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The physical and mechanical properties of particleboard panels were evaluated relative to various loading levels of nanocellulose (NC) and boric acid (BA) in the urea-formaldehyde (UF) resin used for panel production. The results showed that NC and BA reinforcement substantially affected the performance properties of the particleboard panels. It was determined that using 3% NC and 3% BA in the panels afforded the best results relative to thickness swelling (TS), water absorption (WA), moisture content (MC), modulus of rupture (MOR), modulus of elasticity (MOE), and internal bonding strength (IB). It was concluded that the performance properties of the particleboard panels could be enhanced by adjusting the loading levels of NC and BA. The study also showed that it is possible to apply NC and BA as modifiers for the formaldehyde resin in the process of manufacturing particleboard panels. The NC and BA reinforcement techniques could be used to develop novel furniture components and interior design materials. Istanbul University-Cerrahpasa Research Fund [31076]; Turkish Academy of SciencesTurkish Academy of Sciences; [4806]; [19515]; [31014]; [43150]; [49525] The authors would like to thank Istanbul University-Cerrahpasa Research Fund for its financial support in this study (Project No. 31076). Additionally, the support from Project Nos. 4806, 19515, 31014, 43150, and 49525 is greatly acknowledged. The authors thank Kastamonu Integrated Wood Industry and Trade Inc., Gebze, Turkey for providing raw materials, and Starwood Forest Products Inc., Bursa, Turkey for testing facilities. The support from Turkish Academy of Sciences is also appreciated.

WOS: 000540457600076 Effects of the wood species, number of teeth, and adhesive type were studied relative to the moment capacities of box joints under tension and compression loadings, which is commonly used in case type solid wood furniture. For this purpose, L-type specimens were prepared from Scotch pine (Pinus sylvestris L.), poplar (Populus sp.), and fir (Abies sp.). Polyvinyl acetate (PVAc) and polyurethane (PU) adhesives were used in the preparation of joints. Tension and compression tests with 360 samples were performed under static loading. According to the results, the highest moment capacities were obtained for Scotch pine under tension, and poplar specimens under compression. With respect to the number of teeth, the highest moment capacities were obtained with 12-tooth joints under both tension and compression loadings. For adhesive types, the specimens glued with PVAc gave better results in both tension and compression. In manufacturing of solid wood based case-type furniture, the higher number of teeth resulted in a slightly better performance; however, the results with the 4-tooth structure was not too far from 8-tooth. Furthermore, it was concluded that Scotch pine as a substance and PVAc as adhesive could be recommended.

Ayrilmis, Nadir/0000-0002-9991-4800 WOS:000511129100105 Use of electrostatic powder coating technology for wood-based panels has considerably increased in the last decade. In this study, oriented strand boards (OSB; OSB/2 and OSB/3 grades) were coated with powder coatings using an electrostatic corona spray gun. Epoxy/polyester (hybrid:1/1) coating that is suitable for indoor applications was applied to the surface of OSB specimens (150 g/m(2)) at three different curing temperatures, 120 degrees C for 15 min, 140 degrees C for 10 min, and 160 degrees C for 10 min using the electrostatic corona gun. The surface properties of the OSB specimens, roughness, wettability, scratch resistance, abrasion resistance, and film thickness were determined. The abrasion resistance and scratch resistance of the coated OSB specimens improved with increasing curing temperature from 120 to 160 degrees C. The highest mechanical surface strength was obtained from the OSB/3 specimens cured in the infrared oven at 160 degrees C for 10 min, while the lowest strength was found in the OSB/2 specimens cured in the infrared oven at 120 degrees C for 15 min. The contact angle values of the coated OSB specimens increased with increasing curing time, while the surface roughness decreased. The curing temperature of the electrostatic powder coating may be a useful indicator to users to obtain better surface quality on the substrate.

A method for producing lignocellulosic fibrillar fines directly from moist wood through a grinding process was evaluated. The method is based on a conventional stone wood grinding process with a novel grinding stone surface structure. The grinding stone (wheel) with a surface profile serrated in the axial direction of the wheel, forces fibres to break down into fibrils instead of detaching as fibres from the wood matrix. The arrangement mimics the inclined feeding of a log against a grinding stone and is completed without any related technical difficulties. Typically over a 90% conversion rate to fines (passing the Standard Mesh 200 wire) were achieved. The characteristics of the fines were influenced by the details of the surface structures, the velocity of the grinding stones, the feeding rate of the woods, and the specific energy consumption. This method enables novel means to adjusting the structure and properties of paper and paperboard products, as well as those of novel fibre and fibre-composite products.

This study explored the potential of natural light to enhance wooden interior environments. Under Nordic light, natural materials such as wood finishes present an opportunity to create warm, bright, and pleasant atmospheres, enhancing psychological well-being and comfort. The objectives of this project were twofold: first, to study the diversity of northern sky conditions in terms of cloud cover and thickness, and, second, to evaluate the impacts of the diversity of natural light on five wooden scale models. The methodology involved weather data collection that took place during the spring equinox in Quebec City. In order to create a cloudiness scale, sky condition data and photometric measurements were collected. A photographic survey occurred in five scale models made with interior wooden finishes of varying color combinations, documenting the impact of sky diversity on brightness, hue, and contrast. Simultaneous scale model studies under a real sky allowed direct comparison under the same lighting conditions. There was a remarkable diversity of visual ambiences for a southeast-oriented space depending on the position of the sun and sky conditions. Gray-dyed wooden finishes created dull and unchanging atmospheres, while yellow oaked surfaces allowed various dynamic ambiences.

Many environmental advantages of wood in buildings have been thoroughly documented; however, this material’s effects on occupants are not well known or fully comprehended. This research aims to study comfort parameters in a multifunctional room characterised by extensive wood surfaces in comparison with a similar room with more conventional surfaces at Laval University, Quebec, Canada. The objectives of this research focus on determining the thermal, visual, and acoustical similarities and differences between two rooms using on-site surveys. Analysis of instrumental measurements and images of each room’s indoor environment under overcast skies determined the colour and texture of the surfaces. Quantitative and qualitative analyses revealed that both rooms share similar thermal and acoustic comfort parameters, but have contrasting visual characteristics. The colour, knots, and grain of the wood contributed to producing visually warm experiences resulting in a yellowish room, whereas a mix and match of artificial finishes generates a colder, bluish ambiance in the other room. The conclusion suggests that architects and designers should consider the indoor use of wood for its unique visual ambiances that enhance comfort levels.

Wood that is used in outdoor applications is frequently exposed to weathering and is thus prone to fungal degradation. Ways to prevent fungal degradation include keeping the wood dry. The majority of hydrophobic and wood modification systems have been tested only on freshly treated wood. Little information is available on how various wood-based materials perform after a certain period of weathering. To elucidate this question, 17 wood samples were tested from the following species: oak (Quercus), sweet chestnut (Castanea sativa), European larch (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris), Norway spruce (Picea abies), and beech (Fagus sylvatica). Moisture performance of the wood samples was improved with thermal modification, wax, oil, and biocide treatment. Specimens were exposed to various degradation-aging factors (blue stain fungi, decay fungi, artificial weathering, and natural weathering). Various moisture performance tests were applied before and after aging: short-term water uptake (tensiometer), long-term water uptake, water vapor tests, drying tests, etc. The water exclusion efficacy of wood was decreased after aging. Aging factors were found to act synergistically and to have a more prominent influence on less durable wood compared to durable or preservative-treated wood. Wax-treated wood performed best, regardless of which moisture performance test was applied.

A new deformation technique of wood flow forming is promising for industrial uses of solid wood. Flow deformability, size stability, and good mechanical properties were obtained by using wood impregnated with low molecular weight phenol formaldehyde (PF) resin. In this study, to clarify the effect of the PF resin and moisture contents in wood on the flow deformability (extrudability) and the mechanical properties of the product (extrudate), a lateral extrusion was conducted by using wood impregnated with various contents of PF resin and three levels of moisture content. The results indicated that the extrudability of wood impregnated with PF resin improved with an increase in both PF resin and moisture content. The mechanical properties of the extrudate worsened with increases in the moisture content of the wood impregnated with PF resin. Because most of the water in the wood remained in the mold during the extrusion process, chemical changes of the wood substance and PF resin occurred due to steam forming under the high temperature and pressure of the extrusion. The steam worsened the mechanical properties of the extrudate.

The crystallinity and acoustic-vibration parameters of Picea jezoensis, including specific Young’s modulus (E/ρ),coefficient of sound-radiation resistance (R), sound resistance (ω), and the ratio of Young’s modulus to the dynamic stiffness modulus (E/G), before and after heat treatment were measured and characterized. Conditions for the heat treatment included N2 as the protection gas and temperatures of 170 °C, 190 °C, and 210 °C with holding times of 2 h, 3 h, and 4 h. The results showed that specific Young’s modulus, the coefficient of sound-radiation resistance, and the ratio of Young’s modulus to the dynamic stiffness modulus increased, whereas sound resistance decreased, thereby improving the acoustic performance of the wood. The maximum increments were 5.7% for specific Young’s modulus (210 °C, 3 h), 8.8% for the coefficient of sound-radiation resistance (210 °C, 3 h), and 13.8% for the ratio of Young’s modulus to the dynamic stiffness modulus (210 °C, 4 h). Conversely, the maximum decrease in sound resistance was 5.6% (170 °C, 2 h). The crystallinity of heat-treated samples universally increased, and the maximum reached 60.67% (210 °C, 4 h), which was 9.9% higher than that of the control group. Moreover, the sound resistance decreased within increasing crystallinity growth, indicating that these two parameters were negatively correlated. Overall, the acoustic-vibration performance of P. jezoensis was improved through heat treatment, with the best vibration performance obtained at 210 °C with a holding time of 4 h.

Water plays a very important role in wood and wood products. The molecular motion of water in wood is susceptible to thermal activation. Thermal energy makes water molecules more active and weakens the force between water and wood; therefore, the water molecules dynamic properties are greatly influenced. Molecular dynamics study is important for wood drying; this paper therefore focuses on water molecular dynamics in wood through fast field cycling nuclear magnetic resonance relaxometry techniques. The results show that the spin-lattice relaxation rate decreases with the Larmor frequency. Nuclear magnetic resonance dispersion profiles at different temperatures could separate the relaxation contribution of water in bigger pores and smaller pores. The T1 distribution from wide to narrow at 10 MHz Larmor frequency reflects the shrinkage of pore size with the higher temperature. The dependence of spin-lattice relaxation rate on correlation time for water molecular motion based on BPP (proposed by Bloembergen, Purcell, and Pound) theory shows that water correlation time increases with higher temperature, and its activation energy, calculated using the Arrhenius transformation equation, is 9.06±0.53 kJ/mol.

Woody tissues consist primarily of a mixture of cellulose, hemicelluloses, and lignin. Covalent bonds between lignin and polysaccharides likely play a central role in determining the mechanical and physical properties of wood. Intact and defined lignin-polysaccharide networks have not been isolated in large quantities because of the recalcitrance of lignin, which demands harsh chemical treatments that alter its structure. This report presents a method for preparing large quantities of lignin-polysaccharide networks similar to those naturally present in wood based on the enzymatic oxidation of hemicellulose from Norway spruce. Fungal enzymes produced from various carbon sources were used to depolymerize these networks. The method was used for simulating "enzyme mining" - a concept in biorefineries, giving a possible explanation for its mechanisms. QC 20160223

Spruce and beech samples were irradiated by UV light in humid (100% air humidity) and dry conditions to clarify the effects of vapor on photodegradation. UV-irradiated samples were also soaked in distilled water for comparison. The color change and the IR absorption spectra were measured. The wet condition generated considerably greater discoloration than did the dry condition. The intensity of the color change was higher at elevated temperature (53 °C) than at 32 °C. The results showed that the presence of water as vapor increased the degradation of lignin. The nonconjugated carbonyl groups absorbing around 1760 cm-1 were found not to be stable, and the number of these chemical groups decreased in the presence of vapor when compared against the dry condition. The rising temperature amplified this degradation effect.

Methylated fatty acid (FA) compounds in the heartwood and bark of some softwood species, specifically Pinus sylvestris, Abies alba, Picea abies, and Larix decidua, grown in the Czech Republic were evaluated. Strong H2SO4 was used for methylation of the lipids. The highest content of lipid was found in P. abies bark (40.132 mg/g o.d. sample), and the lowest content was in A. alba wood (11.027 mg/g o.d. sample). The highest concentration of FAs was observed in L. decidua bark. The highest percentages of FAs in wood of P. sylvestris were arachidic acid and oleic acid. In bark, the highest percentages of FAs were stearic acid, palmitic acid, and oleic acid. The FAs with the highest concentrations in A. alba wood were arachidic acid, palmitic acid, pentadecanoic acid, and margarinic, and those in bark were behenic acid, lignoceric acid, and arachidic acid. P. abies wood FAs showed arachidic acid, palmitic acid, and margarinic acid, and the bark contained lignoceric acid and arachidic acid. The FAs of L. decidua wood were arachidic acid, palmitic acid, and stearic acid, and in bark they were pentacosylic acid, docosahexaenoic acid (DHA), lignoceric acid, arachidic acid, and behenic acid. The lack of typically dominant unsaturated fatty acids (e.g. 18:1, 18:2), compared to literature values were attributed to the application of strong acid for the hydrolysis.

Wood and bark oil extractives components (OECs) of Pinus sylvestris, Abies alba, Picea abies, and Larix decidua grown in the Czech Republic were analyzed using gas chromatography/ mass spectrometry (GC/MS). The analysis showed the presence of monoterpene, sesquiterpene, diterpenoids, and resin acids. The highest percentages of OECs in the wood of P. sylvestris were α-fenchyl alcohol (26.04%), D-fenchyl alcohol (12.39%), and L-borneol (8.81%); the OECs in the bark included α-methyl-γ-butyrolactone (31.88%) and isodecyl octyl phthalate (15.85%). The most frequently occurring OEC in A. alba wood were 4-hydroxy-4-methyl-2-pentanone (73.36%), α-cedrol (10.08%), and 2,6-dimethyl-1,3,6-heptatriene (7.35%); the most OECs in the bark were di(2-ethylhexyl)phthalate (59.83%), methyl cyclopentane (16.63%), and 13-epimanool (6.31%). P. abies wood OECs included 4-hydroxy-4-methyl-2-pentanone (29.42%), α-cedrol (26.98%), ∆3-carene (6.08%), and terpinen-4-ol (5.42%); the most OECs in the bark were di(2-ethylhexyl)phthalate (30.91%), cyclohexane (12.89%), caryophyllene oxide (8.90%), and α-pinene (4.59%). OECs of L. decidua wood were α-terpineol (26.06%), isoborneol (14.12%), camphene (11.78%), D-fenchyl alcohol (10.39%), and larixol (4.85%); OECs in the bark were larixol (33.29%), phthalic acid mono-2-ethylhexyl ester (16.96%), 13-epimanool (15.40%), and cyclohexane (8.44%).

Contact angle methods are widely used to evaluate the wettability of cellulose-based surfaces and to judge their suitability for different applications. Wettability affects ink receptivity, coating, absorbency, adhesion, and frictional properties. There has been a continuing quest on the part of researchers to quantify the thermodynamic work of adhesion between cellulosic surfaces and various probe liquids and to account for such components of force as the London/van der Waals dispersion force, hydrogen bonding, and acid and base interactions. However, due in part to the rough, porous, and water-swellable nature of cellulosic materials, poor fits between various theories and contact angle data have been observed. Such problems are compounded by inherent weaknesses and challenges of the theoretical approaches that have been employed up to this point. It appears that insufficient consideration has been given to the challenging nature of cellulosic materials from the perspective of attempting to gain accurate information about different contributions to surface free energy. Strong hysteresis effects, with large differences between advancing and receding contact angles, have been overlooked by many researchers in attempting to quantify the work of adhesion. Experimental and conceptual approaches are suggested as potential ways to achieve more reliable and useful results in future wettability studies of cellulosic surfaces.

The surface roughness of Chinese fir and Eucalyptus wood samples were measured using the stylus profile method in order to investigate the correlation between near infrared (NIR) spectroscopy and surface roughness. The results showed that the NIR spectra absorption showed differences among samples from different surface roughnesses, and the absorption decreased with the increase of the surface roughness. A strong relationship was found between the surface roughness parameters, i.e., the arithmetical mean deviation of the profile (Ra), the ten-point height of irregularities (Rz), and the maximum height of profile (Ry). Based on the NIR spectra of the Chinese fir wood samples and the mixed wood samples of the two wood species, and the correlation coefficients of these two types of wood samples in a calibration set were 0.77 to 0.83 and 0.67 to 0.74, respectively. A relatively poor correlation was found in the model based on the Eucalyptus samples; however, it was still significant. These results suggested that there was relative information about the surface roughness from the NIR spectra, which further illustrated that the surface roughness may influence the effect of models for wood properties built by NIR data.

The effects of seasoning on resistance of sapwood and heartwood of Dalbergia sissoo Roxb., Acacia nilotica Wild., and Pinus wallichiana A. B. Jacks against consumption by Odontotermes obesus (Ramb.) was evaluated in no-choice and choice laboratory and field experiments. Seasoning was done in an oven at 60, 80, and 100 °C for 10 and 15 days. The amount of wood consumed generally decreased as the drying temperature increased, indicating that the drying process contributed to termites’ resistance of the woods and made them unpalatable for the termites. The woods that were dried at 100 °C for 15 days showed a significant reduction in weight after the consumption by termites compared to the woods dried at 60 and 80 °C and control both in laboratory and field trials. Similarly, the wood that was dried at 100 °C for 15 days showed highest termite mortality rate in laboratory no choice and choice tests. Consequently, the termites showed maximum feeding propensity on unseasoned P. wallichiana and the minimum on seasoned D. sissoo measured with significant differences in weight loss and mortality. Based on the feeding indicated by wood weight loss, the descending order of preference was Dalbergia sissoo > Acacia nilotica > Pinus wallichiana. The importance of wood seasoning for termites’ resistance is also discussed.

The purpose of this study was to evaluate the effects of an industrial heat treatment (ThermoWood) based on changes in the strength properties, density, and color of spruce (Picea abies) and pine (Pinus sylvestris) woods. Samples were subjected to heat treatment processes at 212 °C for a duration of 120 min. The results showed that the applied process caused a 2.56 to 6.12% decrease in density. Dimensional stability was considerably improved, with ASE values of 58% and 52% for spruce and pine, respectively. The color became darker after treatment. The process caused a significant (p

There are different dynamic or static test methodologies for evaluating the shear and torsional moduli of wood. A preferred method is nondestructive, accurate, and standard. However, dynamic methods using conventional devices previously suggested for determining the orthotropic shear moduli of wood are neither accurate nor standard. Thus, a reliable method for evaluating the torsional modulus of wood through a torsional vibration test exists; however, it is not a standard test method at all. In this study, a standard methodology for refractory materials, ASTM C1548, was fitted to wood to meet the qualifications suggested in measuring the torsional vibration of an orthotropic material. A methodology based on Timoshenko’s advanced theory of free flexural vibration for orthotropic shear moduli was also defined to be compared to these reliable, standard procedures of torsional modulus evaluation. A promising conclusion was derived using improved computer-based instrumentation.

The objective of this study was to assess the influence of varying temperature on the strength characteristics of joints bonded using three types of one-component PVAc adhesives (i.e., Rakoll Express D3, Titebond II Premium, and Rhenocoll 3W, 4B Plus) that belong to the group of thermoplastic wood adhesives intended for non-construction bonding applications. The measuring procedure was a transverse tensile test for estimation of joint strength. As documented by the test results, a higher joint strength achieved at a higher temperature was achieved again after a gradual increase in the joint temperature from 20 °C to 140 °C and subsequent cooling to the starting temperature. After cooling the joint to the starting temperature, all tested adhesives complied with the minimum strength, namely 10 MPa. The results obtained in this study indicated that the resistance and thus the strength of joints bonded using contemporary PVAc adhesives increases with time.

It is preferred to perform conformity assessment of wood-based panels on the whole panel without cutting it down to smaller pieces. The modulus of elasticity, a mechanical property of wood, was determined by longitudinal vibration testing with the full-size panel, and the results were compared with results of tests of prismatic beams. The Brancheriau’s correction coefficient was used to compensate for errors from cross-sectional dimension variations and errors from Poisson’s ratio. Longitudinal excitation of the panels along the length was shown to be successful in evaluating the modulus of elasticity. However, strong correlations obtained from plate and beam comparisons along the width of the panels are promising.

The 3D-moldability of veneers, as opposed to the moldability of plastic or other materials, is limited because of the characteristics of wood. Veneers can be modified by physical, chemical, or mechanical treatment. We chose water and ammonia-water solutions. After treatment for an established time, the moldability of veneers was examined. The level of concave deflection of a test piece of punch-molded veneer was assessed. Three sets of test pieces were tested by dipping in cold water (20 °C), hot water (95 °C), or a 25% solution of ammonia, for different durations of time. The results showed that the 3D-moldability of veneers increased by 66 to 119% after plasticization by a 25% solution of ammonia, unlike the unmodified veneers with a moisture content of 7.65%. The increase in moldability was significantly higher in comparison to the veneers modified by dipping in cold water (20 °C) and hot water (95 °C). Futhermore, the relationship between the moisture content of the veneers after their modification/plasticization, the level of concave deflection, and the molding force in relation to the level of concave deflection were examined.

The objective of this work was to evaluate the effect of the addition of bamboo laminas of the species Dendrocalamus giganteus to three-layer medium density particleboard (MDP). These laminas were glued onto both the top and the bottom of each panel. With the manufactured panels laminated with bamboo, mechanical tests based on the Brazilian Standard ABNT NBR 14810 were carried out to determine the modulus of rupture (MOR) in static bending and the tensile strength parallel-to-surface. These mechanical tests were realized in particleboards of eucalyptus and in reinforced particleboard, both produced in the laboratory. The modulus of rupture and tensile strength parallel-to-surface of the laminated MDP had values close to those that have been reported. The reinforcements increased the values of these studied properties. Nevertheless, this fact indicated the possibility to produce a stronger MDP using bamboo lamina as surface layers. These results show the possibility of using coated-bamboo MDP for utilization in large spans, for example, in flooring for mezzanines with finish on both sides, and for robust furniture as bookshelves, beds, tables, etc.

There are different reasons for planing timber. One is to adjust the cross-sectional dimensions of thickness and width. Another is to adjust the timber's outer shape, usually in order to reduce warp resulting from drying and having the forms of cup, twist, bow, and crook. The end-result depends on the properties of the timber before planing and on the planer design and settings. In the present work it was found that increasing or decreasing the forces exerted on the timber by a four-sided planer does not affect the cutting depth or the twist reduction. The pressure settings do not affect the rectangularity or the amount of unplaned areas on the surfaces either. The possibility to impact the result with this type of planer, apart from the cutting depth and planed dimensions, is slim to none.

The aims of this study were to introduce a new laboratory microwave device developed for the modification of wood properties and to examine the effect of microwave radiation on moisture loss, surface temperature, and mechanical properties (the static modulus of elasticity - MOE, and the modulus of rupture - MOR) of Norway spruce (Picea abies). The device was developed for a continuous modification process. The microwave (MW) generator works at a frequency of 2450 MHz, and the adjusted output ranges from 0.6 to 6 kW. The experiment was based on four different modes of MW modification, each of them with a varied generator output and conveyor speed. Regarding mechanical properties, the results showed that a feasible output for the MW modification of the samples was up to 3 kW, with a conveyor speed of around 0.4 m/min. The greatest moisture loss, approximately 40%, was found in the group treated at 5 kW and 0.2 m/min. The highest surface temperature, 87 °C, was measured in the group treated at 5 kW and 0.4 m/min after the second passage through the modification chamber.

Wood easily acquires a large amount of moisture when it is exposed to high-humidity conditions. The high moisture content influences the service life of wood. Thus, there is a need for an accurate, rapid, nondestructive, and simple measurement technique for wood’s moisture content. This investigation proposes a method to measure the moisture content of wood by the wood volumetric heat capacity using a transient hot wire (THW) technique. The moisture content was inferred from the change of the volumetric heat capacity before and after the wood acquired moisture; the volumetric heat capacity is the ratio of the thermal conductivity to the thermal diffusivity. The results were validated by the gravimetric method, displaying good agreement, with discrepancies within 4%.

Green fir wood (Pseudotsuga menziesii) was modified with polyethylene glycol (PEG) to produce wood composites for energy storage and conversion. The PEG-modified wood composites were evaluated based on their dimensional stability, durability, and thermal properties by various analytical methods. The differential scanning calorimetry (DSC) results showed the melting temperature and the latent heat of the phase change material (PCM) composite were 26.74 °C and 73.59 J/g, respectively. Thermal cycling tests and thermogravimetric analysis confirmed the composite exhibited good thermal stability, reliability, and chemical stability. All treated specimens were free from noticeable defects, and the addition of a surface varnish coating prevented PEG from leaching. The PEG-modified composites exhibited improved dimensional and thermal performance, which makes this material a potential candidate for economical and green, lightweight building materials.

Korkmaz, Mustafa/0000-0001-5595-2154 WOS: 000384922400166 This study investigated the effects of densification and heat post-treatment on the Janka hardness and microscopic structure of relatively low-density Uludag fir, linden, and black poplar woods. Wood samples were densified with compression ratios of 25% and 50% at 100 degrees C and 140 degrees C, respectively. Heat post-treatment was then applied to the samples at 185 degrees C and 212 degrees C for 2 h. The hardness in the radial and tangential directions was determined, and morphological changes in the cell structures were analyzed using scanning electron microscopy (SEM). The hardness values in the radial and tangential directions of the densified samples increased depending on the compression rate and treatment temperature. The hardness values in both directions were higher in the 50% compressed samples. For samples compressed at 140 degrees C, the hardness values were higher in the tangential direction, whereas the samples compressed at 100 degrees C were higher in the radial direction. After the heat post-treatment process, the hardness values of all samples decreased. As the treatment temperature increased, more adverse effects on the hardness was noted. According to the SEM analyses, the densification and heat post-treatment deteriorated the cell structure of the samples. The more cell deformation was observed in the samples densified at 100 degrees C with compression ratio 50% and high heat post-treatment temperature. Research Fund of Duzce UniversityDuzce University [BAP-2013.07.01.174] The authors are grateful for the support of the Research Fund of Duzce University, Grant. No. BAP-2013.07.01.174.

Laminated wood veneer lumber intercalated with rubber sheets (LLVR) was fabricated using a layered adhesive system composed of polyaryl polymethylene isocyanate (PAPI) for wood-rubber inter-bonding and phenol formaldehyde (PF) resin to glue the wood veneers. The optimized manufacturing process (chloroprene rubber: CR; PAPI: 80 g/m2; PF: 200 g/m2; and silane: 9.0 wt.%) was determined. The process as developed was then utilized to fabricate nine-ply LLVRs of five balanced constructions with two or three CR laminates used as various layers. The physico-mechanical properties of the LLVRs were evaluated, and the results showed that LLVRs had strong shear strength, sound dimensional stability, decent bending strength, and favorable toughening and buffering performances. The newly developed product is an interesting potential alternative to traditional laminated veneer lumber or plywood.

Mechanical properties of wood were evaluated using nondestructive test methods. The tests were conducted using the stress wave timing and resistance drilling machine, while static mechanical tests were conducted by an Instron universal testing machine. Both nondestructive and static mechanical tests were performed on wood specimens for Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) and elm (Ulmus rubra). There were strong linear correlations between density (ρ) and resistance amplitude (F), static modulus of elasticity (MOE) and dynamic modulus of elasticity (ED), modulus of rupture (MOR) and ED, and ultimate compressive strength (UCS) and ED. Additionally, an algorithm of the reliability index was developed with the first-order second-moment method. The reliability analysis indicated that the reliability index increased with the decreased design value for both Chinese fir and elm, but it increased as the live-to-dead load ratio (ρ) increased. To achieve the reliability index requirements of the Chinese national code, the MOR design value should be set to 12.6 and 21.7 MPa, while the UCS design value should be set to 10.2 and 13.4 MPa for Chinese fir and elm, respectively.

The use of wood in outdoor, above-ground applications is increasing in Europe. To further increase wood usage, more information related to service life and maintenance costs must be provided. Water exclusion efficacy (WEE) is one of the most important factors influencing service life and strongly correlates to wood moisture dynamics, surface properties, and hydrophobicity (WEE as a whole). WEE can be improved with modifications and hydrophobic treatments. The aim of this study was to elucidate which wood surface properties affect WEE and to note changes over time caused by artificial or natural aging. Wood samples of oak (Quercus), sweet chestnut (Castanea sativa), European larch (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris), Norway spruce (Picea abies), and beech (Fagus sylvatica) were used to investigate this phenomenon. The moisture performance of the wood samples was improved with thermal modification, wax, oil, and biocide treatment. In total, 17 materials were prepared. After treatment, four different aging procedures were applied. Before and after aging, Fourier transform infrared spectra, colour, and contact angle were determined. The analysis of untreated wood based materials indicated that durability and hydrophobicity are related. Of all the treatments, wax performed the best and retained high hydrophobicity even after the most severe aging method (outdoor exposure).

This paper utilized 12 coating systems, based on an acrylate and a hydrophobic polymer, with the addition of light pigments, nano-sized polyvalent metal (AsS-chelate complex) for ultraviolet protection, and iodopropynyl butylcarbamate fungicide. This study deals with the impact of the number of coats on the color stability and the surface defects of painted black locust (Robinia pseudoacacia L.) and Norway spruce (Picea abies Karst L.) woods after up to three years of natural weathering, at a slope of 45°. The best coating system was created from three coats, which consisted of two pigmented acrylates (PerlColor) and one transparent hydrophobic water-repellent (AquaStop). The total color change, ΔE*, of the weathered surfaces was approximately two times lower when the application involved a pigmented coating system compared with a transparent one. The color stability of the surfaces and their resistance to defects was better when the coating system was applied to black locust wood compared with spruce wood. Smoother surfaces of wood before painting resulted in a higher resistance against cracking and other defects caused by natural weathering; however, the effect of the initial wood roughness on the color stability of painted woods during natural weathering was usually negligible.

The heat of combustion relative to the mass, Qm, was evaluated for 13 deciduous wood species, ranging from low to high density. The maximum and minimum values for Qm ranged, respectively, from 19.01 kJ⋅g-1 (Sd = 7 J⋅g-1) to 21.66 kJ⋅g-1 (Sd = 6 J⋅g-1) for Populus tremula and Alnus glutinosa wood. The average value of the Qm for all wood specimens evaluated in the present study was 19.93 kJ⋅g-1 (Sd = 706 J⋅g-1), which is 1.6% higher than the value reported in the literature (Krzysik 1975). A high correlation, R = 0.99, was observed between the volumetric heat of combustion, Qv, and wood density, D0. No correlation was discovered among Qm, D0, the ash content in the wood, ac, as well as the content of the following elements in the ash: calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), silica (Si), aluminum (Al), iron (Fe), copper (Cu), manganese (Mn), sulfur (S), and phosphorus (P).

To test the hypothesis that wood coated with rutile TiO2 nanostructures can undergo degradation because of the photocatalytic activity of TiO2, three sets of wood specimens were aged at an accelerated rate. These three sets consisted of blank wood (BW), HDTMOS/MTMOS-coated wood (WHM), and TiO2/HDTMOS/MTMOS-coated wood (WTHM). After exposure to 155-h UV irradiation, the wettability of WTHM changed from hydrophobic to hydrophilic. This indicated that the initial low-surface free-energy materials underwent degradation because of the photocatalytic activity of TiO2. After exposure to 960 h of UV light irradiation and water spray, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA) of WTHM showed that rutile TiO2 nanostructures had partially peeled off the wood surface. This suggested that the adjacent wood surface also suffered degradation because of the photocatalytic activity of TiO2. Although the rutile TiO2 coating noticeably enhanced the color stability during UV light aging, it made a relatively small contribution to the color stability of the wood during UV light and water spray weathering process. This study suggests that to derive the greatest benefit from modification of wood surfaces with rutile TiO2 nanostructures for weathering resistance, it is necessary to take measures to inhibit the photocatalytic activity of TiO2 or to fix the TiO2 coating on the wood surface.

Treating wood with impregnating materials in order to improve resistance to burning is a commonly employed safety measure. In this study, chestnut (Castanea sativa Mill.) wood samples were impregnated using either Tanalith-E or Wolmanit-CB according to ASTM-D 1413-76 and surface-treated using water-based or synthetic varnish according to ASTM-D 3023. These samples were used to investigate the combustion characteristics of samples left outdoors for one year as detailed in ASTM-E 160-50. The combustion temperatures of the samples left outdoors were similar upon impregnation with either Tanalith-E or Wolmanit-CB. However, the combustion temperature of the samples treated with synthetic varnish was lower than those that were treated with water-based varnish. The time to collapse and the total duration of combustion of the samples left outdoors were shorter for those impregnated with Wolmanit-CB. Weight loss of the samples left outdoors was higher for those that were impregnated with Tanalith-E and treated with water-based varnish. Gas analysis of the samples that were left outdoors indicated that the O-2 content of flue gas from samples that were impregnated with Wolmanit-CB and treated with synthetic varnish was high and the CO content of flue gas from the same samples was low.

Chemical impregnation of black spruce was conducted to enhance the wood embedment capacity. The formulation was made of 1,6 hexanediol diacrylate, trimethylpropane triacrylate, and a polyester acrylate oligomer. A second formulation, same as the first but with 1% wt of SiO2 nanoparticles, was selected to investigate the potential of nanoparticles and to improve the efficiency of the treatment. The wood embedment capacity was carried out by a dowel-bearing test, which was performed for the two treatments and for an untreated wood group. Both treatments showed an increase of strength of nearly 50% when compared to untreated samples. Micrograph views revealed that the impregnation solution penetrated into the wood only up to 100 μm. Hence, with low chemical consumption, the structural bearing capacity can be significantly increased.

Sorption of metal ions from aqueous solutions to birch wood and spruce heartwood and sapwood has been studied. Functional groups in wood were determined by acid-base titrations. The sorption of metal ions to wood of the different tree species was investigated by a column chromatographic technique. The mechanism of sorption is mainly ion exchange by complexation of metal ions to the functional groups, e.g. carboxyl groups and phenolic hydroxyl groups, in the wood phase. By combination of the sorption experiments with four different metal ion mixtures, the following affinity order was established for spruce sapwood particles: Fe3+>>Pb2+>>Cu2+>>Fe2+>Cd2+>Zn2+>Ni2+>Mn2+≥Ca2+≥Sr2+≥ Ba2+>>Mg2+>>K+>Na+≈Li+. For all three types of stemwood studied, the affinity orders were almost the same. The ion exchange properties of wood were comparable to those of a weakly acid cation exchanger. The affinity order obtained for the synthetic resin was quite similar to the order given above for wood. The metal sorption properties of wood materials imply that they could be a potential material for removal of metal ions from aqueous solutions.

The aim of this study was to investigate the effects of oxygen and moisture content (MC) on the chemical and color changes of black locust (Robinia pseudoacacia) wood during heat treatment. The wood flour was conditioned to different initial MCs and heated for 24 h at a constant temperature of 120ºC in either oxygen or nitrogen atmosphere. The pH values and chromaticity indexes were examined. Diffuse reflectance UV-Vis (DRUV) and Fourier transform infrared (FTIR) spectra were used to characterize the changes of chromophores upon heating. The study demonstrated that the pH values decreased after heat treatment, and it was lower when the heat treated was in oxygen than in nitrogen. The L* decreased significantly, while a* and b* increased. The total color difference ΔE* increased with increasing initial MC until a plateau was reached after 30% MC. The color change was greater in oxygen than in nitrogen. The hydroxyl groups decreased after heat treatment. The releases of acid and formation of quinoid compounds and carboxylic groups during heat treatment were confirmed. Discoloration of wood is due mainly to the condensation and oxidation reactions, which are accelerated by oxygen. Higher MCs are required to obtain the greatest color change of wood in inert atmosphere.

A study was carried out to assess the dust emission and working conditions in the bamboo and rubberwood furniture manufacturing industries in Malaysia. The emission of wood dust arising from these industries was measured in each main work station in the mills. Meanwhile, a questionnaire-based survey was conducted among 5900 workers in 45 companies to obtain information on the occupational accidents that occurred in the mills. The data were collected, compiled, and analyzed using the SPSS package. The highest dust emission from the sanding operation resulted in respiratory ailments among workers. The occurrence of injuries particularly to the hand, wrist, fingers and forearm was due to the prevailing working conditions, safety climate and workers characteristics. The dust exposure levels and working conditions were much more severe in the bamboo furniture manufacturing industry. As a result, a review of existing of dust exposure levels in the woodworking industry is warranted.

High-temperature thermomechanical pulps (HT-TMP, defibrated at 150 to 170 degrees C) were compared to a reference TMP (defibrated at 130 degrees C) as a reinforcement for polylactic acid (PLA). Composites were prepared by melt compounding, followed by injection molding, gradually increasing the used fiber content from 0 to 20 wt.%. The injection-molded specimens were characterized by tensile and impact strength tests, scanning electron microscopy, water absorption tests, and differential scanning calorimetry. The TMP fiber damage was also characterized before and after melt compounding by optical analysis. At 20% fiber content, the Young's modulus increased significantly, while the tensile strength remained unchanged and the impact strength decreased slightly. All fibers suffered damage during melt compounding, but the tensile strength remained about the same as in pure PLA. All types of TMP were able to increase the PLA rate of crystallization. The HT-TMP fibers were dispersed more evenly in PLA than the 130degrees C TMP. The 170 degrees C TMP produced composites of lower water absorption than the other two TMP types, probably because of its lower hemicellulose content and its higher surface coverage by lignin.

Moisture in wood acting as a plasticizer will strongly affect the wood’s viscoelastic properties. However, achieving the desired moisture content (MC) at elevated temperatures during creep tests is difficult. The aim of this study is to accurately and systematically investigate the creep behavior of birch wood at high temperatures. Experiments were conducted using a dynamic mechanical analyzer with a relative humidity accessory coupled with polyvinylidene chloride (PVDC) film for wrapping samples. Creep behavior was examined at six MCs (0%, 6%, 12%, 18%, 24%, >30%) and 11 temperatures (5 to 105 °C). The MC of wood was strictly and accurately controlled during creep tests. Instantaneous compliance (IC) and creep compliance (CC) increased with the increase of both temperature and MC, with significant changes at higher temperatures and MCs. The effects on IC and CC were more pronounced when the subject was influenced by MC, with readings approximately three times and one time greater than those influenced by temperature, respectively. Dramatic increases in CC were found at certain temperatures and MC values. There was a complex interaction between temperature and MC on IC and CC.

The feasibility of using near-infrared spectroscopy (NIR) to identify wood species was investigated in this study. Case I considers the principal component analysis scores plot of NIR spectra for three wood species. Case II considers whether NIR combined with partial least squares discriminant analyses can be used to identify the three wood species. Three wood species were studied, and each species included five randomly collected wood blocks, 21 samples for each wood block, and 315 total wood samples. In case I, the samples in the PCA analysis were clustered together. In case II, samples in the training set were classified into the correct group, and the accuracy of the test set was up to 90%.

Interfacial compatibility plays a key role in the performances of natural fiber-reinforced composites. The measures commonly used to improve the interfacial compatibility focus more on the addition of various compatibilizers than on the structural modification of the natural fiber. In this paper, an attempt was made to enlarge the interfacial interaction areas of the recycled polyethylene (rPE)/wood flour (WF) composites by steaming the WF. Multi-monomer graft copolymers of polyethylene (GPE) were used as compatibilizers for the composites. How the enlarged interfaces affected the morphology, mechanical properties, water resistance, thermal stability, and dynamic rheological properties of the rPE/WF composites was investigated. The steaming process was able to enlarge the voids of the WF and therefore activate more interfaces for interactions. It was found that the interfacial morphology of the composites was affected by the degree of interfacial compatibility of the composites and so was characterized by various distinctive blossom shapes having a variation of compositions. With the help of GPE, the steaming process was able to significantly improve the interfacial compatibility of the composites and therefore improve the mechanical properties, water resistance, thermal stability, and dynamic rheological properties of the composites.

The effects of thermo-compression on the physical properties such as bulk density, mass yield, surface area, and also adsorption capacity of activated carbon were studied. The activated carbon samples were prepared from thermo-compressed and virgin fir-wood by two methods, a physical activation with CO2 and a chemical activation with KOH. A preliminary thermo-compression method seems an easy way to confer to a tender wood a bulk density almost three times larger than its initial density. Thermo-compression increased yield regardless of the mode of activation. The physical activation caused structural alteration, which enhanced the enlargement of micropores and even their degradation, leading to the formation of mesopores. Chemical activation conferred to activated carbon a heterogeneous and exclusively microporous nature. Moreover, when coupled to chemical activation, thermo-compression resulted in a satisfactory yield (23%), a high surface area (>1700 m2.g-1), and a good adsorption capacity for two model pollutants in aqueous solution: methylene blue and phenol. Activated carbon prepared from thermo-compressed wood exhibited a higher adsorption capacity for both the pollutants than did a commercial activated carbon.

The weathering performance of wood coated with a combination of rutile TiO2 hierarchical nanostructures and a sol-gel deposit of alkoxysilanes was determined by exposing three sets of specimens to UV light and water spray. The first set consisted of specimens coated with a mixture of methyltrimethoxysilane (MTMOS) and hexadecyltrimethoxysilane (HDTMOS). The second set consisted of specimens coated with nanostructural TiO2 followed by a mixture of MTMOS and HDTMOS. The third set consisted of uncoated control specimens. The wood coated with TiO2 followed by a mixture of MTDMOS and HDTMOS exhibited significantly less surface color change and weight loss as a result of UV light-induced degradation and erosion from water spray in comparison with the other groups. However, the coated surfaces were gradually transformed from hydrophobic to hydrophilic. Despite this apparent weakness, the MTMOS/HDTMOS/TiO2 coating, with superior photostabilization properties and resistance to surface erosion, may be useful for improving the weathering performance of wood coated with semi-transparent wood stains.

Utilizing wood powder and corn starch as the main materials with polyurethane adhesive as a cross-linking agent, the starch/wood powder composite material was prepared via molding forming techniques. The effects of wood powder mesh and addition of wood powder on the properties of composite material were investigated. The compatibility of starch and wood powder and the thermal stability of composite were evaluated by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMA), respectively. The mechanical properties and water absorption of composite material were also tested. The results showed that the mechanical properties and water resistance of composite material first increased and then fell with increasing mesh, and the best performance was obtained when the mesh ranged from 80 to 100. The best compatibility, mechanical properties, water resistance, and thermal stability of composite material was obtained with 10% polyurethane crosslinking agent addition.

This research was conducted to determine the impact bending strength and dynamic bending strength of Norway spruce wood from Slovenia. An accelerometer was added to the impact pendulum in order to capture the material’s response to an instantaneous load. Impact bending strength of specimens were determined by standard method measuring the height of pendulum before and after the break. While measuring the impact pendulum decelerations during the fracture of the specimen, the impact bending strength and dynamic bending strength was calculated. Correlations between the measured properties were determined, for which the R2 was in the range 0.88 to 0.51 between the standard and accelerometer method and between the impact bending strength and dynamic bending strength, respectively. The results confirmed that the methods used to determine the impact bending strength were comparable and that it was possible to determine dynamic bending strength on the basis of impact pendulum deceleration measurement.

This article discusses the production potential (and limits) of the forests in the Czech Republic (CR). The calculation respects ecological limits set by typological system and the Czech forestry legislation. The key criterion of the production evaluation is the total mean increment. Usually, a forest owner can choose amongst several variants of management. The analysis in this work examines the two limit variants – the minimum and maximum production potential. The results show that, e.g., the Norway spruce share might be 19 to 48% of the total area of Czech forests (51.4% at present). The target management the owners opt for (Norway spruce, pine, oak, and beech) can, in the future, influence the timber processing industry, the main purchaser of timber raw material from Czech forests. The maximum variant shows 9,134 thousand m3 of available coniferous round timber, while the minimum one only 3,802 thousand m3 per year. Therefore, the timber processing industry should keep a close watch on the situation and either try to persuade forest owners to choose the alternative of the target management that would provide sufficient assortment for timber processing, or adjust the manufacture to the possible changes in the species composition of the forests.

Moisture adsorption and hygroexpansion behaviors of southern pine (Pinus spp.) treated with 0.5, 1, and 2% concentrations of paraffin wax emulsion were investigated. The specimens, 4 mm along the grain and 20 mm in radial and tangential directions, were exposed to seven different relative humidity conditions of 11, 22, 33, 45, 60, 75, and 92% for adsorption at 30 °C, which was controlled by a self-designed temperature conditioning chamber. Weights and transverse dimensions of the specimens were measured at certain time intervals during the adsorption processes. Results showed that paraffin wax emulsion treatments could reduce both equilibrium moisture content and adsorption rate. Additionally, paraffin wax emulsion treatments also improved dimensional stability, as indicated by estimation of the humidity expansion coefficient (Y) as well as moisture expansion coefficient (X).

Superhydrophobic organic-inorganic composite nanocoatings were fabricated on the intrinsically heterogeneous surfaces of wood using silica-polymer hybrid materials, which were prepared through sol-gel chemistry using tetraethoxysilane (TEOS) as an inorganic precursor and hexadecyltrimethoxysilane (HDTMS) as an organic modifier. The long-chain HDTMS acts not only as a hydrophobic agent to lower the surface free energy of the silica particles but also as a bonding agent to aggregate the nanoparticles by polymerization. The degree of aggregation of the silica particles in the coating can be controlled by adjusting the initial concentration of HDTMS, and hence the surface morphology and roughness of the coated wood are tuned. When the concentration of HDTMS reaches a critical level, the formed aggregates of silica particles in combination with the inherent microscale roughness of wood appear to create hierarchical micro/nanostructures on the wood substrate, allowing for the generation of superhydrophobicity. The silica-polymer hybrid coatings on the wood surface are robust enough to withstand high humidity as well as strong acid and alkali whilst retaining its superhydrophobicity. The coatings also exhibit satisfactory durability against water leaching without significantly changing its hydrophobicity, highlighting their potential for outdoor applications.