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High-energy multiple impact (HEMI)-test – Part 2: A mechanical test for the detection of fungal decay
2006 - IRG/WP 06-20339
The suitability of the high-energy multiple impact (HEMI)-test for detection of early fungal decay was examined. The HEMI – test characterizes the treatment quality of thermally modified wood by stressing the treated material by thousands of impacts of pounding steel balls. This method differentiates between heat treatment intensities, which are expressed by structural changes of the wood. Similar changes of the wood structure are known for wood decayed by fungi. Pine (Pinus sylvestris L.) decayed by brown rot and beech (Fagus sylvatica L.) decayed by white rot were tested. Mass loss caused by fungal decay and the resistance to impact milling (RIM) determined in HEMI-tests were found to be highly correlated. Testing of non-degraded pine, beech, and ash (Fraxinus excelsior L.) showed only marginal effects of wood density on RIM. Furthermore, annual ring angles and RIM of spruce (Picea abies Karst.) were found to be not correlated. Accordingly, the detection of strength reduction of decayed wood is not masked by variations in density and orientation of the annual rings. Previous results showed no adverse effects of weathering on RIM. Thus, the detection of fungal decay with HEMI-tests is feasible, not only for laboratory purposes, but also for wood in outdoor applications, which was already weathered.
C R Welzbacher, C Brischke, A O Rapp

High-energy multiple impact (HEMI)-test – Part 1: A new tool for quality control of thermally modified timber
2006 - IRG/WP 06-20346
Thermal modification processes improve durability and dimensional stability of wood, but the strength properties, especially the dynamic ones, are compromised and need to be considered with respect to industrial quality control. Results from standard dynamic strength testing, such as impact bending tests, suffer from high variability, and therefore require a high number of replicates. To overcome this, a new test method named high-energy multiple impact (HEMI) was developed. In the present paper heat treated beech (Fagus sylvatica L.), spruce (Picea abies Karst.), silver fir (Abies alba Mill.), and larch (Larix decidua Mill.) were investigated. The HEMI method is based on crushing small specimens by thousands of impacts of pounding steel balls in a heavy vibratory mill. The level of destruction was determined by slit sieving and analysing the size distribution of the fragments. We calculated the resistance to impact milling (RIM) based on the mass of the size fractions. RIM showed a linear correlation with the decrease in mass of the wood by the thermal treatment. The HEMI-test method has the following advantages: small number of specimens, short time for specimen preparation, small variances, high reproducibility of the results, and applicability to timber out of service for a subsequent quality control.
C Brischke, A O Rapp, C R Welzbacher

Effects of various preservative treatments on the mechanical and physical properties of plywood
1993 - IRG/WP 93-40007
The technical properties of plywood are related to both the intrinsic characteristics of its composing wood species and the quality and performance of the glue bond which acts as an interface between veneer sheets. Consequently mechanical and physical testing and glue bond strength analysis offer an appropriate means for studying the effect of preservative treatments on the overall quality of plywood. A range of boards was treated with waterborne and oilborne preservatives. Changes in modulus of elasticity, modulus of rupture and tensile strength were noted as well as variations in physical properties. Analysis of the glue bond strength was done by shear strength testing and determination of the amount of wood failure after different ageing procedures.
J Van Acker, M Stevens

Research on the effects of wood preservatives on the physical and mechanical properties of Iranian beech (Fagus orientalis Lipsky)
1985 - IRG/WP 3351
This research work was conducted with the aim of using preservatives such as Basilit and Wolman Salts with Iranian beech and to study any physical and mechanical changes these might have on the beech species of Iran. Samples were divided into three groups; one group were used as untreated controls, the second group was treated with Basilit and the third group was treated with Wolmanit. Results obtained according to the AFNOR French system of standards were: (1) After 140 days the moisture content of each group had reached 7.3%. (2) Samples with Wolmanit absorbed twice as much as those with Basilit and the two groups has some differences in specific gravity. (3) The volumetric shrinkage of wood preserved with Wolmanit was one fifth of that treated with Basilit. (4) In bending tests the samples treated with Wolmanit had more strength up to point of rupture than those preserved with Basilit. (5) The modulus of elasticity was more in samples preserved with Basilit than in those preserved with Wolmanit. (6) In compression parallel to the grain the samples impregnated with Basilit had more resistance than in those impregnated with Wolmanit. (7) In tension tests, the samples preserved with Basilit were stronger than those treated with Wolmanit. (8) In impact bending tests, the Basilit samples were stronger than the the Wolmanit ones. (9) In hardness tests, the resistance to indentation was less with the samples treated with Basilit than with those treated with Wolmanit; the Basilit seems to make the wood softer and from this result this type of treated wood could be recommended for use by carpenters and in woodworking shops.
P Niloufari

Heat treated timber in Finland
2000 - IRG/WP 00-40158
Heat treatment permanently changes the physical and chemical properties of wood by means of high temperatures (150 - 240°C). Heat treatment darkens the colour of the wood. Heat treatment improves the equilibrium moisture content of the wood and the shrinkage and swelling of the wood is reduced. Very high temperatures improve the resistance to rot and also reduce the susceptibility to fungal decay. At the same time the strength properties of the timber are reduced: the bending strength can fall by 30%, depending on the treatment conditions and the cleavage strength (tensile strength perpendicular to fibres) may be reduced to a half, which makes heat treated timber split easily. The improved characteristics of heat treated timber offer the timber product industry many potential and attractive new opportunities. Also wood species having no commercial value as such can be heat treated and in this way new uses can be found for these species.
T Syrjänen, E Kangas

Ancillary properties of vapor boron-treated composites
2001 - IRG/WP 01-40210
This paper discusses the water absorption, thickness swelling, and internal bond strength of North American composites treated using a vapor boron treatment process. For oriented strandboard, high boron loadings led to lower internal bond strength and lower thickness swelling. Water absorption results were variable but no deleterious effect of treatment was noted. For medium density fiberboard, the highest loadings led to reduced internal bond strength. Thickness swelling decreased with increasing boron level, but not significantly. As with OSB, water absorption results varied.
W A Jones, H M Barnes, R J Murphy

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

A Preliminary Report on the Properties of Engineered Wood Composite Panels Treated with Copper Naphthenate
2005 - IRG/WP 05-40294
This paper reports on our preliminary investigation of the properties of randomly oriented strandboard which had waterborne or powdered copper naphthenate (CuN) incorporated into the board during manufacture. When compared to zinc borate-treated controls (ZnB), the mechanical properties of strandboard (MOR, MOE, work-to-maximum load, internal bond strength) were not adversely affected by treatment with either form of copper naphthenate. In general, values for mechanical properties followed the trend untreated controls > waterborne CuN = powdered CuN > ZnB. Water absorption and dimensional properties followed a similar trend. This preliminary study suggests that CuN is a viable alternative treatment for engineered wood composites.
J W Kirkpatrick, H M Barnes

The effect of hemicellulose degradation on the mechanical properties of wood during brown rot decay
2001 - IRG/WP 01-20219
Incipient decay of wood by brown rot fungi causes measurable strength losses in wood before measurable weight loss occurs. Previous studies have shown that the high levels of strength loss that occur during incipient brown rot decay may be related to loss in hemicellulose. This paper investigates the effect of decay on hemicellulose composition and the relationship to the mechanical properties of the wood. An in vitro test method was used to allow progressive sampling of southern pine exposed to monocultures of a brown rot fungi. The wood was subsequently analysed by mechanical testing and chemical analysis. The results demonstrated a ratio of strength to weight loss of approximately 4:1. The chemical data indicated that early strength loss (up to 40%) was associated with loss of arabinan and galactan components. Subsequent strength loss (above 40%) was associated with the loss of the mannan and xylan components. Significant loss of glucan (representing cellulose) was only detected above 75% MOR loss.
S F Curling, C A Clausen, J E Winandy

Strength properties of preservative treated pine and spruce wood after super-heated steaming
1984 - IRG/WP 3313
Possible changes of strength properties of CCF pressure impregnated pine and spruce with subsequent steaming at 110°C respective 120°C for 30 min were examined. For spruce analysis of variance indicated that none of the processes had a significant effect on bending strength, compression strength and the corresponding modulus of elasticity as well as on impact bending strength and shear strength radial resp. tangential to the grain. For pine no changes in the bending strength and the compression strength could be detected. The impact bending strength of unsteamed or steamed impregnated samples decreased with 12% compared to non-treated controls due to the brittleness of the salt-impregnated timber. It could be proved that neither steam treatment of 110°C nor of 120°C for 30 min. alone causes a significant change of strength properties of pine and spruce. Arising variations can be explained from anatomical wood properties as well as salt deposits in the samples as a consequence to impregnation.
R-D Peek

Effects of alkali treatment on some mechanical and chemical properties of creosote treated oaks
1991 - IRG/WP 2366
To date, there is a lack of information on the effects of chemical treatment on the performance of creosote preservative treated oak sleepers. This factorial experiment was designed to analyze three main effects: species (Quercus alba and Quercus rubra) creosote treatment (treated and untreated), and alkali (NaOH) soaking (0, 1, and 10 percent). The modulus of elasticity (MOE) and fiber stress at proportional limit in compression perpendicular to grain, hardness modulus, surface hardness, alcohol-benzene extractives, hot-water extractives, 1% NaOH extractives, lignin, pentosans, holocellulose, and alpha-cellulose content were determined on specimens. The test results indicated that species, creosote treatment, and alkali soaking significantly affect both the mechanical and chemical properties of the oak sleepers.
P Chow, A J Reinschmidt, E J Barenberg, L C Chang

The effect of primary blue-staining fungi on the strength properties of Scots pine sapwood
2004 - IRG/WP 04-10515
The fungi action may have influence on wood properties especially Basidiomycotina fungi causing wood decay. The investigation of influence of fungi causing mainly wood discoloration and disfigurement on wood properties is still in development process. There were determined the differences between the bending strength, the compression along the grains and impact strength of control and blue stained sets of Scots pine (Pinus sylvestris L.) twin sapwood samples. The one part of each twin sapwood samples sets was exposed for 1, 3 or 12 months to the action of pure culture of blue staining fungi Ceratocystis penicillata, Cladosporium herbarum, Discula pinicola or their mixture while the second part of sets was control samples. Research showed that the changes in wood strength properties were dependent on the fungi action period and to get worse with the fungi action prolongation. The statistically significance of decreasing of sapwood properties was greater by impact strength and compression along the grains strength than by bending strength investigation. The level of decreasing the wood properties caused by blue-stain fungi during 12th months of their action was larger for impact strength (over –13%), smaller for compression along the grains strength (about –5-8%) and only very little (to –3%) and with less statistically significance for bending strength. The impact strength and compression along the grains strength appeared to be more sensitive indicators of the blue stain fungi action than bending strength.
A Fojutowski

Effect of vapour boron treatment on mechanical properties of wood based board materials
1992 - IRG/WP 92-3727
The mechanical properties of Medium density fibre board, Chipboard and Oriented strand board were investigated after treatment to two retention levels of boric acid applied as a vapour phase system. A range of mechanical properties were investigated. The vapour boron treatment does not have any significant effect on most of the mechanical properties of the boards. The exception is a reduction in impact strength especially at the higher retention level.
R Hashim, D J Dickinson, R J Murphy, J Dinwoodie

Supercritical fluid treatment: Effects on bending strength of white spruce heartwood
1993 - IRG/WP 93-20008
The effects of supercritical carbon dioxide on wood strength were evaluated using white spruce heartwood, a species known to be especially susceptible to collapse during exposure to higher pressures. The effects of pressures of 2000 or 3600 psig and temperatures of 40 or 80°C were evaluated using 30 or 60 minute exposure periods. No significant differences were noted in modulus of rupture or modulus of elasticity between specimens treated with supercritical fluid at selected pressures, temperatures or exposure periods or between treated and untreated control samples. Furthermore, no evidence of crushing or deformation were noted in specimens exposed to higher pressures. These results indicate that exposure to supercritical conditions should not adversely affect material properties of spruce.
S M Smith, J J Morrell, E Sahle-Demessie, K L Levien

Applicability of supercritical carbon dioxide to the preservative treatment of wood-based composites
2001 - IRG/WP 01-40199
Treatability of five structural-use wood-based composites (medium density fiberboard, hardwood plywood, softwood plywood, particleboard and oriented strand board) was evaluated when supercritical (SC) carbon dioxide (CO2) was used as a carrier solvent. Treatments were conducted at three temperature 32 levels (25, 35 and 45°C) and two pressure levels [80 kgf/cm2 (7,845 kPa) and 120 kgf/cm2 (11,768 kPa)]. Although small changes in weight and thickness of the wood-based composites were caused by treatments with SC-CO2, all treated materials did not sustain any physical damage. These results suggest that the treatment conditions provided the immediate penetration of SC-CO2 into the wood-based composites without any critical pressure gradient between outer and inner zones. Strength properties of the treated wood-based composites significantly improved after treatments in most cases. In contrast, a remarkable drop in strength properties occurred in oriented strand board specimens. Further studies are underway to determine the optimum treatment conditions using biocides incorporated into the mixing or treating vessel.
M Muin, A Adachi, K Tsunoda

Thermal modification of non-durable wood species 2. Improved wood properties of thermal treated wood
1998 - IRG/WP 98-40124
Properties of wood treated in a new heat-treatment process called the PLATO-process have been studied. Several wood species have been treated using this new thermal modification process using a range of process conditions (mainly time and temperature). In this study the characteristics of the treated wood were determined using samples from whole planks treated on pilot plant scale. The modified chemical structure of the wood after treatment results in a product with improved properties. The most important properties of wood, strength, dimensional stability and durability, were determined before and after the heat-treatment. The examined wood species showed a minor loss of strength after treatment. The correlation between the hygroscopicity of the treated wood in moist conditions and the dimensional stability has been studied. Depending on the applied process conditions the hygroscopicity of the treated wood decreased. The hygroscopicity was reduced by 40% and the dimensional stability appeared to have an improvement, ranging to 50%. The durability after heat-treatment was substantially improved.
B F Tjeerdsma, M J Boonstra, H Militz

Preservation of wood composites with zinc borate
1995 - IRG/WP 95-30074
Inorganic borates such as boric acid, borax, disodium octaborate tetrahydrate, and zinc borate can be incorporated into wood composites such as waferboard to impart decay and insect resistance to the final product. Zinc borate is especially well suited for this application due to its efficacy and leach resistance. The paper summarizes the work performed to date in this area. The effects on strength properties of the composite, water leach resistance of the borate, and effectiveness of the preservative treatment depends on the properties of the borate used and manufacturing variables such as adhesive type and content. In extensive work evaluating the properties of aspen waferboards bonded with pMDI adhesive, we have found that zinc borate performs well as a preservative additive. Such composites have excellent strength and water properties, as well as decay and termite resistance when appropriate levels of adhesive and borate are used. Further work is currently underway to evaluate the performance of zinc borate containing waferboard systems in severe ground contact applications. These types of products might be used in applications traditionally reserved for pressure treated solid wood and plywood.
P E Laks, M J Manning

The influence of causing primary blue-stain fungus Ceratocystis imperfecta on selected properties of Scots pine wood
2002 - IRG/WP 02-10425
The effects of development in wood the fungi causing blue-stain on the wood properties are not univocal. There were been undertaken investigation to clear the influence of such fungi on selected physical and mechanical properties of Scots pine wood. Wet sap wood samples of fresh cut Scots pine wood (Pinus sylvestris L.) were infested with pure culture of Ceratocystis imperfecta Mill. et Grenz and exposed into its action through 1, 3 and 12 month. The properties of the infested wood and their twin control samples were determined after each incubation period. The wood became the grey-black colour. The complete change of colour - ?E – measured by colorimetric Datacolor equipment was about 30 already after 1 month. The blue stain depth was from 1,0 mm - after 1 month to 5,0 mm (=whole cross - section) after 12 months. The absorptiveness of the stained wood greatly increased after 3 and 12 month of being infected by fungus. There was a tendency to drop the compression along the grains of blue stained wood in all investigated periods, but statistically essential changes appeared after only 12 months of the fungus action (mean drop 5%). The decrease of the impact of blue stained wood was statistically essential after 3 and 12 months of the fungus action (mean drop 13%). The statistically essential decrease in strength of wood was stated also by measuring of logarithmic decrement of torsional vibrations (mean drop 6%) and modulus of torsional rigidity (mean drop 2,5%). The stated changes in blue stained wood may to influence negative on usefulness of wood.
A Fojutowski

Mechanical properties of CCA-treated southern pine after post-treatment kiln drying
1989 - IRG/WP 3543
This report reviews current research dealing with the effects of waterborne preservative treatment and redrying on the mechanical properties of wood. In general, waterborne preservative treatments reduce average mechanical properties. This effect is exaggerated when treated wood is kiln-dried after treatment, especially at elevated temperatures. For lumber, recently completed research at the Mississippi Forest Products Laboratory (MFPL) and the US Forest Products Laboratory (USFPL) has shown that few negative treatment effects exist in the lower tails of the strength property distribution. An arbitrarily chosen -10% effect seems to begin somewhere between the 5th to 40th percentile of the strength distribution depending upon the grade of lumber and the severity of post-treatment redrying. As a result, the American Wood-Preservers' Association has recently initiated an across-the-board redrying temperature limit of 88°C (190°F) for all solid-sawn lumber and timbers. This report discusses recent research results and documents the reasoning behind the AWPA redrying temperature limit.
H M Barnes, J E Winandy

Physical and mechanical properties of tea (Thea sinensis L.), kanak chura (Peltophorum pterocarpum (DC.) Baker ex Heyne ) and bottle brush (Callistemon citrinus Stapf. ) - Timbers grown is Bangladesh
1999 - IRG/WP 99-40141
The physical and mechanical properties, especially the strength, density, structure, colour, natural durability, workability, seasonableness and treatability of timbers of tea (Thea sinensis), kanak chura (Peltophorum pterocarpum) and bottle brush (Callistemon citrinus) grown in Bangladesh have been found out for the first time. The tea and bottle brush are completely treatable at dry condition and also kiln-drying is easy but the heartwood of kanak chura is not pressure treatable and kiln-drying is moderately slow. The green modulus of rupture of tea, bottle brush and kanak chura timbers are 62 ±3%, 62 ±5% and 74 ±5% N/mm2 respectively. The former two are very suitable for small articles and the later one is suitable for all constructional works. The detected properties will enable these timbers to ensure various suitable applications.
A K Lahiry

Changes in some important mechanical and physical properties of untreated and treated mining timber after exposure to the conditions of a colliery
1996 - IRG/WP 96-20082
Each of salt treated and untreated mining timber (wedge) pairs with 5x15 cm² cross-section and 155 cm length prepared from Scots pine, Bornmüller's fir and oriental beech was cut in the small standard test specimens to determine changes in some important mechanical and physical properties, 13 month after exposure to the conditions of Kozlu Hard Coal Mines in the depth of 52 m. Thus, the method for determining the effects of decay on structural timber in service were described. Losses in impact bending, static bending and modulus of elasticity, and specific gravity were calculated as a percentage of the values for controls. Furthermore, relations between residual strength values and losses in specific gravity were statistically evaluated. Decreases in impact bending strength of all controls were ranged from 70% to 88%, in static bending strength from 71% to 73%, in modulus of elasticity from 50% to 56% while losses in specific gravity were ranged from 9% to 11%. The strength losses of wedge blocks treated with CCB salts were found between 3% and 6%, and changes in specific gravity were lower than 1%. Brown and white rot decay were determined on softwood and hardwood samples respectively.
A Bobat

Characteristics of treated oriented strand lumber using recycle chips
2006 - IRG/WP 06-40343
The Kyoto Protocol for preventing global warming has come into effect, and the Cabinet Council was decided on the amount of carbon dioxide exhaust to be reduced in Japan. Moreover, the recycling of demolition waste wood is mandated under the “Construction Material Recycling Law” as one of the mechanisms for Japan to form the recycling society. The law encourages the utilization of demolition waste wood as a raw material for wood-based panels as the main recycling method. However, because the amount of demolition waste wood generated from wooden houses is at least twice as high as the demand for wood-based panels, the development of new demand is needed to accomplish the goal. In this study, oriented strand lumber made from crushed demolition waste wood was developed, and the properties were examined. As a result, the developed oriented strand lumber had uniform physical properties, and preservative and anti-termite processing has no apparent detrimental effect. In order to evaluate the feasibility of the developed oriented strand board, it is necessary to consider the performance of nail joints and the effects of actual use conditions. When the materials are used in an actual structure, it is important to understand how the strength performance may change as a result of the conditions under which the structure was built, long-term use, and so on.
T Shibusawa, A Miyatake, K Yamamoto, K Hashimoto, H Sonobe

The effect of an ionic liquid of imidazolium tetrafluoroborates series on Scots pine wood properties
2007 - IRG/WP 07-40357
Ionic liquids (ILs) of imidazolium tetrafluoroborates series penetrate Scots pine wood very well and are active against wood destroying fungi. The requirement to use ILs as wood preservatives is determined by the liquid influence on the functional properties of wood. Investigations were undertaken to clarify the influence of an ionic liquid, 3-heptyloxymethyl-1-methylimidazolium tetrafluoroborate = [(C7Om)mim][BF4], on selected physical and mechanical properties of Scots pine (Pinus sylvestris L.) wood. The miniature sapwood samples were subjected to sorption and brushing with [(C7Om)mim][BF4]. The properties of the treated wood were compared with those of control wood, i.e. untreated wood. [(C7Om)mim][BF4] exerted only a very small influence on wood color – the total color change, ?E, amounted to about 5, which facilitated visual distinction of the wood texture, however, the color change of the treated wood was lower when irradiated with a xenon lamp. This demonstrated the resistance of IL-treated wood against color change at exposure to light. In comparison with control wood samples the IL-treated wood samples manifested also lower hygroscopic and absorptive potential. In addition, the relative differences in tensile strength, bending strength and modulus of elasticity between the treated and control samples were statistically insignificant. Compression strength along the grain of treated wood was greater by 1.6% than that of control wood, while the impact strength of treated wood was lower by 7.8% in comparison with control samples. The influence of [(C7Om)mim][BF4] treatment on physical and mechanical properties of wood, although insignificant, was generally positive if the IL is intended for biocidal protection.
A Fojutowski, R Szukala, J Pernak

Effects of Murgul Copper Process flue gases (SO2) on compression strength parallel to the grain of Beech (Fagus orientalis Lipsky.) wood
2008 - IRG/WP 08-40404
In this study was investigated the effect on the compression strength parallel to the grain as mechanical properties of Fagus orientalis Lipsky. wood exposed to SO2 gas and non-exposed. In the experiments the two of four (total) were obtained from Artvin-Ortaköy region and the other two from Artvin-Murgul region. The compression strength parallel to the grain was calculated at the compare of trees are taken from two distinct region. The obtained data of SO2 exposed specimens were compared with non-exposed ones. According to the obtained data of this study suggestions were given. At the end of study no effect of SO2 gas has been determined on the compression strength parallel to the grain of Fagus orientalis Lipsky. wood.
N Ay, E Topaloglu, A Uncu

The effect of treatments in boron steaming medium on boron leaching and strength properties of wood
2008 - IRG/WP 08-40409
The combined effect of boric acid impregnation together with boron steaming and steaming heat treatments were evaluated in this study. Boric acid pre-treated wood samples and untreated ones subjected to steaming heat and direct steaming treatment in a close reactor at 13 bar pressure and 180 ºC for 30 minutes. Compression strength parallel to grain of wood samples, leaching test and pH measurements were performed. Quantity of boron in leached and unleached wood samples was determined with ICP (Inductively Coupled Plasma). Retention values obtained in treatments were enough to protect wood against many wood degradation organisms. Approximately 32 kg/m3 and 2.52 to 14.1 kg/m3 retention was obtained in pre-treated samples with vacuum impregnation and treatments in boron steaming medium respectively. After the treatments, all of the samples got dark color and became more brittle due to thermal degradation of wood components. A significant decrease on the compression strength parallel to grain of wood samples was monitored especially subjected to direct steaming boron treatment. Depending on pre-treatment and applied second treatment, strength values were decreased with a range of 6 to 27% compared with controls. Since strong acidic conditions tend to catalyze hydrolysis, dehydration and oxidation reactions in wood that adversely effect the strength of wood, treatments at high temperature caused strength losses. Heat treatment had less degradation potential than steaming in the study. Treatments in boron steaming medium have no/little effect on boron release and almost all boron was leached from the wood samples. Only boron steamed samples decreased boron leaching with a 20% rate. Biological resistance tests are needed to evaluate the performance of the treatments in both leached and unleached samples.
E D Tomak, Ü C Yildiz, S Yildiz, E Pesman

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