Wood Science and Technology最新文献

In this study we separated the chemical components of cork from Quercus variabilis by various solvent extraction and alcoholysis methods. We identified the content and chemical composition of suberin and dichloromethane extract with gas chromatography-mass spectrometry (GC-MS) and analyzed the antifungal effects of different cork extracts against wood-decaying fungi. The results showed that the main structural component of cork, suberin, averaging 36.34% of the total dry weight, exhibited a pronounced inhibitory effect on wood-decaying fungi, compared to the dichloromethane extract. By the end of the entire culture period, the colony diameter of white rot fungi was 5 mm in the 40 mg/mL suberin treatment group, 19 mm for brown rot fungi, both significantly smaller than the control group (90 mm). Hydroxy fatty acids, free fatty acids, and α,ω-diacids may be the key components contributing to the antifungal activity of suberin. The inhibitory mechanism of suberin components on wood-decaying fungi may involve suppressing the respiratory metabolism of the fungi and increasing the permeability of their cell membranes, thereby limiting their normal life activities.

As one of the most common tree species, birch wood (Betula pendula Roth) is widely used as a material of furniture and decoration indoors for its many excellent characteristics. Whereas there are some studies on the volatile composition of the essential oil from the leaves of Betula pendula Roth, only limited information is available on the odor-active constituents of birch wood. To close this gap, the odorants of birch wood were investigated by means of instrumental and sensory analyses, including techniques such as gas chromatography-flame ionization detection/olfactometry, high-resolution gas chromatography-mass spectrometry, and heart-cut two-dimensional high-resolution gas chromatography-mass spectrometry/olfactometry. Overall, a total of 20 odorants was (tentatively) identified on the basis of their respective odor qualities and retention indices and mass spectra by comparison with reference compounds. It was shown that birch wood odor is dominated by a series of terpenes, terpenoids and phenyl compounds originating from the degradation of lignin and aldehydes, ketones and acids originating from fatty acid degradation. By a sensory evaluation of the birch wood, the predominant odor attributes were determined to be earthy, pencil-like, corky/mouldy, grassy, fatty, fruity, green tea-like, herb-like, vanilla-like, and vinegar-like.

The mechanical properties of structural timber largely depend on the occurrence of knots and on fibre deviation in their vicinities. In recent strength grading machines, lasers and cameras are used to detect surface characteristics such as the size and position of knots and local fibre orientation. Since laser dot scanning only gives reliable information about the fibre orientation in the plane of board surfaces, simple assumptions are usually made to define the inner fibre orientation to model timber boards. Those models would be improved by better insight into real fibre deviation around knots. In the present work, a laboratory method is developed to evaluate growth layers geometries and fibre orientation, solely based on the fact that the fibers are parallel to the tree rings and without any further assumptions. The method simply relies on color scans and laser dot scans of Douglas fir (Pseudotsuga menziesii) timber specimen sections revealed by successive planing. The proposed method provides data on fibre orientation in 3D with an accuracy that is relevant for the calibration of detailed models.

The objective of this study was to produce hydrophobic porous wood ceramics as adsorbents for CO₂ through the resin treatment of pine. The prepared samples underwent analysis using various methods to determine their structure and properties. An orthogonal experimental approach was employed to obtain adsorbents with optimal preparation process. The highest adsorption capacity was determined to be 1.36 mmol/g at a temperature of 30 ℃ and a CO₂ concentration of 15 vol%. The effect of temperature on the microstructure of wood ceramics was studied by characterization. Increasing temperatures adversely affected the adsorption capacity. Nevertheless, the hydrophobic nature of wood ceramics resulted in little impact of humidity on CO₂ absorption. The CO₂ adsorption kinetics of wood ceramics were analyzed using kinetic studies, which demonstrated that the kinetics can be accurately fitted by both the pseudo-first-order and Avrami models. The findings of the adsorption isotherm analysis showed that the Langmuir model fit was optimal. Following 30 cycles of adsorption-desorption in the presence of simulated gas, the CO₂ sorption capacity of the wood ceramics was maintained at over 90%. In terms of CO₂/N₂ selectivity, the wood ceramics showed a clear preference for CO₂, especially at 30 °C, where the CO₂/N₂ selectivity ratio reached 24.50.

Lignin fluorescence in plant cell walls significantly interferes with Raman spectroscopic signals, resulting in compromised analytical accuracy and resolution. To address this issue, a strategy was implemented to both reduce the absolute lignin content in samples and prepare thinner plant tissue sections. This approach involved embedding plant samples in LR White resin, complemented by an ultrathin sectioning technique. Additionally, algorithms were developed to eliminate the impact of resin spectra on the imaging process. These advancements collectively enhanced the performance of Raman spectroscopy by effectively diminishing the disruptive effects of lignin fluorescence. Further analysis with confocal laser scanning microscopy (CLSM) elucidated the presence of aggregation-induced luminescence (AIE) in plant tissues, revealing a direct correlation with lignin concentration. These findings not only offer a new perspective for the application of Raman spectroscopy in plant science, but also pave the way for advancements in tip-enhanced Raman spectroscopy (TERS) detection.

The development of multifunctional electromagnetic interference (EMI) shielding materials with low cost, stable performance and mass production is still facing great challenges. High-density traditional metals limit the application of EMI shielding materials. The unique structure of wood is considered an effective way to solve the above-mentioned problems. In this study, waste wood was used as raw material to prepare low-energy metallized particleboard. The particleboard was functionally finished to show excellent hydrophobic properties and been used stably in a humid environment. Dynamic thermal mechanical properties and mechanical properties analyses of particleboard were carried out. The bend strength (MOR), elastic modulus (MOE) and tensile strength were 30.50 MPa, 5384 MPa and 7.85 MPa, respectively. Metallized particleboard exhibited excellent electromagnetic shielding effectiveness (EMI SE) (average value 81.62 dB) in the entire X-band. The preparation of wood-based shielding metallized particleboard provides a feasible strategy for replacing traditional metal materials.

This study proposed a linear model between internal bond strength and compressive elastic modulus based on Griffith’s fracture theory. The local compressive elastic modulus was determined by non-destructively detecting the inherent frequency of material vibration using a method based on rod longitudinal vibration theory. In the experiment, the inherent vibration frequencies of 10 types of medium-density fiberboard (MDF) were measured through excitation and vibration of piezoelectric ceramics based on longitudinal wave vibration theory. Then, the compressive elastic modulus of each board was calculated. The calculated compressive elastic modulus of MDF and the measured internal bond strength values were fitted into a linear regression model. A high linear correlation between them (r² = 0.972) was found, having a mean square error of (2.6times {10}^{-5}). In addition, the average error between the model prediction value and the measured value was 0.014 MPa, having an average relative error of 1.49%. The maximum error was 0.044 MPa with a maximum relative error of 5.06%, indicating that the developed model was highly consistent with reality and had very small deviations. The results indicated that this proposed method can be used to accurately estimate the internal bond strength by non-destructively detecting the compressive elastic modulus of MDF.

In this study, we have implemented the first lattice model that incorporates progressive material damage, taking into account ductile failure under compression and brittle failure under tension. The model also considers fracture energy within the constitutive model by incorporating progressive material degradation, where damage variables depend on the fracture energy of the material. In addition, the lattice fracture criterion includes a typical failure criterion for wood and assumes a coefficient of variation in elastic constants and strengths to account for the heterogeneity of wood. The lattice model relies on axial springs, with their mechanical properties explicitly calculated based on the wood’s macroscopic mechanical properties. The model’s capability is evidenced by simulating two fracture tests and comparing the results with previously presented numerical and experimental data. The observed results align well with experimental observations.

The paper production industry annually produces approximately 50 million tons of lignin, an intermediate product. While lignin has the potential for producing valuable chemicals and energy materials, an effective method for its conversion is yet to be developed. This study aims to establish a sustainable and environmentally friendly approach for electrochemically synthesizing valuable compounds from lignin with using natural deep eutectic solvents as electrolytes. The study used cyclic voltammetry (CV) for the electrochemical depolymerization of Kraft lignin, examining the effects of different scan numbers on depolymerization and the resulting lignin derivatives. Observed changes in the depolymerization peak current of lignin were reported as the number of scans increased. Choline chloride: Lactic acid (CC:LA), Choline chloride: Ethylene glycol (CC:EG), and Lactic acid:1,2-propanediol (LA:PR) were used as green electrolytes. Syringaldehyde was found to be the major compound obtained by this method. As a result of statistical analysis performed using The Grey Relations Analysis method, it was determined that the conditions that utilized Kraft lignin with the highest added value involved performing five cycles of CV scans with the CC:LA electrolyte. CV scans in DES environments increased the yield of lignin-derived phenolic compounds.

Water has different forms of existence in wood (free water and bound water), which can generate different effects on the microstructure of wood. Compared to other methods, the freeze-thawing method is equipped with simple, environmentally friendly, and low-cost features. In this paper, the permeability of wood with different ratios of free water to bound water (water content), as well as the pore structure characteristics and electrochemical properties after carbonization, were investigated by the freeze–thaw method. The results show that dry samples of poplar chips with a moisture content of 15–17% after KMnO₄ and freeze–thaw cycle treatment and carbonization (PC@15%-MnO) have a specific surface area of 936.94 m²/g. The areal specific capacitance is 4784 mF/cm² at a current density of 12 mA/cm², which is 3.3 and 22 times higher than those of wood-derived carbon without freeze–thaw treatment, respectively. Additionally, PC@15%-MnO maintains 80% of its specific capacitance after 2000 testing cycles, indicating that the freeze–thaw method effectively enhances the permeability, pore structure, and electrochemical properties of wood-derived carbon materials. This strategy offers new avenues for the research and application of wood in electrode materials.