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The histogenesis of reaction wood in woody plants is a promising area of exploration for emerging wood technology products and for a generalized understanding of stress physiology. The activity of total protein and antioxidant enzymes were measured during the development of normal and reaction wood (opposite wood and tension wood) in the bole of poplar trees (Populous alba L.) induced by two levels of sustained bending stress to produce moderate and severe reaction wood. Four-year-old poplars were induced to produce reaction wood by sustained bending to 0, 35 and 80° from the vertical position. The activity of antioxidant enzymes was studied with repeated sampling during one growing season. Severe reaction wood showed higher levels of H2O2 and enzymes than moderate reaction wood. Tension wood showed a higher accumulation of total protein than opposite wood at the beginning and end of the bending treatment and opposite wood showed higher enzymatic activity. H2O2 and antioxidant enzymes were also sensitive to mechanical bending stress; compared to normal wood, tension wood and opposite wood which showed higher enzymatic activity coupled with higher amounts of total H2O2. Ascorbate peroxidase was more active than glutathione peroxidase in both tension and opposite wood at some periods of sampling. [ABSTRACT FROM AUTHOR]

Thermogravimetric analysis (TGA) was performed on five softwood and five hardwood thin wood samples in the longitudinal (L) and radial (R) directions. Dimensional changes were monitored using a charge-coupled device camera under a nitrogen flow. A comparison of the TG and derivative TG (DTG) curves revealed that shrinkage in the R direction began when the weight was reduced to 79–92% at 305–330 °C and 87–96% at 275–290 °C for softwoods and hardwoods, respectively. Hemicellulose is mainly degraded in this temperature range. In contrast, shrinkage in the L direction started at temperatures close to the DTG peaks, i.e., 360–380 °C and 345–370 °C, respectively, at which temperatures cellulose is mainly degraded. In general, the R/L shrinkage anisotropy was greater for hardwoods than for softwoods, but the species variation was large and the magnitude was directly related to the difference in the shrinkage onset temperatures between the R and L directions, regardless of the wood species. Therefore, shrinkage anisotropy can be attributed to the relative reactivity of hemicellulose and cellulose in wood cell walls. The shrinkage mechanism during carbonization is discussed in terms of the cell wall ultrastructure, in which cellulose microfibrils are covered by a hemicellulose–lignin matrix, and the orientation of the cells in the L and R directions. [ABSTRACT FROM AUTHOR]

Wood is a primary building tool for ancient buildings and structures, but for those that survive to date, naturally aged wood may pose a noteworthy fire hazard. There are potential risks to health, safety, and substantial cultural loss if fire risks in such buildings are not mitigated. We obtained several samples of aged wood commonly used in ancient structures (elm, pine, and aspen), and compared the kinetic and thermal characteristics to fresh wood examples to determine potential methods of enhancing safety. Differential scanning calorimetry was used to establish the heat release characteristics of the fresh and aged samples, and the characteristics of the thermal reaction stages were characterized using the temperature range and heat release laws for each reaction stage. The heat release characteristics during combustion were investigated for different heating rates, and the influence of aging on temperature change and heat release rate characteristics during different exothermic stages was assessed. Finally, using heat flow data, the apparent activation energy (AAE) of the samples and their distributions during different exothermic stages were calculated and analyzed via the Friedman differential iso-conversion method. Results showed that the exothermic energy of the aged samples was higher than that of the fresh samples, indicating that aging does impact the thermal reaction process. The aged samples in this study had a greater heat diffusion capacity, transmitted more heat, were more susceptible to burning (by spreading that heat), and generally posed a greater fire hazard. During the rapid exothermic phase, the AAE of aged wood increased as the reaction progressed, and exhibited lower AAE with a greater sensitivity to fire than fresh samples. A sound linear relationship between pre-exponential factor and AAE and the kinetic compensation effect was obvious. This study provided a rudimentary theoretical basis for the prevention of fires in timber-framed ancient buildings. [ABSTRACT FROM AUTHOR]

Wood densification is a technique to enhance wood density and hardness, presenting a promising solution to expand wood use across various applications. However, current densification methods have cost and environmental impact limitations. This project introduces a potential environmentally friendly approach involving surface chemical densification through in-situ polymerization, using carbon Michael addition reaction between biobased acrylate and malonate monomers. This reaction, conducted in mild conditions with low energy and solvent consumption, aims to enhance wood densification while minimizing environmental impact. Various malonate-acrylate systems were formulated, and were optimized based on their viscosity, conversion rate, glass transition temperature, crosslinking density, and hardness. Then, sugar maple wood samples were densified with the best formulations. Monomers with lower viscosity demonstrated higher chemical retention. Density profile and penetration depth were also higher for the samples impregnated with lower viscosity formulations, which was confirmed by scanning electron microscopy. Confocal Raman spectroscopy confirmed that formulations successfully filled lumens and vessels without reacting with the cell wall components. Brinell hardness was used to determine the hardness of natural and densified woods. One-way ANOVA data analysis showed a significant increase in hardness of densified samples compared to untreated wood; however, based on TUKEY Anova analysis, no noticeable difference was reported between impregnated samples with different formulations. Overall, results showed the potential of the Michael addition reaction in wood impregnation. [ABSTRACT FROM AUTHOR]

This study utilized a self-developed gas permeability–porosity integrated analyzer to examine the gas permeability and porosity of pine, cypress, and Cunninghamia conifers across different wood orientations and parts. The findings reveal that the longitudinal permeabilities of conifers are higher than the radial and tangential permeabilities by factors of 14–100 and 275–600, respectively. A consistent exponential relationship exists between longitudinal permeability and porosity, irrespective of species. In the sapwood, the tracheid dimensions are 110.5–132.1% in radius and 103.6–116.2% in length compared to heartwood. A single tracheid exhibits higher longitudinal flow resistance than those in the radial and tangential directions. The primary longitudinal flow resistance stems from the lap surface of the upper and lower tracheids series connected with pits. In radial and tangential directions, the gas flow encounters a high density of pits from a series of connected tracheids. The number of series-connected tracheids in the longitudinal direction is only 1% of those in radial and tangential directions, whereas it reaches up to 600 times for parallel connections. This leads to considerably lower total flow resistance in the longitudinal direction compared to radial and tangential directions. The measured higher longitudinal gas permeability aligns well with the model calculations and the gas microseepage is predominantly related to tracheid structure, causing permeability variations. [ABSTRACT FROM AUTHOR]

High variations in juvenile wood properties in the radial direction and its worse performance than mature wood make it less suitable for some applications and often treated as waste material. This study aimed to assess how thermal modification affects the chemical composition and the physical, mechanical and swelling properties of Scots pine juvenile and mature wood. An additional goal was to evaluate if the modification can equalise the differences in selected properties of juvenile wood to those of mature wood so that from waste material, juvenile wood can become a fully-fledged raw material for various industrial applications. Thermal treatment at 220 °C influenced wood chemical composition, degrading mainly hemicelluloses but also affecting cellulose and lignin, which resulted in a reduction of hydroxyls and carbonyl/carboxyl groups. These changes were more pronounced for mature than juvenile wood. It reduced mass loss and swelling rate, and increased swelling pressure in the tangential and radial directions to a higher degree for juvenile than mature wood. Changes in mechanical properties in compression were statistically significant only for mature wood, while wood hardness remained unaffected. Although the applied heat treatment improved the performance of juvenile wood by reducing its swelling rate, it did not equalise the examined properties between juvenile and mature wood. Since higher juvenile wood proportion is expected in the wood supply from the future intensively managed forests, there is still a need to find suitable modification methods or better processing techniques so that instead of being thrown away as waste, it could be used broadly in various industrial applications. [ABSTRACT FROM AUTHOR]

Developing a moisture-stable structural material with high toughness is essential for improving the stability of packaging and building materials. Wood is a pervasive structural material with naturally good mechanical properties. However, insufficient moisture stability and toughness compromises its safety and structural requirements. Herein, we constructed a moisture-stable wood veneer with high toughness by assembling the choline chloride-ethanolamine delignified wood with alkali lignin, followed by hot-pressing to densify the material. Lignin can be assembled into the microchannel of the delignified wood as a filler and binder for reducing molecular transportation and increasing internal bonding. The enhanced tensile strength (582.0 MPa) and strain (3.6%) are accompanied by a significant increase in the toughness to 11.1 MJ/m3, which is 37 times higher than that of natural wood. The excellent mechanical property can be preserved to a large extent after retaining in tropic moisture conditions (38 °C, 90% RH) with retention of 66.2% and 60.8% for tensile strength and toughness, respectively. A stable water contact angle on the surface and limited water adsorption of reconstructed wood indicate a lowered water infiltration velocity, suggesting highly improved moisture stability as needed for structural materials. [ABSTRACT FROM AUTHOR]

During the dehydration of waterlogged archaeological wood (WAW), shrinkage inevitably occurs due to capillary force and hydrogen bond recombination as WAW loses free and adsorbed water. Existing drying techniques, including solvent displacement, freeze-drying, and supercritical fluid drying, only take effect by reducing or eliminating the surface tension of liquid. Nonetheless, the contribution of hydrogen bond recombination in shrinkage has long been neglected and a countermeasure concerning this problem is needed. In this study, we propose a simple aqueous phenylboronic acid (PBA) treatment that can help improve dimensional stability and reduce hygroscopicity of WAW. Analysis by Fourier transform infrared spectroscopy, density functional theory calculation and dynamic vapour sorption reveal that PBA can incorporate with hydroxyl groups (–OH) on cellulose through coordination and hydrogen bonds, occupy the water-cellulose binding sites, and possibly inhibit the formation of hydrogen bonds between adjacent cellulose chains. [ABSTRACT FROM AUTHOR]

Considering the bioactive composition and therapeutic interest of Ficus carica, much research has been conducted on its fruits and leaves. However, there has been relatively little investigation regarding the wood bark, despite its potential as a rich source of phytochemical compounds with diverse biological activities. The aim of this work is the determination of the phenolic composition of the wood bark extracts of F. carica from three cultivars (Aberkane, Aghanime, and Bakour) and the assessment of their potential cytotoxicity and bioactive capacities such as antioxidant, anticancer, and anti-inflammatory activities. The phytochemical compounds were identified and quantified using UPLC-ESI-MS. The results revealed that Aberkane wood bark cultivar had the highest content of total polyphenols and ascorbic acid, while Aghanime cultivar had the highest content of flavonoids. The wood bark of the Aberkane cultivar exhibited the highest DPPH and ABTS scavenging activities (48.55% and 71.81%, respectively). This extract exhibited strong cytotoxic effects against cancer cell lines MCF-7 (IC50 143.30 µg/mL) and carcinoma HepG2 (IC50 240.18 µg/mL), as well as potent anti-inflammatory activity demonstrated by the BSA assay and inhibition of NO production in RAW 264.7 cells. Aghanime wood bark extract exhibited the highest ORAC value (446.078 µmol TE/g). However, the Bakour wood bark cultivar was particularly noteworthy for its iron-chelating properties. The UPLC-ESI-MS analysis revealed the presence of various phenolic compounds, notably chlorogenic acid and rutin. These findings demonstrate that the wood bark extract of fig possesses a diverse range of beneficial biological activities, which are associated with its phytochemical composition. [ABSTRACT FROM AUTHOR]

Eucommia ulmoides wood is renowned for its high quality, however, there is a lack of research regarding the assessment of its structure and properties. This gap was addressed in the present study by examining three clones of E. ulmoides [Huazhong 12 (HZ), Cili (CL), and Miye (MY)] to compare their growth and structural characteristics, chemical components, and physical and mechanical performance. We employed a comprehensive evaluation model, combining the coefficient of variation method and rank sum ratio comprehensive evaluation method, to comprehensively assess the wood samples' structures and properties. The results reveal significant differences at the P < 0.05 level among the three clones in various parameters including tree height, ground diameter, number of internodes, cell wall area ratio, number of vessels per unit area of early and late wood, wood fiber lumen diameter and double wall thickness, fiber length and width, hemicellulose content, lignin content, air-dried density, dry shrinkage properties, wet expansion properties, compressive strength, bending strength, and bending elastic modulus. Among HZ, CL, and MY woods, CL exhibited superior development as well as physical and mechanical properties. HZ showed exceptional chemical properties, while MY demonstrated the finest cell morphology. By utilizing the proposed evaluation model, we comprehensively assessed the structures and properties of three different clones of E. ulmoides wood. All samples were categorized into upper, middle, and lower grades based on their respective characteristics. HZ was found to be distributed across all three grades, with the highest presence in the upper grade. MY was primarily distributed in the middle and lower grades; CL was predominantly found in the third grade. Among the clones, HZ showed the highest comprehensive score while MY showed the lowest score. The evaluation results indicate that among the three wood clones, HZ achieved superior quality for the fiber industry, CL and HZ are more suitable raw materials for construction industry. The findings of this study may contribute to a theoretical foundation for the selection, grading evaluation, and added value enhancement of E. ulmoides wood. [ABSTRACT FROM AUTHOR]

Wood contains abundant extractives and volatile oils, which release strong odors and hazardous volatile organic compounds (VOCs). The emission of VOCs can be minimized by degrading and mineralizing wood extractives. Wood powder is widely used as raw material for chemical industry, building materials, wood-based boards, and other products. In this study, China fir wood powder was used as object to remove wood VOCs by the ozonation and ozone-activated persulfate (O3/PS) systems, and their VOC removal efficiencies were evaluated using gas chromatography–mass spectrometry (HS-SPME/GC–MS). The result showed O3/PS system exhibited higher VOC removal efficiency. The mechanism of different ozone processes in wood treatment was explored, which contributed to the evaluation of the removal efficiency of VOCs and the degradation pathway of VOC components. The PS dosage, O3 concentration, and pH had varying effects on the O3/PS system. When the pH increased to 10, the removal rate of wood VOCs decreased. The VOC removal rate did not increase with the increasing free-radical concentration. When the PS concentration increased from 5 to 20 mM, the VOC removal efficiency gradually increased from 49.91 to 72.39%. However, when the PS concentration increased to 40 mM, the VOC removal efficiency of PS slightly decreased because the excess PS immediately produced a large amount of hydroxyl radical (·OH) and sulfate radical (SO4·−), which led to quenching reactions between radicals. The results revealed that the O3/PS process promoted indirect oxidation. Under the synergistic effect of O3, ·OH, and SO4·−, the VOC removal efficiency was significantly improved, the intermediate product was lower, and the total VOC removal rate VOCs by O3/PS was more than 70%. [ABSTRACT FROM AUTHOR]

Shorter processes and lower temperatures are critical to reducing thermally modified wood costs. In this study, the exogenous H3PO4 was infiltrated into poplar (Populus × euramaricana) and then heated at low temperatures of 130–170 °C to speed up the thermal modification process of wood with better performance. The hygroscopicity was analyzed by dynamic vapor sorption detection and its constituents of modified wood were characterized by high-performance liquid chromatography and solid-state CP/MAS 13C NMR. The results showed that acid combined with low-temperature thermal modification (acid-LTM) resulted in lower equilibrium moisture content compared with the high-temperature thermal modification (HTM) wood. The addition of H3PO4 triggered severe degradation of the carbohydrates in the wood, and the mass loss of cellulose and hemicellulose were 11.9% and 24.1% when modified with 3.0% H3PO4 at 150 °C, respectively, thereby reducing the quantities of water sorption sites. Besides, the degradation products of carbohydrates crosslinked with the thermally stable lignin to form "pseudo-lignin" substances, leading to an increase in the lignin content of acid-LTM wood. The increase in the crystalline index and crystallite size of cellulose in acid-LTM wood was also conducive to reducing the wood hygroscopicity. The better hydrophobicity of acid-LTM poplar was further verified by its decrease in the water sorption site density and the theoretical OH content compared with HTM wood and unmodified wood. This study will offer a potential process to manufacture thermal-modified wood at a low cost. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable biomass utilization, this study investigates the hydrothermal treatment of birchwood and its subsequent impact on enzymatic hydrolysis lignin (EHL). Additionally, birchwood undergoes processing with NaOH (4% w/w) within a Parr reactor to precipitate lignin from the black liquor, resulting in lignin-rich substrates (LRSs) which are then subject to thorough characterization. Notably, EHL produced after hydrothermal pretreatment at 190 °C exhibits the highest lignin content at 67%, while kraft lignin (KL) obtained at 140 °C (pH 1.5) produces 65% lignin content. Among these LRSs, the KL sample produced at 190 °C (pH 4) stands out, displaying a robust aromatic skeletal structure and an abundance of methoxyl groups, primarily owing to its high purity. Furthermore, for these LRSs' it is shown that chemical configuration influences their thermal behaviour, allowing the lignin to be tailored for diverse applications, from low melting point materials to carbonaceous materials capable of withstanding temperatures exceeding 700 °C. This comprehensive understanding of the chemical, thermal, and physical attributes of LRSs not only enriches our knowledge of lignin-rich substrates but also paves the way for the development of sustainable bio-based materials, marking a step towards sustainable materials development. [ABSTRACT FROM AUTHOR]

Anthraquinone has been widely utilized in the pulp and paper industry as a catalyst for alkaline cooking; however, its application has been recently restricted due to its potential carcinogenic effects. Hence, safer alternatives to anthraquinone have been explored. Agro-industrial by-products have been utilized as sustainable sources of value-added materials. In this study, teak (Tectona grandis) wood waste from Gunung Kidul, Indonesia, which naturally contains lapachol, was utilized as a biocatalyst to enhance delignification and improve pulp yield in alkaline cooking for pulp and paper production. The use of lapachol as a cooking catalyst was investigated for kraft, soda, and prehydrolysis soda cooking. Lapachol accelerated delignification and retained carbohydrate in all three alkaline cooking methods, with its effect being more pronounced in kraft cooking than in soda cooking. This study demonstrates that teak wood extractives with lapachol are promising sustainable catalysts for alkaline cooking. [ABSTRACT FROM AUTHOR]

To investigate the effect of Fe-addition on the Cs+-adsorption ability (Cs+-AA) of woody charcoal, charcoal samples were prepared from Japanese cedar (JC) and Japanese oak (JO) wood impregnated with Fe3+ at 600 and 800 °C. The residual functional groups of the charcoal samples were examined using infrared-photoacoustic spectroscopy. OH groups were observed in the charcoal made at 600 °C, and no vibrational bands were detectable in the charcoal synthesized at 800 °C. The observation of Raman D-, G-, and G´-bands revealed that all charcoal samples contained sp2-carbon atoms but graphitization occurred only in the iron-loaded charcoal made at 800 °C. The Cs+-AA of the JC and JO charcoal samples were evaluated based on the adsorption isotherms of an aqueous CsCl (Cs+: 33 mg/L) solution. The addition of Fe3+ to wood had a negative effect on the Cs+-AA of the JO charcoal made at 600 °C, but a positive effect on the Cs+-AA of the JC charcoal prepared at 800 °C. [ABSTRACT FROM AUTHOR]

Previous research found that some organosilicon treatments proved effective in stabilizing waterlogged wood dimensions during drying. The present research aimed to determine the mechanism of wood stabilization by these chemicals to understand their mode of action. The study used chemically (ChP) and biologically degraded (BP) model Scots pine wood treated with Methyltrimethoxysilane (MTMS), (3-Mercaptopropyl) trimethoxysilane (MPTMS), or 1,3-Bis(diethylamino)-3-propoxypropanol)-1,1,3,3-tetramethyldisiloxane (DEAPTMDS). Synchrotron-based X-ray fluorescence microscopy (XFM) was used to investigate the penetration of organosilicons into the wood cellular structure and cell walls, and nanoindentation was used to study the mechanical properties of the treated wood cell walls. All treatments resulted in high volumetric anti-shrink efficiency (ASEV) values of 74–82%, except for MTMS-treated ChP with an ASEV of 52%. The multiscale XFM results revealed that all applied organosilicons penetrated throughout the whole wooden blocks and deposited in both cell lumina and cell walls. The retention of all applied organosilicons was highest in BP wood, and so was the dimensional stabilization effect. MTMS-treated ChP had the lowest measured cell wall infiltration, which likely contributed to its lower ASEv. DEAPTMDS treatments plasticized the cell walls and resulted in lowered nanoindentation elastic modulus (EsNI) and hardness (H) for all types of wood. MTMS and MPTMS had modest effects on cell wall mechanical properties, and the effect depended on the type of wood. The final effect of organosilicon treatment on the dimensional wood stabilization and mechanical properties of wood cell walls depended not only on the type of the applied organosilicon but also the type of wood degradation. This means that the treatment cannot be considered universal, and specific approaches are needed for the conservation of individual wooden objects. Although some mechanisms are now better understood, such as the need for organosilicons to infiltrate the cell walls and the plasticizing effect of DEAPTMDS, other aspects will benefit from a more detailed analysis of the molecular interactions between organosilicons and wood polymers. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the changes occurring in the wood cellulose of the fast-growing poplar (Populus deltoides × maximowiczii) under the influence of steam explosion (SE) pretreatment. Cellulose from native wood and after pretreatment at 160 and 205 °C was isolated. Cellulose polymerization degree by size exclusion chromatography (SEC) and cellulose crystallinity index by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) were determined. The profiles of sugars in the native wood and in the solid fraction after pretreatment (using the acid hydrolysis method) were also determined. In addition, the profile of monosaccharides in the liquid fraction obtained after steam explosion and in the liquid fraction after acid hydrolysis of the oligosaccharides were investigated using high-performance liquid chromatography (HPLC). This allowed to determine the change in the yield of hexoses and pentoses in the studied material. The behavior of cellulose in wood subjected to steam explosion at 160 and 205 °C and isolated by the Kürschner–Hoffer method was studied by determining the absorption bands of FTIR-ATR spectra. The lateral order index (LOI) of cellulose was calculated from the ratio of the intensity of the corresponding absorption bands A1422/A896 cm−1. Total crystallinity index (TCI) of cellulose was calculated from the ratio of the intensity of absorption bands A1372/A2900 cm−1. TCI of Kürschner-Hoffer cellulose isolated from wood subjected to steam explosion at 160 and 205 °C decreased by 5.6 and 5.0%, respectively, with regard to the applied temperature. LOI increased in cellulose isolated from wood subjected to steam explosion at 160 °C (by 0.7%) and at 205 °C (by 19.2%) in relation to the index of cellulose isolated from native wood. Kürschner–Hoffer cellulose isolated from wood subjected to steam explosion at 160 and 205 °C exhibited, respectively, a reduced degree of polymerization of about 11% and about 8%. Polydispersity index in Kürschner–Hoffer cellulose was 1% lower after both pretreatments than native sample. [ABSTRACT FROM AUTHOR]

Supercritical CO2 offers an alternative method of removing wood moisture and reducing cellular collapse compared to traditional drying techniques. The technique has been previously demonstrated for Pinus radiata and Eucalyptus nitens dewatering and was modified in this study for New Zealand red beech (Nothofagus fusca) heartwood, which is notoriously difficult to dry without causing excessive distortion. The technique was also successfully extended to drying below the fibre saturation point. A specific dewatering and drying schedule was developed for N. fusca because of negligible dewatering using a schedule previously designed for wood with an open hydrofluidic network of interconnected vessels. An anatomical assessment confirmed lumen pathways were occluded with tyloses and polyphenol resins. A fluid dynamics assessment concluded that permeability measurements are recommended together with tortuosity and porosity information for improved wood species dewatering characterisation. Using the dewatering and drying schedule, collapse was successfully reduced by 92% for both normalised internal wood area and void collapse when compared to oven-dried samples. The beech specimens took 18 days to reach 17.3% moisture content (MC) but displayed some checking from early dewatering depressurisation, compared to air-dried control specimens which showed no collapse or checking but took 6 months to reach 12% MC. Supercritical CO2 dewatering and drying could be combined with extractives separation, preservative treatment, and mechanical forming of wood in one plant to make a potentially economically viable process with improved energy, environmental and carbon footprints. A techno-economic analysis is suggested to fully compare supercritical drying of wood against conventional drying operations. [ABSTRACT FROM AUTHOR]

The resin impregnation treatment of wood is used as a pretreatment to improve the deformability of wood and the durability of its formed products. The objective of this study was to clarify the effect of solvent removal after resin impregnation on wood deformation. A solution of melamine formaldehyde (MF) resin was impregnated into the wood, and the solvent was removed from the wood under vacuum or different relative humidity (RH) conditions. The deformability of MF-resin-impregnated wood was evaluated based on the load required for molding. A higher RH during solvent removal allowed the MF resin to penetrate the cell wall, while the polymerization of the MF resin impregnated in the cell lumen and cell walls was accelerated. Polymerization of the impregnated resin significantly reduced the deformability. The cell orientation and distribution of the MF resin at the cellular level in the molded products were evaluated by X-ray diffraction and Raman mapping. The results showed that the higher the RH during the solvent removal process, the higher the cell orientation and amount of resin in the cell wall. These results suggest that the solvent removal process after resin impregnation has a significant effect on deformability during deformation processing and the formed products. [ABSTRACT FROM AUTHOR]

Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) is the most important commercial timber species in the United States Pacific Northwest (US PNW). Owing to its significance, Douglas-fir has been the subject of long-term tree improvement. First-generation and second-generation progeny tests are available for wood property evaluation, but aside from specific gravity (from increment cores) and stiffness (usually determined on standing trees using acoustics), the estimation of genetic parameters has been limited. There is interest in evaluating trees for wood stiffness, but the cost of evaluation is generally a barrier. Near infrared hyperspectral imaging (NIR-HSI) may provide a rapid technique for the estimation of a variety of wood properties, providing wood property data is available for building predictive models. In this study, SilviScan was used to assess tracheid properties (wall thickness, coarseness, specific surface and radial and tangential diameter), air-dry density, microfibril angle (MFA) and stiffness for 40 calibration samples, 20 each from two progeny tests aged ten and twelve years, respectively (500 samples in all, one test site from each of two independent first-generation breeding programs). Wood properties were measured on sections of increment cores representing the five growth rings adjacent to the bark. Based on the NIR-HSI and SilviScan data from the 40 calibration samples, models were built to predict wood properties of all samples. These data were used to estimate heritabilities and trait-to-trait genetic correlations. Results from this preliminary study are encouraging and the technique can be explored on larger, multi-site, datasets. [ABSTRACT FROM AUTHOR]

Hierarchical porous carbon aerogels were synthesized from liquefied wood via physical and chemical activation processes. The morphology and structure of the KOH-treated carbon aerogel (K-LWCA) and the steam-treated carbon aerogel (H-LWCA) were systematically investigated via scanning electron microscopy, N2 adsorption–desorption tests, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Additionally, the electrochemical properties of K-LWCA and H-LWCA were evaluated via cyclic voltammetry, galvanostatic charge–discharge processes, and electrochemical impedance spectroscopy. Both H-LWCA and K-LWCA exhibited high specific surface areas (1996 and 1780 cm2 g−1, respectively) and well-developed hierarchical porous structures. Compared with H-LWCA, K-LWCA demonstrated higher specific capacitance, improved performance, and superior cyclic stability owing to its higher concentration of defects and hydrophilic functional groups. Moreover, K-LWCA exhibited an optimal mass-specific capacitance of 201.47 F g−1 at 0.5 A g−1, achieved an ideal capacitance retention of 70.15% at 20 A−1, and maintained excellent cycling stability with a retention rate of 94.11% after 5000 cycles. Furthermore, the button symmetric supercapacitor device assembled using K-LWCA demonstrated a specific capacitance of 117.78 F g−1 at 0.5 A g−1 and exhibited an energy density of 9.2 Wh kg−1 at a power density of 375 W kg−1. Therefore, this study provides a novel method for preparing biomass-derived carbon aerogel electrode materials suitable for practical supercapacitor applications. [ABSTRACT FROM AUTHOR]

Water is a universal solvent and swelling agent that is widely used in wood industry in association with organic solvents and salts, whether for the fractionation of biomass and the production of bio-based synthons for the chemical industry, the application of sizing agents and painting for the paper industry or the incorporation of preservatives to enhance wood durability for the timber industry. The relevance of solvents and technical treatments used for wood-based products requires a proper identification of the specific role of each solvent on wood biopolymers to better understand and predict their influence on wood properties. In particular, wood impregnated with aqueous solutions of organic solvents has shown to give rise to greater swelling than that observed in pure water, described as "hyperswelling". To understand this phenomenon, the first step is to examine the existing interactions between wood microstructure and the different solvents present in these mixtures. This study is an attempt to bring to light the sorption behaviour of four different hardwoods in water–ethanol vapour mixtures containing increasing molar fractions of ethanol from 0 to 100%. Contrasted sorption behaviour in pure solvents was observed according to wood species having different biochemical compositions. This behaviour highlights the different affinities of ethanol and water for the macromolecules present in the wood microstructure. With mixed solvents, peculiar effects were confirmed in sorption behaviour of woods with lower mixed solvent uptake at high partial pressures compared to pure solvents. It is also shown that part of the sorbed ethanol molecules remains chemisorbed in the wood structures at the end of the desorption process. [ABSTRACT FROM AUTHOR]

Poor dimensional stability, sensitivity to microorganisms, and flammability restrict the application of wood in certain areas where these properties are critical. Although furfurylation can improve the physical and mechanical properties of wood, the heat and smoke release of furfurylated wood during combustion are dramatic and need to be addressed. As a kind of halogen-free phosphorus flame retardant, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and its derivatives exhibit excellent performance in polymer composites. In this study, DOPO was dissolved in furfuryl alcohol (FA) and used to modify wood. The effect of DOPO on the thermal stability, combustion behavior, and physical and mechanical properties of furfurylated wood was investigated. The chemical structure, morphology, and char residue after combustion were also characterized. The studies show that DOPO can react with the FA polymer and is incorporated and homogeneously dispersed in the wood structure. Compared to untreated wood, furfurylated wood has a much higher heat and smoke release during combustion. The addition of DOPO remarkably reduces the heat release of furfurylated wood, and this effect increases as the amount of DOPO increases. When the amount of introduced DOPO of furfurylated wood is 7%, its total heat release is reduced by 37.4% and becomes comparable to the untreated wood. However, DOPO does not suppress smoke production effectively. DOPO improves the thermal stability of furfurylated wood by promoting char formation and inhibiting the diffusion of oxygen and the escape of pyrolysis products. The addition of DOPO has little effect on the physical and mechanical properties of furfurylated wood. The results indicate that the combination of DOPO and furfurylation could be an efficient way to prepare highly stable and fire-resistant wood materials. [ABSTRACT FROM AUTHOR]

Today, using one-component polyurethane (1c-PUR) adhesives in the manufacturing of engineered wood products from spruce is common practice. However, the use of other wood species can require the application of a primer to fulfill normative requirements. Previous research shows the primers' effectiveness, especially in moist environments. However, the primers' exact mode of action remains not yet fully understood. We hypothesize a reduction in the hygroscopic behavior of the primer-treated wood—intensity and kinetics—that could reduce the formation of stresses in the bond line region. To test this hypothesis, two commercially available primers, based on Polysorbate 20 and poly(ethylene glycol), and the hydroxymethylated resorcinol (HMR) primer are examined with wood from beech, birch, larch, and Douglas fir. Swelling experiments show that of each primer a portion infiltrates and swells the wood cell walls, affecting the wood's hygroscopic and mechanical properties. In stepwise sorption experiments, it is seen that the primers influence differently the amount of moisture uptaken by the wood (adsorption). The rate at which the moisture spreads within the wood (diffusivity) also changed differently for the primers, while the rate at which the moisture moves through the wood (permeability) remains unchanged. The application of all primers improves the bulk flow behavior and thus the void penetration of the adhesive into the lumina in the interphase region, which in turn leads to a reduced bond line thickness. All three primers improve the tensile shear strength. The hygroscopic changes caused by the primers appear too small to be claimed as the sole and primary cause of their functionality, whereas more relevance is seen in the primers' cell wall infiltration and the increased adhesive's void penetration. [ABSTRACT FROM AUTHOR]

In this study, we present a highly efficient and sustainable photoabsorber designed specifically for interfacial solar steam generation (ISSG) of seawater. To achieve this, we coated poplar wood with Ag-doped VO2 (Ag@VO2) and reduced graphene oxide (RGO) as single or double layers of photothermal materials. The evaporation flux of Ag@VO2 coated on poplar wood is 2.42 kg m−2 h−1, while RGO-coated poplar wood exhibited a slightly lower evaporation flux of 2.38 kg m−2 h−1. However, the evaporation flux significantly improved to 3.85 kg m−2 h−1 when poplar wood was coated with a combination of Ag@VO2 and RGO, with Ag@VO2 serving as the bottom layer and RGO as the top layer. The remarkable enhancement in ISSG performance observed in the double-layer photoabsorber (RGO/Ag@VO2/wood) is attributed to several synergistic effects. Firstly, the combination of Ag@VO2 and RGO facilitates efficient harvesting of visible and near-infrared light, enabling effective energy conversion in the ISSG process. Additionally, the surface plasmonic resonance effect exhibited by Ag further enhances light absorption. Furthermore, the low thermal conductivity and porous structure of wood, acting as a substrate, contribute to improved photoabsorber performance. Another crucial finding from our study is the stable performance exhibited by the fabricated photoabsorber. Even after undergoing 10 cycles of operation, there was no decrease in efficiency. This stability is of significant importance for practical applications, as it ensures consistent and reliable performance over time. [ABSTRACT FROM AUTHOR]

Heat treatment of wood can decrease its heat capacity and thermal transitions, which are thermal behavior properties of wood. A calorimetric study that highlights the thermal behavior of the molecular mobility of materials is necessary to investigate the thermal degradation of wood. Furthermore, combining it with a nondestructive measurement technique would widen its scope of applicability, especially for wood in service or historical wood that cannot be altered or damaged by invasive methods. Neolamarckia cadamba (Roxb.) Bosser, also known as burflower-tree, a tropical fast-growing hardwood species that has become popular for light-construction works in the past decade, is treated at 90, 120, and 150 ℃ for a duration of 8 h to 3.5 months, scheduled logarithmically. Near-infrared spectroscopy and differential scanning calorimetry (DSC) were used to measure the chemical changes and thermal behavior of the wood before and after heat treatment. Two-dimensional correlation spectroscopy (2DCOS) analysis was then applied to assess the NIR second-derivative spectra and DSC thermograms. The results showed that 2DCOS analysis could assess NIR second-derivative spectra and DSC thermograms under careful observation, as DSC thermograms comprise both qualitative and quantitative information. It provides a new point of view in the non-destructive analysis of wood thermal degradation. [ABSTRACT FROM AUTHOR]

The reversibility of a moderate thermal treatment (TT) at 120 °C on modern and historical oak wood samples was investigated by 1H nuclear magnetic resonance (NMR) relaxometry, equilibrium moisture content (EMC) determination, and measurements of volumetric deformations. The EMC values showed full reversibility after conditioning the samples at 65% relative humidity (RH) for one week, in agreement with previous research that utilized moderate TTs. However, 1H NMR relaxometry evidenced an irreversible effect on water mobility (i.e., molecular tumbling) for both wood samples. This result is compared to volumetric deformations that are determined by considering two reference states. When using, as a reference, the dry volume at each state, volumetric deformations are consistent with EMC values. However, when using the dry volume of the sample before TT, the volumetric deformations are found to be higher than the ones before TT for modern wood but remain lower for historical wood. The irreversible changes in water dynamics suggest that some modifications of the wood structure have not been completely recovered but are not linked to the changes in volumetric deformations. In addition, 13C solid-state NMR spectroscopy allowed the comparison of the composition between both wood samples, suggesting that their different behavior concerning volumetric deformations could be explained by a lower proportion of acetyl groups from hemicelluloses for historical wood due to its natural aging. We showed that combining macroscopic observations with molecular-level information gained from 1H and 13C NMR leads to a deeper understanding of the effects of thermal treatments and reversibility tests. [ABSTRACT FROM AUTHOR]

Wood-derived materials have been utilized to develop filtration membranes for sustainable oil/water separation. However, it remains a significant challenge to manufacture durable wood-based membranes with high efficiency and ultra-high flux by simple methods. Herein, we report a facile strategy to fabricate a novel superhydrophobic hybrid wood membrane (PDMS@MOF-199/WS) with ultrahigh-flux and excellent oil/water separation performance. Firstly, copper-based metal organic frameworks (MOF-199) were in situ grown on the TEMPO-oxidized wood sponge (TO-WS) substrate to construct a hierarchical micro-nano structure with internal inherent microchannels. Secondly, a super-wetting surface was formed through soaking in polydimethylsiloxane (PDMS) and heat treatment. Remarkably, the water contact angle (WCA) of PDMS@MOF-199/WS could reach 163° and the oil contact angle (OCA) was around 0°, which remained stable over a long period of ultrasonic treatment and tape peeling. More importantly, the as-prepared modified wood membrane can efficiently separate a wide range of immiscible oil/water mixtures, solely by tiny gravity, with ultra-high flux of 10,385 L m−2 h−1 (carbon tetrachloride/water) and separation efficiency of 99.6% (n-hexane). Furthermore, this novel membrane can also effectively separate surfactant-stabilized water-in-oil emulsions with an efficiency of as high as 97.8%. Meanwhile, the hybrid membrane displayed exceptional reusability, maintaining a high-flux of 8599.6 L m−2 h−1 and retaining WCA at 154.8° after 12 cycles. Our results demonstrate that the synergetic impact of MOF-199 and PDMS as a means of encoding on-surface wettability substantially improved the separation efficiency. This work opens a new avenue for the design of functional wood-derived filtration membranes for the ultrahigh flux oil–water separation. [ABSTRACT FROM AUTHOR]

Waterlogged wood conservation is a complex and challenging task. Detailed knowledge about the interactions between the applied chemicals and wood is necessary to ensure the effective and safe conservation of wooden artifacts. The present research aims to determine the mechanism of dimensional stabilization of archeological wood by organosilicon compounds using the combination of synchrotron-based X-ray fluorescence microscopy (XFM) and nanoindentation. Archeological oak wood was treated with methyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, or 1,3-bis-[(diethylamino)-3-(propoxy)propan-2-ol]-1,1,3,3-tetramethyldisiloxane, which in previous studies were found to be more effective than other organosilicons in stabilizing wood dimensions. The XFM and nanoindentation results showed that all three organosilicons infiltrated wood cell walls and enhanced their mechanical properties. The XFM also showed that part of the chemicals filled some void spaces like cell lumina. Based on the results obtained here and in our previous research, it is determined that the mechanism of archeological wood dimensional stabilization by organosilicon treatment is complex and likely involves both filling cell lumina and infiltration into cell walls where organosilicons interact with wood polymers. [ABSTRACT FROM AUTHOR]

In living spaces where wood is commonly used for both construction and decoration, it is crucial to minimize electromagnetic pollution and the risk of fire. In this study, we applied aniline treatment to wood in situ and examined its impact on electromagnetic shielding and fire resistance. By enabling in situ polymerization and the deposition of polyaniline particles within the wood, we enhanced the wood's conductivity while maintaining its porous structure, thereby improving its ability to absorb microwaves. The results indicated that wood species with low density exhibited higher electromagnetic shielding efficiency after treatment due to their greater polyaniline loading. Specifically, an specific electromagnetic shielding efficiency up to 65.8 dB cm−3 g−1 was achieved on the cross sections of treated wood. Furthermore, the total heat release and smoke production decreased by 43.9% and 66.7%, respectively, while the wood char mass increased by 66.3%. The results demonstrated that polyaniline-treated wood with bifunctional features could serve as a promising candidate in this field. [ABSTRACT FROM AUTHOR]

The effects of different microwave energy densities (0, 60, 80, and 100 kWh/m3) on the gas permeability of sapwood and heartwood of radiata pine in the longitudinal, radial, and tangential directions were investigated. The multi-scale pore size distribution was systematically analyzed with various analytical methods. High intensity microwave (HIMW) treatment significantly improved the gas permeability of the wood in three directions, and the gas permeability was positively correlated with the microwave energy density. The gas permeability of the treated sapwood was 1.6–2.5 times higher, and that of the treated heartwood was more than 6 times higher than the untreated wood at the microwave energy density of 100 kWh/m3. The HIMW treatment significantly affected the pore size distribution. In the micropore–mesopore (< 50 nm) range, the surface area and average pore diameter of the treated sapwood samples were 10.68% and 17.12% higher, respectively, and the total pore volume was 31.50% lower than that of the untreated sample. However, the specific surface area and total pore volume of the heartwood samples were 14.92% and 26.06% lower, respectively, and the average pore diameter was 35.55% higher at the microwave energy density of 100 kWh/m3. Treated wood mainly had slit-shaped mesopores (< 10 nm). For macropores (> 50 nm), treated sapwood displayed 20.57% total pore volume increase and 11.66% porosity rise; treated heartwood showed 31.24% total pore volume rise and 20.78% porosity increment. Furthermore, SEM results showed HIMW treatment damaged weak structures like the compound middle lamella and ray parenchyma cells. [ABSTRACT FROM AUTHOR]

Surface carbonization, or charring, of wooden exterior cladding boards is a modification method that creates a fully organic barrier layer in resemblance to a coating. The process effectively degrades the wood and transforms it into a carbonaceous residue that protects the underlying unmodified wood from environmental stresses. The surface quality of wood modified in this manner is a combination of several factors and depends on the manufacturing method and wood species. To assess the quality of spruce and birch modified with contact and flame charring techniques, several experiments were set up from the nanoscale to macroscopic evaluation of surface resistance to different stresses. The changes in elemental composition are scaled with the modification severity with little differences between wood species. The carbon structures analyzed by high-resolution transmission electron microscopy (HR-TEM) were found to be amorphous, but the electron energy-loss spectroscopy (EELS) revealed higher ordering with what is assumed to be random graphitic stacking of carbon sheets. These carbon–carbon bonds are stable, so a higher ordering is hypothesized to induce improved resistance to exterior stresses. The scanning electron microscopy (SEM) revealed a clear difference between contact-charred and flame-charred woods. The selected contact charring temperature was not high enough to induce the transformation of cell walls from anisotropic into an isotropic material but provided other benefits such as a relatively crack-free, smooth and scratch resistant surface. Surface roughness was able to adequately predict the surface quality of the contact-charred samples, and scratch tests were found to be suitable for evaluating the mechanical stress resistance of the surface instead of abrasion. In terms of overall quality, birch instead of spruce was concluded to better respond to both charring methods, although contact charring eliminates some species-specific characteristics, resulting in more homogeneous surfaces. [ABSTRACT FROM AUTHOR]

This research has demonstrated that SiO2 impregnation under high vacuum pressure of − 90 kPa can significantly reduce porosity by almost 10%, and improve the mechanical and viscoelastic properties of spruce wood under dry and saturated states. Characterization methods, such as impact test, DMA, SEM, EDS, porosity and SAXS tests were conducted on non-treated and − 90 kPa treated spruce wood samples under dry, saturated and submerged states to analyze the synergistic effect of high vacuum SiO2 impregnation pressure on wood properties. The results showed that high vacuum impregnation pressure had a significant positive reinforcing effect on wood's properties. It increased the impact resistance of wood under dry and saturated conditions. Additionally, the high vacuum impregnation technique was able to overcome the water-induced softening effect and caused a significant increase in the storage modulus through uniform dispersion of the SiO2 particles in the wood's vascular structure. Consequently, the impregnation reinforced the wood and ameliorated its capacity to absorb energy. High vacuum impregnation was also able to counteract the plasticizing effect of the water molecules and significantly increased the loss modulus by increasing the internal friction and cohesion of the wood components with the addition of the nanoparticles to the vascular system, which increased the wood's capacity to transform and dissipate energy. Quantitatively and qualitatively, impregnation under a vacuum pressure of − 90 kPa exhibited an effective obstruction of the vascular structure of spruce wood. In all conditions, high vacuum-impregnated samples showed significant enhancements over non-treated samples. This research demonstrated that high vacuum SiO2 impregnation is an effective wood processing technique. Multiple materials and applications could benefit from this research wherein high strain-rate deformations are expected to occur or when simultaneous elastic behaviour of wood and its damping energy is needed. This study could also pave the way for research on the synergistic effect of SiO2 impregnation and water absorption on the viscoelastic behaviour of wood. [ABSTRACT FROM AUTHOR]

Internal moisture distribution seriously affects timber shrinkage relations during drying, and it is also an essential parameter for testing the validity of a three-dimensional heat and mass transfer model. Here, we present an experimental study of 3D changes in moisture content at different stages during constant temperature and humidity drying of two wood species, covering visible moisture movement evaporation surface, 2D and 3D moisture variations, moisture values in the dry and wet zones, and color changes. We show that the evaporating surface was a wet front, its influence on the wood 3D structure is in the tangential > radial > longitudinal direction, and the color difference ranges from 10.6 to 17.6 when the wet front is present. Moisture values for poplar and pine at the disappearance of the wet front ranged from 14.2–19.7% to 20.4–22.5%, respectively. In mass transfer during wood drying, wood dimensional simplification and homogenization in the drying model should not be used, and the moisture content in each wood thickness layer should be evaluated in a diversified manner. [ABSTRACT FROM AUTHOR]

Pyrolysis is an oxygen-free process for the thermal decomposition of raw materials. The heat conduction and flow of pyrolysis products (i.e., the gas fraction and liquid vapour generated during pyrolysis) influence the process and products. In this work, the influence of the orientation of wooden particle fibres with respect to the direction of the heat source on the dynamics of the process was investigated, where there were two particle sizes oriented along or across the heat source. The novelty of this work lies in the use of a radiographic technique for analysing the influence of wooden fibres' orientation on the degradation process. The research showed that during pyrolysis, the mass loss rate in the particles with fibres oriented across the heat source and along the heat source was different. A similar tendency was characteristic for the drying process. The dynamics of pyrolysis of a single wood particle depends on many factors—particle size, process parameters, arrangement of fibres in wood, etc. The analysis of the dynamics presented in the publications is based on the analysis of the dynamics of mass loss, which is a very large simplification. The publication contains experimental analysis and mathematical calculations of the pyrolysis process for samples of various sizes and samples with different fibre arrangement. The result of the research is the determination of trends regarding the shape of the particle and the arrangement of fibres on the process, which provides knowledge that can be translated into industrial pyrolysis processes. [ABSTRACT FROM AUTHOR]

Driven by the quest for greener and more sustainable materials, the presented review analyzes recent studies in which wood and wood-based materials were combined with carbon nanomaterials in the form of carbon nanotubes and graphene. The analysis shows a close kinship between these two carbon-based materials. The first studies have shown that wood may be directly transformed into sp2-bonded carbons, i.e., form graphene-like structures. Further, it has been demonstrated that both carbon nanotubes and graphene can be used to coat or infiltrate wood and processed wood-based materials such as flexible wood sponges or biochars. Thanks to the unique electrical, mechanical, thermal, and wetting properties of graphene and carbon nanotubes, their wood-based nanocomposites were shown to have many potential applications in green electronics area or as nanodevices. Finally, a new range of studies in the area of wood composites showed that carbon nanomaterials integrated into wood-based boards could improve the properties of the former ones. The presented review shows that this emerging area of research on wood-based materials, graphene, and carbon nanotubes is highly promising and interesting in the context of new applications and future perspectives for sustainable development. [ABSTRACT FROM AUTHOR]

Combining spatially localized X-ray diffraction (XRD) with X-ray microtomography (XMT) enables the mapping of the micro- and nanoscale structures simultaneously. The combination of these methods results in a powerful tool when considering the structural studies of hierarchical materials, allowing one to couple the relationships and connections of the structures at various scales. In this study, XMT was used to map the anatomy and cellular structures in 3D in tension and opposite wood with 1.5 µm resolution, while XRD was used to determine the cellulose crystallite widths and microfibril orientations with 100 µm spatial resolution within the same tissues. Tension wood (TW) has an important biological function with clearly distinct properties to opposite (OW) and normal wood, e.g. differing cellular structures with a higher cellulose content. This is the first study of very young hybrid aspen saplings (1-month-old) using the combined diffraction tomography method. The TW tissues could be identified from the OW tissues based on both the XMT and XRD results: TW had a higher average size of the cellulose crystallites and smaller mean microfibril angles (mMFA) than those in OW. With the XRD data, we were able to reconstruct the images of the cross sections of the saplings using the structural parameters (cellulose crystallite width and mMFA) as contrast mechanisms. As far as the authors know, there are no previous studies with images on any TW samples using the XRD-based contrast. Home laboratory bench-top set-up offers its advantages for these studies, considering the number of samples characterized, time-dependent studies and larger field of views. [ABSTRACT FROM AUTHOR]

This paper deals with the optical observation and evaluation of the swelling of beech wood samples (Fagus sylvatica L.) during gaseous ammonia treatment. The pressure level was varied in several experiments from ambient pressure to almost saturated steam pressure at isothermal conditions at 20 °C. The initial moisture content of the wood was oven dried and also conditioned (65% RH/20 °C). All experiments were carried out in a self-developed experimental setup. It consisted of three parts: a pressure vessel with a glass pane at the top, a camera with additional lighting above it and an algorithm for the semi-automatic evaluation of the data. Parallel investigation of the maximum swelling in water of specimens of the same origin showed that ammonia leads to a higher swelling in tangential direction (up to 23%). The swell-inhibiting influence by the wood rays can be observed on the basis of the comparison to the water swelling in radial direction. Furthermore, the results visualise the change in crystal structure from cellulose I to ammonia-cellulose I. [ABSTRACT FROM AUTHOR]

The aging process, although not mandatory in the production of cachaça, adds sensory complexity to the beverage. During the aging process, several physicochemical reactions occur between the wood and the distillate, such as hydrolysis, oxidation, polymerization, and esterification. The phenolic compounds related to maturation, extracted from the wood, directly interfere in the chemical and sensory composition of the distillate. However, knowledge of wood composition is not enough to determine the sensory profile of cachaça, since this also depends on numerous factors such as the origin of the wood, wood species, barrel manufacturing, number of times the barrel was used, aging time, and composition of the beverage. This research explores, quantitatively and qualitatively, the influence of these factors on the extraction of phenolic compounds derived from lignin in cachaça aged up to 144 months in oak barrels of different origins using high-performance liquid chromatography. The content of phenolic compounds increased at an accelerated rate in the first years of aging. Nonetheless, the wood species and the number of times the barrels were used exhibited great influence on the evolution of aging, regardless of the aging time. Regarding the extraction of maturation indicators, each year of aging in new barrels corresponded to approximately 5 years of aging in extensively used barrels. [ABSTRACT FROM AUTHOR]

Understanding wood cell wall pore geometry and distribution is the basis for studying its macroscopic properties. This research investigated the pore fractal dimension using the pore size distribution of selected softwoods and hardwoods. Nitrogen gas analyzer was used to study the detailed structural parameters of wood pore size distributions and use as a raw data to assess their fractal dimension. The results revealed significant variability in pore size distribution, porosity, pore volume, specific surface area, and fractal dimension. The cell wall pore size distribution ranged from 1.41 (minimum) to 442 nm (maximum). Western red cedar heartwood and sapwood show a higher and lower number of micropores, respectively, in the wood cell wall. The results also showed that the fractal dimensions of the cell wall pore spaces of wood vary between 2.92 and 2.97. There was no significant difference in fractal dimensions between wood types and species. [ABSTRACT FROM AUTHOR]

Hygroscopic properties of wood have been utilized in adaptive façades to respond to variation in humidity levels. Shape-shifting materials have been developed to replace mechanical actuators that respond to climatic variation with zero-energy consumption. This paper presents a systematic review of the literature on the use of hygromorphic behaviour in developing adaptive architectural façades, with the primary focus of identifying the venues of implementation of hygroscopic actuation in adaptive facades. The paper triangulates the intersection between hygroscopic design parameters with manufacturing strategies and their application as a passive motion mechanism in adaptive facades. This review focuses on state-of-the-art experimental work in hygroscopic design, with specific interest in manufacturing methods of hygromorphic adaptive façades, response motion behaviour evaluation and tracking, analysis of the current applications of hygromorphic design in real weather conditions, and performance prediction. Results reveal that most of the studied papers focus on the response behaviour of programmable materials to variation in moisture content and the implementation of hygroscopic design in adaptive façades. From the literature analysis, it was shown that programming the response behaviour of hygroscopic materials mainly takes place through variation in fabrication methods, followed by passive layer configurations, which act as actuators that are controlled by differences in layer properties. [ABSTRACT FROM AUTHOR]

A novel, environmentally friendly, biomass-based modification technique utilizing carboxymethylation-activated alkali lignin (CAAL) and glutaraldehyde (GA) is proposed to enhance the physical and mechanical properties of poplar and fir wood. Water-soluble CAAL was prepared by modifying alkali lignin (AL) with sodium chloroacetate following low-temperature activation under a NaOH/urea system. AL is a biomass-based material from industrial by-products. As such, it does not rely on fossil resources nor emit volatile compounds that might limit its range of application. The successful preparation of CAAL was demonstrated by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (NMR), and 13C NMR, and the changes in structure were analyzed by 2D-heteronuclear singular quantum correlation (2D-HSQC), 31P NMR, and gel permeation chromatography (GPC). The following characteristics of the modified wood samples were investigated in detail: weight percent gain (WPG), bulking, anti-swelling efficiency (ASE), water absorption rate (WAR), leachability of the modifier, microstructure, and mechanical properties. Water immersion results demonstrated that the CAAL/GA hybrid modifier enhanced ASE to 41.3% and 31.5% for fir and poplar, respectively, at a concentration of 15 wt.%. Furthermore, the WAR of fir was reduced by nearly three times to 30.7%, compared to that of a control sample treated solely with GA. GA-treated samples showed high brittleness, whereas both poplar and fir showed enhanced modulus of rupture and elasticity following treatment with the CAAL/GA hybrid modifier. [ABSTRACT FROM AUTHOR]

The Jingtoushan Site (8300–7800 BP), located in Ningbo City, Zhejiang Province, is of great value for the in-depth understanding of China's prehistoric coastal culture. At this site, numerous valuable wooden relics showing past human civilization have been discovered. Multiple approaches were taken, including wood anatomy and physicochemical analyses, to assess the preservation state of waterlogged archaeological woods (WAWs), while using high-throughput sequencing (HTS) to explore their microbial diversity and composition as well as that of the surrounding soil. The secondary walls of WAWs showed to be severely degraded, whereas the compound middle layer and cell corner were well preserved. Bacteria were the main microorganisms causing the biodegradation of WAWs, and 85.6% of the phyla was also found in the surrounding soil environment. Specifically, Arcobacter, Flavobacterium, Hyphomicrobium, Pseudomonas and Sphingomonas, bacteria retrieved by HTS in high abundance, were inferred to be potentially associated with the biodegradation of WAWs at the Jingtoushan Site. Meanwhile, it is hypothesized that lignin in the wooden artefacts still buried and unexcavated at the Site might be at risk of further degradation, although it may be better preserved than the cellulose and hemicellulose. [ABSTRACT FROM AUTHOR]

This study proposed a new method for the rapid and uniform removal of lignin components from wood, which was applied to abundant fast-growing Chinese fir. Based on the lignin removal using acidic NaClO2, the impregnation process with positive pressure-negative pressure circulation was used to promote the reaction. Using this method, the time of the impregnation and discharge of lignin was shortened, and the complete cellulose skeleton of Chinese fir can be easily prepared. The lignin removal effect on crystalline structure and chemical structure was discussed. It was deduced that the macroscopic morphology of Chinese fir was complete and the end face did not crack under the positive–negative pressure cycles. The FTIR showed that the proposed method can better reduce the damage of holocellulose by delignification treatment and uniform and efficient removal of lignin. The relative crystallinity gradually increased with the increase in the cycle number, achieving a selective delignification effect. This method achieved accurate regulation of the lignin removal effect, promoted the utilization of Chinese fir in functional materials, and provided a cellulose wood-based template for the high-value utilization of Chinese fir. [ABSTRACT FROM AUTHOR]

In this study, metal-free wood-based encapsulating materials for white light-emitting diode were obtained by using renewable transparent wood as the biological support and the light scattering component, and graphite carbon nitride as the color light emitting component. The graphite phase carbon nitrides with blue and green color were prepared by thermal polymerization through structural regulation of raw materials. The resulting different color phosphors were mixed with epoxy resin, respectively, and then, blue epoxy resin, green epoxy resin and red epoxy resin were mixed with a mass ratio of 4:2:1 and a proper amount of curing agent. The delignified balsa wood with high porosity was vacuum impregnated with epoxy resin mixture to obtain white luminescent transparent wood with better performance such as high transmittance and high haze. This work provides a feasible solution for the sustainable development of transparent wood and the application of transparent wood to photoelectric materials. [ABSTRACT FROM AUTHOR]

Biomorphic TiO2 with hierarchical porous structures for photocatalytic degradation is fabricated by templating wood residues of different size scales (lignocellulose, wood flour, and solid wood as biological templates) using a simple sol–gel method. Compared to template-free TiO2, the biomorphic TiO2 had a better adsorption capacity and photocatalytic performance when decomposing methylene blue (MB) and phenol. The lignocellulose-templated TiO2 reached adsorption equilibrium within 60 min because of a composite hierarchical structure with the complex interlaced wood, and demonstrated 98.9 and 84.3% degradation of MB and phenol within 60 min under visible light conditions. The multiscale structures of these wood templates enhanced light absorption and mass transfer efficiency due to the presence of additional surface hydroxyl groups and a reduced bandgap. This research proposes a convenient synthesis method to obtain biomorphic TiO2 using wood residues and modifies the physio-chemical interaction between wood and TiO2 to enhance the visible light response and transfer of photogenerated charge carriers in the system. [ABSTRACT FROM AUTHOR]

Nano-particles have attractive properties that may extend the protection periods for traditional coating systems against ultra-violet light degradation, but the direct role of nano-particles in UV performance remains poorly defined. The effects of UV light on relationships between nano-particles and radiata pine (Pinus radiata) sapwood samples were investigated using Fourier Transform Infrared spectroscopy to detect surface chemistry changes before and after 8 weeks of outdoor exposure. Color changes were characterized by measuring CIE L*a*b* parameters on specimens treated with water dispersions of α/γ-iron oxide (Fe2O3) or zinc oxide (ZnO) and exposed to sub-tropical conditions out of soil contact. Alpha Fe2O3 provided the most effective protection of wood from photo-discoloration especially at higher concentrations. Nano-particles exhibited limited interactions with the wood surface before exposure. All types of nano-particles examined were associated with reductions in the vibration of carbohydrate functional groups, while γ Fe2O3 and ZnO nano-particles increased the aromatic skeletal vibration in lignin. Although none of the selected nano-particles completely protected wood from UV damage, α Fe2O3 nano-particles provided some lignin protection with the primary lignin peak at 1509 cm−1 remaining after weathering. Both types of iron oxide provided similar UV protection to cellulose and hemicellulose. While ZnO nano-particles failed to prevent lignin degradation during UV exposure, they provided some cellulose protection as evidenced by the significant increases in cellulose-associated peaks. The results suggest that combinations of zinc and iron oxide nano-particles might be useful for UV protection. Further trials are underway studying mechanisms by which these systems function on wood surfaces. [ABSTRACT FROM AUTHOR]

Catalpabungei is an economically important native hardwood in China whose hygroscopic behavior is vital for industrial applications as it influences the final product's dimensional stability and mechanical properties. In this study, the adsorption and desorption behavior of earlywood and latewood in the same growth ring of C. bungei wood samples was documented using a dynamic vapor sorption resolution and analyzed using the Guggenheim–Andersen–de Boer (GAB) model. The earlywood and latewood exhibited varying sorption isotherms and hysteresis degrees, and the reasons were analyzed in terms of structure and chemical composition (mainly hemicellulose and lignin). The influence of benzene–alcohol extracts and vessels on sorption characteristics was also examined. The GAB model perfectly fits the experimental data (R2 ≥ 99.7%) over the full relative humidity range. Specifically, parameters such as the internal specific surface area of wood can be obtained from the GAB model to help explain the differences in sorption properties between earlywood and latewood. The maximum water content bound to the primary sites for earlywood and latewood is 6.87% and 7.47%, respectively. Correspondingly, two internal specific surface areas are 261 m2/g and 284 m2/g, respectively. The adsorption isotherms of earlywood and latewood in C. bungei cannot be fully classified as type II. [ABSTRACT FROM AUTHOR]

Controls over the dimensions of waterlogged archaeological wood (WAW) upon drying are a critical issue for its conservation. Surface-initiated activator regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP) has been proven to be an effective consolidation method to increase the dimensional stability. However, the drawback of the current method is that the expansion stress generated during graft polymerization cannot be well controlled. An improved SI-ARGET ATRP system using a bifunctional monomer ethylene glycol dimethacrylate (EGDMA) to introduce a cross-linking process during the polymerization is presented in this paper. Both Pinus massoniana and Sapium sp. samples with different maximum moisture contents as 507% and 863%, respectively, show a reduced volumetric shrinkage of around 5% without any expansion phenomenon after the treatment. This method shows potential applications in the field of WAW conservation and may provide a new solution for consolidation of other organic archaeological objects as well as developing new wood-based materials. [ABSTRACT FROM AUTHOR]

Wood is an abundant, sustainable, low-carbon emission engineering material. However, fire safety issues and insufficient mechanical strength limit its applications. Herein, a simple and scalable method is developed to prepare a robust and flame-retardant structural wood that endures high-temperature flame attack. Natural wood undergoes partial delignification, flame-retardant modification, and densification to obtain ammonium dihydrogen phosphate (ADP)-densified wood. ADP is uniformly impregnated to the wood cell walls to form P–O–C bonds with a dense and cross-linked structure. ADP-densified wood presents enhanced thermal stability, flame retardancy, and mechanical robustness. Its mechanical performance is well-preserved from high-temperature flame heating. In particular, its tensile strength and flexural strength are 22.6-fold and 17.8-fold higher than natural wood after being heated for 300 s. The improved performance is due to the synergistic effect of ADP flame retardant, which accelerates the insulating char formation, and the dense and cross-linked wood structure, which leads to the condensed and robust char structure. The insulating and condensed char limit the heat and pyrolyzed combustible gases transfer between the wood surface and the interior, which protects the wood interior from high-temperature flame heating. ADP-densified wood, as a robust and flame-retardant structural material, has great potential in green and energy-saving construction applications. [ABSTRACT FROM AUTHOR]