Qiheng Tang

Conventional lighting devices exhibit low brightness and safety hazards (including short circuits and electrical sparks), limiting their use in specialized environments like historic buildings, ammunition depots, and underground mines. To overcome these challenges, laser‐driven wood fiber diffusers (LWFD) were developed using renewable, low‐cost wood waste. This eco‐friendly approach involves a simple, low‐energy process with delignified wood fibers, polyethylene glycol diacrylate (PEGDA), and yttrium aluminum garnet phosphor, followed by photocuring. The refractive index mismatch between the fibers (n ≈ 1.53) and PEGDA (n ≈ 1.42) induces Mie scattering, converting laser beams into uniform light. The isotropic structure ensures angle‐independent irradiation and uniform 3D illumination. With optimized phosphor content (0.2 wt.%) and fiber loading (2.5 g), LWFDs achieve a coefficient of illumination variation (CIV) of 4.10%, ensuring excellent uniformity. LWFDs remain stable from 100°C to −20°C and maintain a surface temperature of about 30°C during prolonged laser exposure. They emit stable white light (CIE coordinates: 0.33, 0.33), with photoluminescence intensity increasing linearly with laser power. LWFDs enable long‐distance wireless lighting, eliminating voltage drops, high wiring costs, and safety hazards, making them ideal for railways, historic buildings, and underground mines. The use of wood waste also supports sustainable resource recycling.

Plywood is lightweight, strong, and durable, making it a widely used material in building decoration and furniture areas. In this study, formaldehyde-free, high-strength plywood was prepared through the incorporation of carbon fiber fabrics (CFFs) as reinforcement layers and their bonding with maleic anhydride polyethylene (MAPE) films. Various tests were performed to assess the impact of the carbon fiber fabric positioning on the physical and mechanical properties of plywood, including tensile shear strength, flexural strength, water absorption, thickness swelling, and electro-thermal properties. The results revealed that the plywood with CFFs exhibited significantly higher mechanical properties than plywood without CFFs. Particularly, the addition of CFFs increased the tensile strength of the plywood by nearly 54.43%, regardless of the CFFs’ position. The symmetric placement of CFFs near the bottom and upper layers of the plywood resulted in a maximum modulus of rupture of 85.6 MPa. These findings were validated by numerical simulations. Scanning electron microscopy analysis of the plywood microstructures revealed that MAPE penetrated both the vessels and xylem of the wood veneers and the pores of the CFFs, thereby improving the mechanical properties of the plywood. Plywood reinforced with CFFs exhibited increased water absorption and thickness swelling after immersion. Additionally, the placement of CFFs influenced the electro-thermal properties of the plywood. Plywood with CFFs positioned near the bottom and upper surfaces exhibited superior thermal conductivity. Overall, this study presents a feasible method for developing high-performance, formaldehyde-free plywood and sustainable wood-based structural materials with potential applications in geothermal flooring.

To fabricate homogeneous bamboo fiber reinforced thermoplastic composites, polypropylene (PP) fiber and 3-aminpropyltriethoxysilane (APTES) modified bamboo fibers were first formed into mats by non-woven air paving technology, and then the composites were created by hot-pressing the mats. The modification of BFs was characterized by XPS and FTIR analyses, and the results confirmed that APTES had been grafted onto the surfaces of BFs. The effects of concentrations of APTES on the mechanical, physical, morphological, and thermal properties of the bamboo-polypropylene composites were examined by tests of bending strength, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and water absorption. The analysis of physical and mechanical properties revealed improved mechanical properties and water resistance (3 wt% of APTES). SEM images were used to assess the influence of modification treatment on the properties of the composites. The results confirmed that the modification of APTES improved the interfacial adhesion between BFs and PP matrix. DSC results indicated the melting point of composites decreased with an increase in concentration of APTES up to 3 wt%, while the melting point of composites increased when the concentration of APTES was higher than 3 wt%.

To improve the flame-retardant performance of bamboo fiber (BF) reinforced polypropylene (PP) composites, melamine pyrophosphate (MPP) and aluminum hypophosphite (AP) at a constant mass ratio of 2:1 were added. The influence of the MPP/AP mass fraction on the mechanical and flame-retardant properties of the BF reinforced PP composites were evaluated by mechanical testing, limiting oxygen index (LOI) and cone calorimetry. Mechanical tests demonstrate that tensile properties of BF/PP decreased with the increase of MPP/AP mass fraction, while flexural properties of composites exhibited very different tendencies. Both flexural strength and modulus increased slightly with the addition of MPP/AP at first, and then decreased significantly after a relatively high content of MPP/AP was loaded. This was due to the poor interfacial compatibility between PP and MPP/AP. The flame retardancy of BF/PP composites has been greatly improved. When 30% MPP/AP was loaded into the composites, the LOI increased to 27.2%, which was 42.4% higher than that of the composite without flame retardant addition. Cone calorimetry results indicated that MPP/AP worked in both gas and condensed phases during the combustion process. Peak heat release rate, total smoke production and mass loss of the composites were significantly reduced because of the addition of MPP/AP.

The demand for eco-friendly renewable natural fibers has grown in recent years. In this study, a series of polypropylene-based composites reinforced with single bamboo fibers (SBFs), prepared by non-woven paving and a hot-pressing process, were investigated. The influence of the content of SBF on impact strength, flexural strength, and water resistance was analyzed. The properties of the composites were greatly affected by the SBF content. Impact strength increased as SBF content increased. The modulus of rupture and modulus of elasticity show an optimum value, with SBF contents of 40% and 50%, respectively. The surface morphology of the fractured surfaces of the composites was characterized by scanning electron microscopy. The composites showed poor interfacial compatibility. The water resistance indicates that the composites with higher SBF contents have higher values of water absorption and thickness swelling, due to the hydrophilicity of the bamboo fibers. The thermal properties of the composites were characterized by thermal gravimetric analysis and by differential scanning calorimetry. The thermal stability of the composites was gradually reduced, due to the poor thermal stability of SBFs. In the composites, the maximum decomposition temperature corresponding to SBF shows an increasing trend. However, the maximum decomposition temperature of polypropylene was not influenced by SBF content. The melting point of the polypropylene in the composites was lower relative to pure polypropylene, although it was not affected by increasing SBF content.