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The fungus Physisporinus vitreus and the bacterium Bacillus subtilis are commonly used organisms in wood biotechnology to increase wood permeability. However, comparative researches on wood destruction by these biological wood decomposers are scarce, particularly from microscopic and chemical perspectives. This study aimed to compare the fungal and bacterial wood destruction patterns over time. Loblolly pine (Pinus taeda L.) heartwood samples were exposed to both organisms for six and nine weeks; microscopic and spectroscopic analyses of the incubated wood were performed, and mass loss of samples was calculated. Both organisms initially destroyed the pit tori and ray parenchyma cells, but B. subtilis was more selective in its consumption of wood components. It exclusively consumed hemicelluloses and free carbohydrates in wood, whereas the fungus destroyed all chemical components simultaneously. The digestion of bordered pits by B. subtilis was more selective than that by P. vitreus, making it a better choice for controlled wood destruction. By extending the exposure duration, the bacterial destruction pattern remained consistent, whereas fungal destruction spread to the secondary wall of the tracheids. Understanding the interactions between microbes and wood can lead to a more effective and efficient use of this natural resource. [ABSTRACT FROM AUTHOR]

Background and objectives: Surface modification and coating is one of the effective methods to increase the performance and service life of wooden structures. All kinds of super-hydrophobic techniques with the contact angle above 150 degrees and a sliding angle less than 10 degrees, in addition to creating high hydrophobicity, also improve the antimicrobial and other surface properties of the substrate. Nevertheless, resistance to mechanical and moisture damage are very important in connection with super-hydrophobic surfaces. Natural waxes are one of the efficient and healthy materials for creating a durable super-hydrophobic coating with high biocompatibility. In this research, nano-silica modified with non-fluorine alkyl materials in the presence of epoxy resin has been used to create super-hydrophobic surfaces of birch wood (Betula pendula). Also, carnauba wax has been used to improve water repellency, self-cleaning property and durability in conditions of mechanical damage, humidity and harsh environments, comparatively. Materials and methods: Dodecyltrichlorosilane was used in the presence of toluene solvent for functionalizing and hydrophobicizing silica nanoparticles. A formulation containing 2% of modified nano silica and some epoxy resin was used by spray method to fabricate superhydrophobic coating on birch wood. Also, the optimal amount of vegetable carnauba wax (Brazilian palm) was used as a reinforcing agent to make the nanohybrid formulation. Durability and stability to mechanical damage (sandpaper abrasion, water impact) and harsh environments (acidic, alkaline, ultraviolet rays and solvents) were investigated. Finally, the self-cleaning potential of the processed wooden surfaces was evaluated by qualitative (inclined surface) and quantitative (dropping) methods using edible liquids. Results: Both types of nanocomposite (without wax) and nanohybrid (containing wax) coatings caused the super-hydrophobicity on birch wood. The adding the optimal amount of carnauba wax to the epoxy-based nanocoating structure leads to a contact angle of 170 degrees and a sliding angle of less than 3 degrees by water drops. In addition, carnauba wax caused the stability and strength of super-hydrophobic surfaces in aging and mechanical conditions. The highest level of stability in harsh environments was related to the hybrid nanocoating. The highest contact angle was observed for pomegranate juice and the lowest for milk. Also, the self-cleaning potential with various types of Fanta and Coca-Cola drinks on the super-hydrophobic surface was successful. Conclusion: The use of carnauba wax increased the contact angle and decreased the sliding angle. The use of carnauba wax significantly improved the mechanical properties and waterrepellency of the super-hydrophobic coating. The chemical nature and morphological structure of wax in the coating is the reason for this superiority. The super-hydrophobic surface made with nanohybrid coating in the presence of carnauba wax has the potential of self-cleaning, biocompatibility and stability in service conditions and can be used to protect all types of general surfaces in the field of food, especially lignocellulosic substrates such as wood and paper. [ABSTRACT FROM AUTHOR]

Due to the use of heat-treated wood products like ThermoWood®, even for indoor applications, the type and amount of volatile organic compounds (VOCs) emitted from the products are essential for indoor air quality and human health. The drying method of wood applied as the first step in the ThermoWood® production process may influence this property. In this study, the effects of radiofrequency/vacuum (RF/V) drying technology in comparison with conventional kiln drying at a mild and normal temperature on the emission of VOCs from Scots pine ThermoWood® were investigated using Headspace Gas Chromatography-Mass spectrometry (HS-GC-MS) and olfactory system (electronic nose). An olfactory machine consisting of 6 metal oxide semiconductors (MOS) sensors were used for this purpose. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were applied to classify and analyze the data of olfactory signals. Results showed that emission of VOCs was higher in the samples dried by RF/V technology and was mainly consisted of terpenes, aldehydes, and alcohols. Acids were identified as the main VOCs in the ThermoWood® produced from RF/V dried wood. The emission of some VOCs, such as terpenes, was reduced after thermal modification. Overall, it can be concluded that the type and the amount of VOCs of ThermoWood® are influenced by the drying method of wood applied before starting the thermal modification. [ABSTRACT FROM AUTHOR]

In this study, the effects of two transparent UV curing coatings (i.e. epoxy acrylate and urethane acrylate) modified by zero, 0.2, and 0.5 loading percent of zinc oxide nanoparticles (ZN) on the weathering resistance of thermally modified timber were investigated. Both coatings improved the weathering resistance of the modified wood; however, epoxy acrylate showed much better performance compared to urethane acrylate. ATR-FTIR results showed no considerable oxidation or chain scission in the epoxy acrylate-coated specimens after six months of weathering, while significant chemical changes occurred in the urethane acrylate-coated specimens. The addition of the nanoparticles reduced the discoloration of both coatings; however, the contact angle and roughness were not significantly affected. Results also showed that the adhesion strength was reduced for both coatings as a result of weathering with the urethane acrylate coating having a lower adhesion strength than the epoxy acrylate. The addition of the ZN, particularly at the higher content, reduced the adhesion strength of the urethane acrylate coating. Generally, the method of fast and simple UV-cured coating of epoxy acrylate alone or coupled with zinc oxide nanoparticles was found to be effective for the protection of thermally modified timber against weathering in outdoor applications. [ABSTRACT FROM AUTHOR]

Freshly cut 30-mm-thick wood disks of Scots pine, Caucasian elm, narrow-leafed ash, wild cherry, black walnut, and European alder with various natural grade defects were dried together in a radiofrequency-vacuum (RF/V) dryer. A mild four-step drying schedule at the maximum temperature of 45 °C and power density in the range of 1-2 kWm−3 with an "on-off" control of RF radiation at the final step was used. The moisture content of the disks at the end of drying ranged from 10.6% to 13.4%. An almost uniform radial moisture gradient developed in the dried disks. The six wood species, however, exhibited variations in checking. The RF/V drying schedule used here was able to completely inhibit near-bark radial checking in all disks but pine and elm, whereas it failed to efficiently prevent V-cracking in pine and ash with a high mean tangential to radial shrinkage anisotropy (ST/SR). A strong positive correlation was also found between ST/SR and the proportion of V-cracked disks. The occurrence of ring failure within the reaction wood-containing disks of walnut, pine, and elm was almost completely prevented by the drying schedule, but a significant correlation was observed between the pith eccentricity and V-crack length in the compression wood-containing disks of pine. All other natural defects, i.e., scar in cherry, bark pocket, double or triple pithing in walnut and elm, sound knots in pine, and roundness deviation, exhibited no statistically significant effect (p > 0.05) on check formation. [ABSTRACT FROM AUTHOR]

The use of pyrolysis acid (PA) as a liquid by‐product of the slow pyrolysis of wood or any other lignocellulosic biomass has been widely developed in agriculture for a variety of purposes such as crop enhancement or as a pesticide. Evidence from the literature suggests that PA could be used as a sustainable wood preservative to protect against rot fungi and termites. The experimental work presented here provides one of the first investigations into the anti‐decay efficiency of PA. Crude PA acid acquired from three different types of wood at two different temperature ranges (180–280 °C and 280–350 °C) was used to impregnate beech and pine wood samples in a full‐cell process. Then, the resistance of treated samples against white and brown rot fungi was evaluated (in accordance with European standard EN 113), before and after a leaching test (European standard EN 84). It was found that, generally, higher retention of chemicals inside the wood was observed with PA obtained at 350 °C (PA‐350). The leaching rate of chemicals from the treated samples with PA obtained at 280 °C (PA‐280) was significantly higher than from those treated with PA‐350. Before leaching, no statistical difference was observed among the impregnated woods in terms of decay resistance. Although the samples treated with PA‐280 initially showed fairly good decay resistance they partially lost it after leaching. This was particularly the case with brown rot. However, the impregnation of wood samples with PA‐350 met the requirements of EN 113 as an efficient treatment against basidiomycete fungi. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]