European Journal of Wood and Wood Products最新文献

The main objective of this study was to evaluate the mechanical properties of three thermal-modified wood species when exposed to weathering in urban and maritime/industrial environments and their durability against subterranean termites. The wood species studied were Maritime pine, ash, and blackwood acacia. All wood samples were exposed to two different environments (urban and maritime/industrial) for 24 months. Then, its physical and mechanical properties were evaluated (modulus of elasticity (MOE), modulus of rupture (MOR), compression strength (CS), and modulus of compression (MOC). Thermally modified woods revealed a lower density, which could explain the loss of MOE and MOR. In compression, no significant changes were verified. The weathered samples showed changes in mechanical properties, mostly verified in MOE and MOR, where some decreases were reported in both locations. Tests were performed to evaluate biodegradation and the resistance of all wood samples to subterranean termites. The grade of attack (≈4) and termite survival rate were similar in all wood species (above 75% and lower than 80%), except for modified acacia (59%), which could indicate that thermal modification increased toxic substances. The cellulose degradation was reflected in FTIR-ATR and Py-GC/MS in natural and thermally modified woods. Py-GC/MS showed a decrease in levoglucosan, while lignin suffered some modifications with slight changes in monomeric composition reflected by the reduction of the S/G ratio. No changes were found between the two environments, and thermal modification did not give extra protection against termites and weathering.

Furniture manufacturing plants are mainly small to medium enterprises (SMEs) and must merge customized mass production into their schedule to meet the market demand. Furniture plants produce a diverse array of models, with each process uniquely adding to the costs. In this multiproduct, multipart and multi-process manufacturing, it is difficult to accurately predict the processing time of new models and the lead time for highly customized orders. The processing time of parts is critical for optimizing, estimating the lead time and pricing the products, particularly for new models. Machine Learning (ML) is a useful tool to analyze and control manufacturing parameters and could be applied to furniture factories too. In this study the authors demonstrated the use of a ML-based framework to predict the processing time of wooden furniture based on the design of parts and actual manufacturing data. Specifically, the objectives are to define the accuracy of Convolutional Neural Networks (CNN) in classifying furniture parts according to their design characteristics into categories such as Plain, 2D, and 3D curved, and define the accuracy of Artificial Neural Networks (ANNs) in taking CNN data along with real manufacturing processing time data for identifying and analyzing intricate correlations between parts and manufacturing processes, thereby facilitating precise prediction of processing time. Images of the furniture’s parts design and data from a time and motion study in mass production in a plant were used to develop the models. The models' R², Mean Squared Error (MSE) and Mean Absolute Percentage Error (MAPE) were calculated as a criterion for defining accuracy. Random Forest and Gradient Boosting regression models were developed to compare and validate against ANN for predicting processing time, ensuring the robustness and reliability of the ML-based framework. All four models showed successful performance with R² scores above 0.90, MSE below 1, and MAPE below 10, except 10.26 in Random Forest and 11.15 in Gradient Boosting. However, ANN showed significantly higher accuracy than other traditional regression models comparing MAPE of 1.63 to 10.26 in ANN and Random Forest respectively demonstrating its better performance in analyzing intricate relationships of input features and outputs.

Prehydrolysis kraft is the industrial process most frequently used to produce dissolving pulp using continuous or batch technologies. Wood prehydrolysis is the most critical step in the dissolving pulp production stages, aiming at removing hemicelluloses before wood pulping, as hemicelluloses tend to impair cellulose reactivity during the dissolving pulp derivatization process. The performance and extent of this process can be controlled mainly through retention time and temperature conditions, with the P-factor being the severity parameter used to correlate both variables in pulp mills. This study assesses the effects of the P-factor on the prehydrolysis process of eucalyptus clone wood used for dissolving pulp production, deriving regression models to aid in the decision-making and optimization of this process. Five trees from two clones—Eucalyptus urophylla and E. urophylla × E. spp. at the ages of 3 and 5 years—grown in plantations located in Bahia State, Brazil, were evaluated. Hydrothermal pretreatments were applied to wood chips under different time and temperature conditions (P-factor), and the chemical characteristics of the treated wood (lignins and carbohydrates) were determined. The experimental design provided a comprehensive view of the severity factor's effect on each wood macro-component, showing the threshold at which the required amount of hemicelluloses was removed without affecting the cellulose fraction. Hemicelluloses solubilization and removal extended up to 90% within the experimental conditions, with the optimized point achieved at a P-factor of 873. The regression models produced showed good fit for process yield, hemicellulose, and lignin removal.

With the rising demand for environmentally friendly construction materials in the building and construction industry, this study explores mineral-based compounds as a sustainable alternative to certain harmful chemicals. The focus of this research is to improve the mechanical properties of wood by utilizing magnesium oxychloride (MOC) as a mineral, aiming to minimize adverse environmental effects. The study investigates the mechanical characteristics of heat-treated and non-heat-treated fir wood post-mineralization with magnesium-based compounds. The samples were subjected to impregnation using the Bethel method, employing magnesium oxychloride through two distinct techniques: a combined treatment and a separate treatment. Subsequent to impregnation, the bending strength, modulus of elasticity (MOE), hardness, impact resistance, glue line shear strength (using polyurethane and polyvinyl acetate adhesives), and screw withdrawal resistance of the samples were assessed. The findings revealed an increase in density and enhancement in overall mechanical properties. Notably, the combined impregnation method yielded the highest values for bending strength, MOE, hardness, impact resistance, glue line shear strength, and screw withdrawal resistance in both treatments. The results for glue line shear strength demonstrated the highest value with polyurethane adhesive and the lowest with polyvinyl acetate adhesive. Furthermore, the outcomes from screw withdrawal resistance, in both perpendicular and parallel directions to the grain, showcased greater resistance in the perpendicular orientation for both treatments. These results suggest that the impregnation of heat-treated and non-heat-treated wood with magnesium compounds (oxide and chloride) effectively bolsters the mechanical properties.

Mold is a common cause of degradation and decay of wood furniture and structures, leading to health risks and loss of aesthetics. Several coating methods have been developed to bestow mold resistance to wood surfaces. However, few studies have utilized photodynamic inactivation (PDI) as the mold inhibition mechanism for wood coatings. In this study, a polysiloxane-based coating incorporated with Rose Bengal Lactone (RBL) as a photosensitizer was developed on poplar woods at loadings of 0.1, 0.2, and 0.4 mg ml^− 1. The polymeric coating was hydrophobic, with the highest water contact angle of 128.20° and demonstrated resistance to scratches during handling. The anti-mold performance was tested against the soft-rot fungus Chaetomium globosum. The polymer-coated wood samples were incubated with and without light irradiation. The dark cultures showed growth inhibition on the coated surface due to surface hydrophobicity and smoothness. Following irradiation by green light at 530 nm, complete inhibition of mold growth was observed at the end of two weeks at coating loadings above 0.2 mg ml^− 1. The photodynamic activity of the coating under visible light exposure was observed to be stable even after a period of 3 months. The coating developed here offers a viable solution for anti-mold applications under common lighting conditions.

This study investigates how the impregnation of ultra-low molar ratio urea-formaldehyde (UL-UF) resins with formaldehyde to urea (F/U) mole ratio of 0.8 at various curing temperatures affects wood characteristics, including density, weight percent gain (WPG), weight loss (WL), and anti-swelling efficiency (ASE). The UL-UF resins were synthesized using a modified alkaline-acid-alkaline process, resulting in low viscosity, low crystallinity, and low curing temperature of resins. The impregnation technique started by immersing sengon (Paraserianthes falcataria L. Nielsen) wood in UL-UF resins at a volume ratio of 1.0:1.1, subjecting to a vacuum of -50 cmHg for 30 min, and applying 7 kgf.cm^-2 of pressure for 3 h at 25 ± 2 °C. The treated wood was cured at temperatures of 120, 140, 160, and 180 °C for 30 min. This research revealed that there was a successful in-situ modification of wood with UL-UF resin, as confirmed by SEM micrographs, XRD and semi-quantitative FTIR analysis. The UL-UF-impregnated wood had a higher WPG and density than untreated wood. Greater curing temperatures were linked to decrease WPG, density, and WL values, but higher ASE. Lowering the curing temperature induces higher WL and decreased ASE owing to under-curing in the core layer, while raising the curing temperature promotes faster curing and gelation time, resulting in the opposite effect.

This study investigated the potential for Melaleuca rhaphiophylla bark to be made into a sustainable engineered wood product. Boards were manufactured from M. rhaphiophylla bark by hot pressing them without the use of any additional binders or other chemical treatments. Sheets of bark were pressed for 20 min at temperatures of 90 °C, 120 °C, 150 °C, 180 °C and 195 °C and pressures of 1, 2 and 3 MPa. Samples of the boards underwent three-point bending, water absorption and impedance tube testing to determine their Modulus of Rupture (MoR), Modulus of Elasticity (MoE), thickness swelling, water absorption and sound absorption potential. Linear mixed effects (LME) models were used to identify correlations between the condition of the bark and hot-pressing parameters with the properties of the final boards. The MoR, MoE and thickness swelling properties of the boards were found to be similar or superior to other bark-based alternatives. Water absorption was similar to commercially available plywood and medium density fibreboard (MDF) control materials, sound absorption was higher, but MoR and MoE were lower. M. rhaphiophylla bark boards show potential to be suitable alternatives for medium density fibreboard and plywood including uses in cabinetry or veneers with further development.

This study, which evaluated the effects of biological pretreatment on comminuted pine and poplar shavings and particleboards with urea–formaldehyde resin (UF), utilising Pleurotus ostreatus (P. ostreatus), holds statistically significant implications for the future of waste management and biogas production. The 17-week fungal pretreatment was followed by a physicomechanical and chemical analysis of raw and pretreated materials and pressure agglomeration to produce pastilles and an anaerobic digestion process to produce biogas. The specific density and strength parameters in radial and axial compression were determined for the produced pastilles. The pretreatment notably reduced lignin content by 6.8–8.3%, which increased mechanical parameters, angles of internal friction, cohesion, shear, and consolidation stresses and positively affected agglomeration efficiency and increased pellet density. Values for the specific compaction work of treated biomass were higher than those of raw biomass (24.03 vs. 21.70 kJ kg⁻¹), correlating with the production of denser pastilles (1014 vs. 959 kg m⁻³). After pretreatment, enhanced structural properties of the biomass (lignin and hemicellulose components decreased, and cellulose content increased) facilitated increased methane yields, showing up to a 3.7-fold increase for pine and 2.9-fold for poplar UF particleboards. This research advances the potential for developing recycling and biogas technologies, offering novel insights into UF degradation via fungal pretreatment. The findings underscore the necessity for further detailed studies to analyse changes in resin content post-pretreatment and their impact on the properties of wood materials.

The goal of this study was to determine the quantity and quality of wood extracted from the structural parts of wooden buildings to facilitate the most appropriate allocation of the material. An additional aim was to provide a reliable and consistent characterisation procedure for recovered wood, according to its physical characteristics, such as dimensions, the presence of cracks etc. From a sample of recovered wood collected from the demolition of a wooden building in Espoo, Finland, it was found that around 30% of the total volume of material could be recovered for repurposing or remanufacturing into solid wood products, provided structural integrity can be ensured. The samples of recovered wood were relatively short compared to virgin timbers, averaging 88 cm. Further, it was determined that removing metal contaminants does not necessarily improve material recovery, because cracks, wane, warping, as well as machining the recovered wood to standard dimensions, impact material recovery the most.

Structural performance of timber buildings can be adversely affected by exposed harsh environment and sustained load. This study investigates bending performance degradation of glued laminated timber (GLT) beams (50 mm × 50 mm × 950 mm) that are exposed to unfavorable environmental conditions. The experiments consider eight scenarios, including various climate cycling periods, duration, and stress levels. Eight groups of GLT beams were exposed to the different scenarios for four stages, then loaded by short-term bending to obtain the MOR and MOE. The results showed that coupling effects of sustained loading and the environmental factors such as UV-light and mist spraying aggravated the pronounced damage on the laminates and gluelines and caused the degradation of strength and stiffness. The highest degradation rate occurred in the first stage. In the relatively mild environments, some performance recovery was observed in the later stages, most specimens exhibited ductile failure accompanied by the significant increase of the ultimate deflection with the exposure time. While in the harsh environments, the MOR and MOE degradation was evident and continuous, more specimens experienced brittle failure, and the increase of the ultimate deflection slowed down greatly with the exposure time. Additionally, the effects of sustained loading period were significantly exacerbated under the harsh environmental conditions, the specimens loaded by less than 50% stress level exhibited the distinguished degradation in 24 days.