaldehyde-based adhesives such as phenol formaldehyde (PF) resins and urea formaldehyde (UF) resins, which are non-renewable and therefore ultimately limited in supply. This paper concerns the decay resistance of wood products bonded with a new, environment-friendly adhesive derived from abundant and renewable cornstarch and tannin.To improve the total resistance of the composite against both Coriolus versicolor and Coniophora puteana rots fungi, borax (di-sodium tetraborate) was added in proportions of 0.5%, 1% and 2% (w/w) to the cornstarch-tannin adhesives. The results showed that increasing the concentration of borax in the adhesive decreased the mechanical properties of the composite. The best way to avoid this problem was to use wood impregnated with borax. Biodegradation studies were conduced on new composites, first without any treatment, followed by borax at 0.5 % aqueous solution treatment. The results show that wood impregnated with borax, in presence of tannin and sodium hydroxide in the adhesive improves the total resistance of the wood composite against both Coriolus versicolor and Coniophora puteana rot fungi.
A Moubarik, A Pizzi, A Allal, F Charrier, B Charrier


Synthesis of a rosin amide and its resistance to wood decay fungi
2009 - IRG/WP 09-30517
Rosin was reacted with diethyltriamine (DETA) after being modified by acryl acid with the weight ratio of 4.5:1 and a rosin amide (RA) derivative was produced at the conditions as follows: modified rosin and DETA mole ratio of 1:3.5, dimethylbenzene as water carrying agent, reaction temperature of 160-180°C, and reaction time of 8h. The chemical structure of the product as RA was identified by FTIR and MS analysis. The anti fungal activity of its derivative was determined by paper-disc method with wood decay fungi such as Coriolus versicolor, Gloeophyllum trabeum, Aspergillus niger and Paecilomyces variot Bainier. The anti-fungal experiment results signified that the derivative is active to these fungi, especially Paecilomyces variot Bainier. Since it is produced easily from rosin, which is renewable and not expensive, RA could be a potential wood preservative. Further study is planning.
Shuangyue Li, Shujun Li, Jing Wang


Fungal decay resistance and mechanical properties of plywood panels made from maritime pine (Pinus pinaster) and bonded with cornstarch-quebracho tannin-phenol formaldehyde adhesive
2010 - IRG/WP 10-40490
The aim of this work is to demonstrate the performances of cornstarch-quebracho tannin-based resins designed as adhesive in the plywood production. In this way, the cornstarch and quebracho tannin was introduced in the classic adhesive formulation in order to supply a part of phenol-formaldehyde (PF). In order to evaluate the mechanical performances of optimal cornstarch-quebracho tannin-PF, plywood panels were produced and mechanical properties were investigated. These mechanical properties included tensile strength, wood failure and 3-point bending strength. The biological performance of plywood panels against both Coriolus versicolor and Coniophora puteana rot fungi were evaluated. The performance of these panels is comparable to those of plywood panels commercial PF made. The results showed that plywood panels bonded with cornstarch-quebracho tannin-PF resins (15:5:80, w:w:w) exhibited better mechanical properties than plywood panels commercial PF made. The formaldehyde emission levels obtained from panels bonded with cornstarch-quebracho tannin-PF were lower to those obtained from panels bonded with control PF. Biodegradation studies show that the presence of quebracho tannin in the adhesive improves the total resistance of the plywood panels against both Coriolus versicolor and Coniophora puteana rot fungi.
F Charrier, A Moubarik, A Allal, A Pizzi, B Charrier


The chemistry of wood degradation by Basidiomycetes studied in a van Krevelen diagram
2013 - IRG/WP 13-10805
The atomic composition ratios of decayed wood by Basidiomycetes are mapped in a van Krevelen diagram. It is shown that the wood residue after decay is chemically reduced, rather than oxidized. A previously developed and verified theoretical model for thermal wood modification, relating atomic composition ratios to moisture sorption and fungal resistance properties has tentatively been applied to wood modification by Basidiomycetes-attack. It is argued that some of the reaction mechanisms, activated by heat during thermal modification, may also become activated in wood under fungal attack.
W Willems, H Militz


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