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The aim of the study was to develop a simple and cost-effective method to improve thermal insulation and hydrophobicity of wood. Herein, we attempted to use commercially available silica aerogel powders suspended in ethanol to treat the wood by a simple vacuum impregnation process. The effects of particle size (20 µm and 40 nm) of silica aerogels and the number of impregnation cycles (1, 3, and 5 cycles) were examined on the thermal conductivity and the surface hydrophobicity. The results showed that the thermal conductivity of silica aerogel-impregnated wood decreased by approximately 38%. The water contact angle of the impregnated wood increased up to the maximum values 153° with a comparison with 80° of the untreated wood, indicating effective hydrophobization after silica aerogel impregnation. The tensile properties of the impregnated wood were found slightly improved. The results indicate that the impregnation of silica aerogel powders in wood can be a facile and efficient approach to prepare wood with thermal insulation and hydrophobicity, which may hold great promise to be employed in manufacturing wood-based materials used in interior decoration and buildings.

In this study, amino-functionalized magnetic γ-Fe2O3/sawdust composites (MSC-NH2) were investigated as biological absorption materials for removing Cu2+ ions from aqueous solution. These composites were fabricated by precipitated γ-Fe2O3 nanoparticles on sawdust substrate and then functionalized with 1,6-hexanediamine. Characterization of MSC-NH2 was performed by means of SEM, TEM, XRD, FTIR, BET, MPMS and XPS analysis to discuss the uptake mechanism. As a result, the amino groups are grafted upon the sawdust surfaces. The MSC-NH2 could be effectively used to remove Cu2+ from aqueous solution and be separated conveniently from the solution with the help of an external magnet. Batch experiments show that the adsorption equilibrium is achieved in 150 min, and the adsorption capacity is 7.55 mg/g at pH 6 and room temperature. The isotherm analysis indicates that the sorption data could be represented by Langmuir isotherm models. The kinetics is evaluated utilizing the Lagergren pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion models. Thermodynamic parameters reveal the spontaneous, endothermic and chemical nature of adsorption.

Bamboo fiber bundles (BFB) were firstly isolated by using the method of high-temperature saturated steam pretreatment following with mechanically rub-twisting. The microstructure, chemical composition, cell-wall mechanics, water absorption and tensile properties of BFB were then characterized and the interrelationships among the investigated properties were analyzed. Results indicated that thermal - mechanical isolation method can effectively extract the fiber bundles from bamboo culms with little damage on the microstructure of bamboo fibers. Both the hygroscopicity and cell-wall mechanics of BFB have been improved due to the degradation of hemicelluloses and increased crystallization degree induced by the saturated steam at the temperature of 180 °C for 30–40 min. BFB presented an obvious advantage in tensile properties as compared to other fibrous materials and were invulnerable to the thermal–mechanical isolation, which opens up the potential applications to reinforce the polymer matrix composites instead of synthetic fibers. Furthermore, the bending strength and modulus of laminated veneer lumber increased significantly with the addition of BFB, indicating that the isolated BFB also has the potential to be applied on engineered composites.

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