Wooden structures in China’s ancient buildings hold highly historical and cultural values. There is an urgent need to repair and replace the damaged wooden structures after hundreds and thousands of years of exposure to weather. Unfortunately, to date there is still a lack of insightful understanding on how the chemical structure, composition, and micro-morphology evolve over the long-term natural aging before artificial ancient timbers can be developed. This work aims to systematically examine the outer surface, middle layer, and inner surface of the same piece of Chinese fir (Cunninghamia lanceolate) collected from an ancient Chinese building. Based on qualitative and quantitative analysis, both cellulose and hemicellulose in aged woods are found to experience significant degrees of degradation. The crystalline regions of cellulose are also determined to undergo moderate degradation as compared to the control fresh wood. In comparison, the lignin basically remains unchanged and its content in the inner layer slightly increases, as evidenced by more free phenol groups determined. Relative to the outer and inner layer, the middle layer of the ancient wood shows the lowest degree of degradation close to that of the fresh wood. This work offers guidelines for fabricating artificial ancient woods to repair the destroyed ones in China’s ancient architectures.

This study investigated the effects of thermal modification treatment on flattened bamboo lumber by using temperature (180 °C, 190 °C, 200 °C) and duration (2, 3, 4 h) as experimental variables. The physicochemical properties, crystallinity, bending deformation, chemical composition, and microstructural evolution of the material before and after treatment were systematically analyzed using universal mechanical testing, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and nanoindentation. This comprehensive approach aimed to achieve high-performance flattened bamboo lumber. The results revealed that thermal modification significantly reduced the flexural modulus of elasticity and hardness of the flattened bamboo lumber, which reached their minimum values of 4479 MPa and 786.71 N, under the treatment at 190 °C/3 h. Conversely, it enhanced the longitudinal compressive strength of flattened bamboo lumber, achieving a maximum value of 57.28 MPa at 180 °C/2 h. At the microscale, the nanomechanical strength decreased under 190–200 °C treatments, accompanied by a tighter cell arrangement and evident shrinkage and deformation of the parenchyma cells. Dimensional stability tests combined with FTIR and crystallinity analyses demonstrated a reduction in the number of hydrophilic groups and improved dimensional stability after thermal modification. Notably, the material treated at 200 °C for 4 h retained its dimensional stability and exhibited no deformation.

In this study, novel and stable cellulose-based oleogels with tunable rheological properties were successfully developed for lubrication applications via cross-linking reactions of epoxidized soybean oil (ESO), microcrystalline cellulose (MCC), and isocyanate. This cross-linking strategy not only overcomes the incompatibility issue arising from the polarity difference between MCC and ESO but also enables precise control over the oleogels’ rheological behavior by tailoring the cross-linking density. The resulting oleogels exhibit excellent thermal stability, with an initial decomposition temperature (T_5%) of approximately 300 °C. Furthermore, oxidation resistance is significantly enhanced with increasing cross-linking density, resulting in a substantial increase in the oxidation induction time (OIT) from 5 to 79 min at 210 °C. Rheological characterization reveals that the oleogels exhibit typical shear-thinning and thixotropic behavior. The plateau modulus ($G_N^0$) exhibits a positive correlation with cross-linking density, accompanied by a simultaneous improvement in structural recovery ability. Tribological tests show that the friction coefficient increases with the cross-linking degree, while four-ball tests indicate that the extreme-pressure load-carrying capacity is governed mainly by the nature of the base oil in addition to the cross-linking density of the gel network. This work provides a promising strategy for the development of high-performance and customizable bio-based lubricating materials.