Waterborne polyurethane coatings (WPU) are widely used in various types of coatings due to their environmental friendliness, rich gloss, and strong adhesion. However, their inferior mechanical properties and solvent resistance limit their application on the surface of wood products. In this study, graphene oxide (GO) with nanoscale size, large surface area, and abundant functional groups was incorporated into WPU by chemical grafting to improve the dispersion of GO in WPU, resulting in excellent mechanical properties and solvent resistance of WPU coatings. GO with abundant oxygen-containing functional groups and nanoscale size was prepared, and maintained good compatibility with WPU. When the GO concentration was 0.7 wt%, the tensile strength of GO-modified WPU coating film increased by 64.89%, and the abrasion resistance and pendulum hardness increased by 28.19% and 15.87%, respectively. In addition, GO also improved the solvent resistance of WPU coatings. The chemical grafting strategy employed in this study provides a feasible way to improve the dispersion of GO in WPU and provides a useful reference for the modification of waterborne wood coatings.

Fast-growing poplar wood has the bottleneck problems of inferior mechanical strength and poor dimensional stability. In this study, the wood was modified by combined treatments of pre-compression and post-vacuum-thermo modification to improve its mechanical strength and dimensional stability, simultaneously; in addition, the variation law of mechanical properties of the wood with compression ratio as well as the improvement effect of dimensional stability of the treated wood were mainly studied. The results show that the optimal temperature and time of the vacuum-thermo modification were 190 °C and 10 h, respectively. Under these conditions, the structure of pre-compressed and post-vacuum-thermally modified wood (CT wood) is gradually densified with the increase in the compression ratio, which results in the continuous enhancement of mechanical properties. Meanwhile, the anti-swelling efficiency (ASE) of the CT wood after water absorption is correspondingly better than that of the compressed wood before thermal modification, indicating that the dimensional stability of compressed wood was improved by the thermal modification. When the compression ratio was 70%, the modulus of rupture (MOR) and impact toughness of CT wood was 176 MPa and 63 KJ/m², which was 125% and 59% higher than that of untreated wood, respectively. The ASE was also 26% higher than that of the wood with sole compression. Therefore, this method improves the mechanical strength and dimensional stability of wood simultaneously, and it provides a scientific basis for optimization of the reinforcing modification process of fast-growing wood.

Wood is a viable alternative to traditional steel, cement, and concrete as a structural material for building applications, utilizing renewable resources and addressing the challenges of high energy consumption and environmental pollution in the construction industry. However, the vast supply of fast-growing poplar wood has bottlenecks in terms of low strength and dimensional stability, making it difficult to use as a structural material. An environmentally friendly acrylic resin system was designed and cured in this study to fill the poplar cell cavities, resulting in a new type of poplar laminated veneer lumber with improved mechanical strength and dimensional stability. The optimized acrylic resin system had a solid content of 25% and a curing agent content of 10% of the resin solid content. The cured filled poplar veneer gained 81.36% of its weight and had a density of 0.69 g/cm³. The static flexural strength and modulus of elasticity of the further prepared laminated veneer lumber were 123.12 MPa and 12,944.76 MPa, respectively, exceeding the highest flexural strength required for wood structural timber for construction (modulus of elasticity 12,500 MPa and static flexural strength 35 MPa). Its tensile strength, impact toughness, hardness, attrition value, water absorption, water absorption thickness expansion, and water absorption width expansion were 58.81%, 19.50%, 419.18%, 76.83%, 44.38%, 13.90%, and 37.60% higher than untreated laminated veneer lumber, demonstrating improved mechanical strength and dimensional stability, significantly. This method provides a novel approach to encouraging the use of low-value-added poplar wood in high-value-added structural building material applications.

Although cutting flow peanut-picking is the main peanut harvesting method, it has the problems of a large harvest loss and a high damage rate of peanut shells. The analysis of impact-friction contact characteristics during peanut fruit picking is crucial to illustrate peanut fruit picking damage. A typical peanut variety, “Dabaisha”, was considered in this study. The characteristics of peanut-picking impact-friction were studied using a peanut-picking impact-friction test bench under different conditions. An orthogonal test with three factors and levels was performed after the single-factor condition was determined. The apparent morphologies of peanut shells before and after the collision and friction tests were compared and analyzed using micro-computed tomography, white-light interferometry, and optical microscopy, whereas the impact-friction damage characteristics of peanuts under the influence of various factors were discussed. The results show that the orders of influence of the coefficient of friction of peanuts and wear loss of peanut pods were as follows: invasion depth > moisture content > contact linear velocity and moisture content > invasion depth > contact linear velocity, respectively. The experimental results and discussion in this study can provide a data reference for developing and designing peanut mechanization production equipment.

Third body plant fibers have an important influence on the friction and wear properties of metal friction pairs. In this study, wheat straw powder with different particle sizes was prepared, and a pin-on-disk friction tester was employed to evaluate the friction and wear properties of the wheat straw powder third body on steel friction pairs under various conditions. The results show that the straw powder played an isolation role in the steel–steel friction pair, which reduced the contact area between the pin and the disc and thus reduced the friction coefficient. Compared with the large particle size powder, the small particle size powder became embedded in the friction interface or in the groove caused by wear, buffered the friction stress, and reduced the friction coefficient and wear. When lubricants such as lubricating oil or lubricating grease were added, the friction coefficient was significantly reduced. Under the influence of lubricant, the particle size of straw powder had no significant effect on the wear. The results of this study can provide a reference for the third body friction and wear properties of straw powder and the design of friction pairs for metal parts.