In this work, the degradation behavior of bamboo scrimber are investigated under natural weathering system for six years. Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and colorimeter were used to characterize the change of bamboo scrimber surface and microstructure. Natural weathering led to degradation of lignin and rapid color changes, demonstrated by decrease of 1232 cm⁻¹, 1423 cm⁻¹ and 1506 cm⁻¹ absorption peaks, the reduction of C1and increase of C2, and ΔE* value notably. Lignin degradation resulted in micro-check formation in the cell walls of fibers and parenchyma cells within exposure time. In particular, parameters of weather resistance changed rapidly within the initial two years and stabilized in the following four years. It is also revealed that two natural regions with different type of climate have significantly affected the degradation behavior of bamboo scrimber.

The bamboo fiber-based composite (BFBC) has high-performce in terms of mechanical properties and dimensional stability. In this study, BFBCs were prepared with different hot-pressing temperatures (150 °C, 160 °C, 170 °C, 180 °C, 190 °C, and 200 °C) and designed with different densities (1.05 g/cm³, 1.10 g/cm³, 1.15 g/cm³ and 1.20 g/cm³), and their selected properties were evaluated. Temperature affected BFBC performance, which, with a general increase in temperature, showed a decrement in mechanical properties and an improvement in dimensional stability. Holocellulose content significantly decreased, and the color of BFBC became darker with the increasing of the press temperature. As the density of BFBC increased, the modulus of elasticity (MOE) significantly increased from 23.09 GPa to 27.01 GPa with the increase in temperature. The thickness swelling ratio (TSR), width swelling ratio (WSR) and water absorption ratio (WAR) declined by more than 30% with the increase in density. Overall, the results of this study provide a theoretical basis and a source of technical support to promote the design, application, and popularization of BFBC in different fields.

Reliability analysis of mechanical strength could be used for evaluation of wood scrimber properties in this study. Normal, lognormal, and Weibull distributions were used to determine and selected the optimal model for wood scrimber for the first time. The results of reliability analysis indicated that the bending and tensile strength were well fit for normal distribution. Weibull distribution could describe the probability distribution law of compression strength, and lognormal distribution could reflect the probability distribution law of shear strength, respectively. The standard value of each mechanical strength was determined and compared in accordance with two methods. This illustrated that a significant difference between these two methods is evident in the case of modulus of elasticity (MOE), compression strength (CS), and shear strength (SS), while modulus of rupture (MOR) and tensile strength (TS) yielded similar data. The improvement in mechanical strengths was remarkably affected by the increase in density. Moreover, the microstructure of wood scrimber has a good ratio of deformation with respect to density, which can be significantly explained by compressive densification. The results suggest that the deformation ratio increased from 49.75% to 78.67%, which might reflect the variation in macroscopic mechanical strength of wood scrimber.

Thermophysical molding (TPM) treatments can significantly improve the surface properties of thick wood veneer. To understand the effects of TPM treatments on the surface properties of thick veneer, the roughness, contact angles, and chemical changes were determined. The results indicated that the roughness of the thick veneer decreased when the temperature and the duration increased. The contact angles decreased when the temperature increased, resulting in better wettability. X-ray photoelectron spectroscopic (XPS) results provided information about the significant chemical changes in the surface with different TPM temperatures of 160–190 °C and durations of 5–11 min. Increases in temperature and duration increased the C content and decreased the O content during the treatment process. The most significant changes in the thick veneer that resulted from increasing the temperature and the duration were the increase in the C1 component and the decrease in the C2 component. Thus, the oxygen to carbon (O/C) ratio decreased and the ratio of aromatic carbon to aliphatic carbon (C1/C2) notably increased with the increasing TPM temperature. The TPM duration slightly affected the O/C ratio, but it had a stronger linear relation with the C1/C2 ratio. Additionally, the C1/C2 ratio and the O/C ratio had a linear statistical relationship with the initial wettability. These findings could provide useful information for the future utilization of thick veneers treated with TPM.

Surface damage during machining can limit the finishing quality of bamboo particleboard bonded with highly reactive isocyanate adhesives. Rather than replacing pMDI throughout the panel, this study evaluated soy protein adhesive as a surface-layer modifier. Three formulations were compared, including 2.2% pMDI with 4% soy protein adhesive solids (G1), 1.1% pMDI with 4% soy protein adhesive solids (G2), and only 2.2% pMDI (G3). FTIR showed spectral changes after curing in the amide and C-O/C-O-C regions. DSC revealed a thermal event at approximately 115–118 °C, which may reflect contributions from multiple overlapping processes. G1 had the highest MOR (18.54 ± 1.95 MPa), internal bond strength (0.80 ± 0.04 MPa), and surface bond strength (1.59 ± 0.23 MPa). The 24 h thickness swelling was 3.79 ± 0.25%, and the surface bond strength was approximately 56% higher than that of G3. In the G1-G3 cut-edge comparison, Ra was 13.8 μm for G1 and 30.3 μm for G3. Micro-CT gave mean pore volume fractions of 15.15%, 16.23%, and 23.76% for G1, G2, and G3, respectively. Overall, the utilization of soy protein adhesive in the surface layers improved surface bond strength and cut-edge roughness. These findings provide a promising opportunity toward high-quality bamboo particleboard manufacturing.