Impacts of impregnation chemicals on combustion properties of the laminated wood materials produced combination of beech and poplar veneers

The aim of this study was to investigate the effects of impregnation with boron compounds Borax (B_X), Boric acid (B_A), B_X + B_A, Imersol-Aqua (I_AQUA) and Timbercare-Aqua (T_AQUA) on combustion properties of the laminated wood materials produced combination of Oriental beech and poplar veneers bonded with Desmodur-VTKA (D_V) and Poly(vinyl acetate) (P_VAc) adhesives. The test samples, prepared from beech (Fagus orientalis Lipsky) and poplar (Populus nigra Lipsky) woods, were impregnated boron compounds by vacuum, I_AQUA by dipping and T_AQUA by brushing methods according to ASTM D 1413-76-99 and directions of the manufacturer. The laminated wood materials were prepared in the form of five layers, 4 mm thickness from the impregnated beech and poplar veneers according to TS EN 386. Combustion properties of samples after laminated and impregnated process were determined according to ASTM E 160-50. Considering the interaction of combustion type and impregnation materials, combustion temperature was found the highest in flame source combustion (F_SC) + T_AQUA (528.150 °C) but the lowest in without flame source combustion (WF_SC) + B_A (391.333 °C). Consequently, boron compounds and I_AQUA showed a decreasing impact on combustion properties of the laminated wood materials, produced combination of beech and poplar veneers, bonded with D_V. In consequence, impregnation with boron compounds and Imersol-Aqua of the laminated wood materials, bonded with Desmodur-VTKA, provides security for the usage of having high risk of fire.     

Effects of impregnation with Imersol-aqua on the modulus of elasticity in bending of laminated wood materials

The aim of this study was to investigate the impacts of impregnation with Imersol-aqua on the modulus of elasticity in bending (MOE) of some laminated wood materials. For this aim, oriental beech (Fagus orientalis Lipsky), oak (Quercus petrea Liebl.), Scotch pine (Pinus sylvestris Lipsky), oriental spruce (Picea orientalis Lipsky) and Uludağ fir (Abies bornmülleriana Lipsky) wood materials impregnated with Imersol-aqua according to ASTM D 1413-99 and producers’ definition. Laminated wood samples were produced from impregnated wood materials according to TS EN 386 in the five ply form (4 mm each) from oriental beech, oak, Scotch pine, Uludağ fir and oriental spruce wood by using Desmodur-VTKA adhesive. The MOE values were measured according to TS EN 408. Consequently, the MOE of impregnated + laminated (I + L_W) softwoods, pine, spruce and fir increased, respectively by 8.07%, 2.62% and 2.45% whereas the MOE of laminated + laminated hardwoods, beech and oak decreased, respectively by 5.06% and 4.37% with respect to laminated control samples (L_W). Considering the interaction of wood type and process, the MOE was obtained from laminated oriental beech, whereas the lowest was found for impregnated Uludağ fir. In consequence, in the massive construction and furniture elements that the MOE after the impregnation and lamination (I + L_W) is of great concern, oriental beech and Scotch pine materials could be recommended.     

Structural performance of the finger-jointed strength of some wood species with different joint configurations

This study was conducted to evaluate the effects of adhesive type, wood species, and finger joint configurations on structural performance of the finger joint. The wood species studied were oriental beech (Fagus orientalis lipsky.), oak (Quercus robur), Scots pine (Pinus sylvestris lipsky.), poplar (Populus tremula lipsk.) and Uludağ fir (Abies bormülleriana Matff.) and adhesives were poly(vinyl acetate) (PVAc), Desmodur-VTKA (D-VTKA). However, there is little information available concerning the bending strength and modulus of elasticity for finger joints in these field. In this study, it was aimed to determine the bending strength and modulus of elasticity for finger joints. For this purpose, samples were tested according to the TS EN 310 standard. It was observed that the highest bending strength and modulus of elasticity were obtained in beech control (solid wood) samples. As for the finger joints, after the control samples, the highest bending strength value (57.4 N/mm²) was obtained from Oriental beech wood samples having a 21 mm finger length and bonded with PVAc adhesive, the highest modulus of elasticity (8885.3 N/mm²) was obtained from beech wood samples having a 21 mm finger length and bonded with PVAc adhesive. As a result of the effects of finger joints on bending strength and modulus elasticity test, if the length of finger joints increases up to 21 mm, the properties of bending strength increase.     

Some mechanical properties and decay resistance of wood impregnated with environmentally-friendly borates

This study was made to determine some mechanical properties such as compression strength parallel to grain, modulus of rupture, and decay resistance of wood treated with some environmentally-friendly borates. Sodium tetrafluoroborate (SFB), ammonium tetrafluoroborate, (AFB), and ammonium pentaborate octahydrate (APB) were used as borates. Wood specimens were prepared from Oriental beech (Fagus orientalis L.) and Scots pine (Pinus sylvestris L.). Before tests, wood specimens were impregnated with aqueous solutions (0.25%, 0.50%, 1.50%, and 3.00%) of borates according to ASTM D 1413-76.Results showed that compression strength parallel to grain (CSPG) and modulus of rupture (MOR) of wood specimens treated with borates were lower compared to untreated control specimen. In general, our results showed that the higher concentration levels of borates, the lower mechanical properties of wood resulted. Borate treated wood showed considerable resistance to the decay fungus compared to that of untreated control specimen.     

Influence of wood species,treatment method and biocides concentration on leaching of copper–ethanolamine preservatives

Cu–ethanolamine-based preservatives are currently the most important alternatives for classical chromated-copper formulation. However, emissions of Cu from wood impregnated with copper–ethanolamine-based preservatives are still higher compared to emissions from wood preserved with copper–chromium based preservatives. In order to elucidate leaching of copper from specimens treated (brushed, soaked or vacuum-impregnated) with different copper–ethanolamine containing biocides of two different concentrations the following research on specimens made of Norway spruce (Picea abies), Scotch pine (Pinus sylvestris) and Beech (Fagus sylvatica) were performed. The results showed that leaching is significantly affected by the wood species used. The lowest leaching rates were determined in specimens made of spruce, while the highest ones were determined in beech wood. Concentration of active ingredient influences the Cu fixation as well. Unfortunately, ethanolamine at higher concentration causes depolymerisation of lignin macromolecules, which results in increased copper leaching.     

Machining properties and surface roughness of various wood species planed in different conditions

This study was carried out to determine the planing properties and surface roughness of naturally grown Oriental beech (Fagus orientalis Lipsky.), Anatolian chestnut (Castenea sativa Mill), Black alder (Alnus glutinosa subsp. Barbata (C.A.Mey.) Yalt.), Scotch pine (Pinus sylvestris L.), and Oriental spruce (Picea orientalis (L.) Link.) grown in the eastern Black sea region of Turkey. The tests were conducted according to ASTM 1666 and DIN 4768. Test specimens were prepared from the lumber cut tangentially from logs. The machining process was carried out on a cabinet planer machine. Mainly, the effects of the rake angle and the feed speed were investigated. The cutting depth was constant with 1.6 mm. The Oriental spruce resulted in the lowest machining performance among the samples. The machining performance of the specimen increased as the feed speed or the rake angle decreased. All of the samples except the Anatolian chestnut showed lower surface roughness values. The surface roughness is found not to be affected by the feed speed, but by the rake angle. In addition, lower surface roughness values were observed for the latewood than the earlywood.     

Mechanical and chemical behavior of spruce wood modified by heat

In this study the effects of heat treatment on compression strength (CS) of spruce wood (Picea orientalis) were examined and changes in the chemical structure of the treated wood were determined by analyzing contents of cellulose, hemicellulose and lignin.

Heat treatment was applied on the test samples in an oven at four different temperatures (130, 150, 180 and 200 °C) and three different durations (2, 6 and 10 h) under atmospheric pressure.

The results indicate that the effects of heat treatment on CS values generally exhibited a decrease with increased duration and temperature. It was seen that hemicelluloses were the wood-cell components most degraded by the heat treatment.     

Bonding strength of wood materials bonded with different adhesive after aging test

In this study, it is aimed to describe the effects of adhesives (PVAc, Desmodur-VTKA and phenol formaldehyde) on Uludag fir (Abies Bornmüllerina M.) and Oriental beech (Fagus Orientalis Lipsky) cut tangentially and exposed to heating tests (40, 60, and 80 °C) and heating duration (30, 60 and 90 days) and controls. Consequently, when compared to control samples, the highest decrease of 26.2% in average with Oriental beech and 18.5% in average with Uludag fir was obtained with the samples bonded with D-VTKA adhesive kept for 90 days. At high temperatures phenol formaldehyde adhesives can be advised as the building material used for long terms.     

The effects of ply organization and loading direction on bending strength and modulus of elasticity in laminated veneer lumber (LVL) obtained from beech (Fagus orientalis L.) and lombardy poplar (Populus nigra L.)

The effects of ply organization and loading direction on bending strength and modulus of elasticity in laminated wood materials produced from 3 mm thick veneers, of beech (Fagus orientalis L.) and lombardy poplar (Populus nigra L.) placed one on top of the other in various arrangements were examined in this study. Kleiberit 303 (PVAc), a vinyl (polyvinyl acetate – PVAc) based glue was used in lamination. Eight hundred samples were prepared in order to measure oven-dry specific gravity, bending strength and modulus of elasticity values perpendicular and parallel to the glue line of a total of 10 different arrangements, eight of which have different laminated ply organizations, namely (AAAAAAA) (7A), (BBBBBBB) (7B), (ABBBBBA), (ABABABA), (AABBBAA), (AABABAA), (ABBABBA), (BABABAB), in which (A) represents beech wood and (B) represents poplar wood and the other two, which consist of solid beech and solid poplar wood in same dimensions as control samples. The samples were subjected to tests perpendicular and parallel to the glue line in accordance with the ISO 16978 standard. As a result of statistical analysis of the data obtained from the tests, the bending strength and modulus of elasticity values of solid woods both perpendicular and parallel to the glue line were observed to be smaller than those values of laminated woods made of the same species of woods. It was also observed that as contribution rate of beech in lamination increases, the bending strength and modulus of elasticity values increase.     

Abrasion resistances of cellulosic,synthetic, polyurethane,waterborne and acidhardening varnishes used woods

This study was performed to determine the abrasion resistances of some varnishes used on wood materials. For this purpose, test samples prepared from Scots pine, Oriental beech, European oak, Black poplar, Basswood and Black walnut woods, which met the requirements of ASTM D 358, were coated according to ASTM D 3023 standards with cellulosic (C), synthetic (Sn), polyurethane (Pu), waterborne (Wb) and acidhardening (Ah) varnishes. The abrasion resistance of samples after the varnishing process was determined in accordance with TS 4755. It was observed that, according to wood samples, the highest abrasion resistance was obtained in Black walnut (168.9 rpm), and the lowest abrasion resistance was obtained in Scots pine (50.63 rpm); according to varnish types, the highest abrasion resistance was obtained in acidhardening (213.4 rpm), and the lowest abrasion resistance was obtained in waterborne (45.44 rpm). In accordance with the interaction of the factors wood type, varnish type and layer type, the highest abrasion resistance was found at interaction of Black walnut + acidhardening + 3 layers (578.0 rpm), and the lowest abrasion resistance was found at interaction of Oriental beech + waterborne + 1 layer (11.50 rpm). Furthermore, it was found that interactions according to the varnish type and amount of layer thickness display differences; varnish types are efficient to the first degree and layer thickness to the second degree for abrasion resistance. In this respect, it can be stated that in wooden parquets and place floorings, in which the abrasion resistance is considerably important, the varnish application with three layers of acidhardening can provide an advantage.     

Effects of logs steaming,veneer drying and aging on the mechanical properties of laminated veneer lumber (LVL)

In this study the effects of steaming and drying condition on the mechanical properties and durability of laminated veneer lumber (LVL) and solid sawn lumber were investigated in a comparative way. Steamed beech and steamed and non-steamed spruce logs were used and two different veneer drying temperatures (20 and 110 °C) were selected for this aim. Aging test was applied according to EN 321 to determine the durability of LVL and solid wood samples. Steaming decreased considerably all investigated strength properties of LVL panels and the least affected was the compression strength. The compression strength and the static bending strength values of both beech and spruce LVL panels were higher than those of the solid wood groups obtained from the same logs. The impact strength values of LVL panels, unlike the static bending strength and the compression strength, were lower than those of the solid samples, which were not steamed and aged.     

Leaching patterns from wood of different tree species and environmental implications related to wood storage areas

Batch tests were carried out with sawdust obtained from oak (Quercus robur), maple (Acer platanoides), pine (Pinus sylvestris), beech (Fagus sylvatica) and wood chips from oak and pine. Leaching of organic compounds expressed as dissolved organic carbon (DOC) in mg/kg of dry mass took place during the first 24 h. The following additional variables were analysed: pH, conductivity, colour, phenols, tannins and lignin, and biochemical oxygen demand (BOD₇). When leachates obtained with oak wood chips and pine wood chips were compared, no significant difference was observed. However, in batch tests with sawdust, DOC released by oak (90 000 mg/kg) was significantly higher (P = 0.0001) than DOC released by pine (30 000 mg/kg). The results suggest that particle size is not the only variable affecting the leaching of organic compounds from wood. Regarding BOD, colour [platinum‐cobalt (Pt‐Co)], phenols, tannins and lignin, the leaching patterns differed among species, and oak was the species with the highest released values.     

Effect of fire retardants on internal bond strength and bond durability of structural fiberboard

This study evaluated the effect of a number of chemicals on the internal bond (IB) strength and bond durability of phenolic-bonded structural fiberboard (medium density fiberboard) panels. Borax (BX), boric acid (BA), monoammonium phosphate (MAP), diammonium phosphate (DAP), and phosphoric acid (PA) were sprayed onto the fibers made from 50% pine (Pinus nigra Arnold var. pallasiana) and 50% beech (Fagus orientalis Lipsky) woods at 2%, 4%, and 6% retention levels based on oven-dry fiber weight. The panels were tested for unaged IB strength (dry), and IB strength (aged), after cyclic-accelerated aging, according to the procedures defined by European Norm (DIN EN) 321 (1999). Unaged IB and aged IB values of all the treated specimens at three retention levels were significantly decreased when compared to untreated control values. The IB strength and bond durability of all the treated panels decreased with increasing chemical content. BX-treated specimens had the best IB strength and bond durability, followed by DAP-, MAP-, BA-, and PA-treated specimens, respectively.     

工程木梁的受弯性能试验研究

以江苏速生意杨为原材料加工的工程木材,包括层板胶合木(Glulam)和旋切板胶合木(LVL)等,提出几种新型的构件截面形式,对受弯构件的结构性能影响因素进行了详细分析。研究的主要目的是充分利用我国速生林资源,并将其应用于现代木结构建筑。首先,通过材料的材性试验,探讨了Glulam和LVL的主要物理力学性能;在此基础上,对31个工程木梁模型试件进行了弯曲性能的试验研究,分析了工程木梁的破坏形态和破坏机理,探讨了其极限承载力和抗弯刚度等弯曲性能,并对构件性能进行了对比;最后,分析了影响工程木梁结构性能的各种因素,包括层板组合方式、荷载方向、单板厚度(LVL构件)以及构件尺寸等。结果表明:工程木梁的结构性能远远超出了建筑中常用锯材梁的结构性能,其强度比樟子松锯材构件高出39.0%~90.0%,刚度高出35.0%~45.0%,若将Glulam与LVL进行优化组合,会取得更好的效果;构件横截面平均应变基本上呈线性分布,构件的极限拉应变约为0.006,而其破坏时的压应变最大为0.009左右;     

Technological and economic comparison of the usage of beech and alder wood in plywood and laminated veneer lumber manufacturing

In this study, the economic and technological benefits of the usage of alder wood instead of beech wood as a raw material in plywood and laminated veneer lumber (LVL) manufacturing were compared, besides the conservation of national forest resources. For this aim, some technological properties of plywood and LVL panels manufactured from beech and alder logs were determined, and then compared with the values indicated in related standards. According to the results of this study, mechanical strength values of beech plywood and LVL panels were higher than those of alder panels. Bending strength mean values of plywood panels were higher than the limit values indicated in DIN 68705-3 and DIN 68792. Shear strength mean values obtained for the plywood panels manufactured from alder logs were above the limit value (1.0 N/mm²) indicated in EN 314-2 standard. Mechanical strength values of beech LVL panels were also higher than those of alder LVL panels. When the annual increments of beech and alder trees in 1 ha and the time they need to reach suitable diameters for the manufacturing rotary cut veneers were taken into consideration, it was calculated that alder trees allow 3.82 times additional physical harvesting than beech trees.     

Influences of some factors on the formaldehyde content of particleboard

In this study, effects of specific gravity (SG), shelling ratio, wood species, and pressure on the formaldehyde content, physical (SG and thickness swelling (TS)), and mechanical properties (modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond (IB) strength) of particleboard were examined. The best manufacturing parameters were determined for E₁ grade particleboard manufacturing from urea formaldehyde (UF) adhesive. Based on the findings of this study, increasing of SG, shelling ratio, and pressure increased the formaldehyde content. Particleboard made from particles consisting higher amount of beech particles had lower formaldehyde content than that of panel from particles consisting higher amount of pine particles.     

Water vapor sorption isotherm modeling of commercial oriented strand panel based on species groups and resin type

The moisture sorption response of commercial OSB panels at room temperature were examined as a function of humidity. The OSB panels were pine OSB—southern pine (Pinus spp.) mixed with 10–20% of hardwood, usually maple (Acer spp.); aspen OSB—nearly 100% aspen (Populas tremuloides Michx.); and, poplar OSB—40% yellow-poplar (Liriodendron tulipifera L.), 20% maple (Acer spp.), 10% pine and 30% unknown mixture. Two panels from each species group of OSB were chosen based on resin of phenol formaldehyde (PF) face and methyl di-isocyanate core or PF face and PF core. The multi-step sorption isotherm was modeled with the GAB isotherm model and the A/D ratio was determined from the data. Using the model, it was found that the heats of sorption were 6–8 times increased in OSB compared to solid wood. Also, based on the model analysis, the unimolecular layer was smaller compared to solid wood. The average A/D ratio, which is related to the hysteresis, was smaller compared to solid wood.     

Untersuchungen zum Verhalten von mit Nanopartikeln imprägniertem Holz bei Freibewitterung

Es wurde die Witterungsbeständigkeit von Fichtenholz und Buchen holz nach Beschichtung mit verschiedenen nanoskaligen Hydrophobierungsmitteln und vergleichsweise dazu mit einem üblichen Lack getestet. Die Imprägnierung des Holzes erfolgte über Streich‐ oder Druckimprägnierung. Erfasst wurden Änderungen der Farbkennwerte, der Benetzungswinkel, der Holzfeuchte sowie der visuelle Gesamteindruck. Bei allen Materialien und Beschichtungs arten trat bereits nach kurzer Zeit eine Vergrauung auf. Diese war beim Standardlack am geringsten. Diese Tendenz spiegeln auch die Farbmessungen wieder. Der Benetzungsrandwinkel reduzierte sich zunehmend, das zeigt, dass der Hydrophobierungseffekt nach lässt. Beim Standardlack war der Effekt deutlich geringer ausgeprägt. Insgesamt zeigt sich, dass es weder mit Streich‐ noch mit Druckimprägnierung gelang, das Imprägnierungsmittel ausreichend tief in das Holz einzubringen und zu fixieren. Dies deckt sich mit den Ergebnissen der Flüssigkeitsaufnahmekoeffizienten, über die in vorangegangenen Arbeiten berichtet wurde. Investigation regarding the behaviour of wood impregnated with nano‐particles and exposed to the open weather. The weather resistance of Norway spruce and beech wood has been tested following coating with various nano‐scale hydrophobising compounds, and has been compared with reference samples that were coated with a standard varnish. The impregnation of the timber was carried out by brush coating or a pressure process. The test results focused on changes in colorimetric values, wetting angle, timber moisture and the overall appearance. All materials and types of coating were subject to a greying of colour after a short while. The standard varnish showed the least discoloration. This tendency was also reflected in the colorimetric measurements. The wetting edge angle increasingly reduced, indicating that the hydrophobising effect was also reducing. With the standard varnish, this effect was clearly less pronounced. Overall, the tests showed that it had not been possible to inject the timber sufficiently deeply with the impregnation compound, and fix it, with either the brush or pressure impregnation method. This confirms the findings obtained in fluid retention co‐efficient tests which were reported in previous articles.     

Influence of temperature on fixation of copper–ethanolamine-based wood preservatives

Market share of copper–ethanolamine-based wood preservatives is increasing in the past decade; despite of the fact that copper fixation is still not comparable to fixation of copper–chromium-based ones. One of the reasons for increased emissions originates in ethanolamine. Ethanolamine excesses depolymerizes lignin macromolecule, what consequence in higher leaching rates. In order to eliminate this negative influence of ethanolamine, Norway spruce wood blocks were impregnated with three different copper–ethanolamine solutions of three concentrations. After impregnation, specimens were dried at four different temperatures (25, 50, 75 and 103 °C) and, afterwards, leached according to the modified ENV 1250 procedure. The results showed that increased temperatures during fixation did not decrease but increased copper leaching. It is presumed that the main reason for observed fact is ethanolamine, which did not evaporate from wood. Unfortunately, increased temperatures dramatically increase lignin depolymerization, as well as copper leaching.