Bamboo is an ideal material as it is green, fast-growing, and easy to process. However, the low dimensional stability may limit the application of bamboo due to its richness in hydrophilic groups. Thus, an effective and environment-friendly modification is needed to solve the aforementioned problems. This study employed high-temperature hydrothermal treatment for the modification of bamboo to offer technical support to further promote the application of bamboo materials. Bamboo was heated at various temperatures (120–160 °C) for diverse durations (60–120 min), and the chemical composition, mechanical properties, dimensional stability, and surface color were studied. Results revealed that the parenchyma cells of bamboo were deformed and the parenchymal cell lumen without starch granules after treatment at 160 °C for 120 min. The cellulose and hemicellulose content of bamboo decreased, and the lignin content increased in relative terms as the temperature and time of high-temperature hydrothermal treatment continued to rise. The mechanical properties of bamboo declined after high temperature hydrothermal treatment, and the modulus of rupture (MOR) and modulus of elasticity (MOE) of bamboo at 160 °C for 120 min decreased by 47.11% and 16.14%, respectively, compared to untreated bamboo. The swelling test indicated that the dimensional stability of the bamboo was improved, and the swelling ratio of the bamboo was reduced through the high-temperature hydrothermal treatment. The tangential and radial swelling coefficients of bamboo were reduced by 53.28% and 53.59%, respectively, after treatment at 160 °C for 120 min compared to untreated bamboo. The bamboo surface color was darkened after heat treatment, which gives the bamboo better surface decorative properties.

By promoting greenhouse gas sequestration, bamboo and bamboo-based products can improve carbon storage, and thus help decrease greenhouses gas emission through replacing traditional products like concrete, steel, and alloy. Thermal modification is a useful way to effectively enhance the dimensional stability and mold-resistance property of bamboo and bamboo-based products compared with chemical treatment. This work investigates the change in anti-mildew properties, micro-structure, and chemical composition of bamboo after heat treatment. Saturated steam heat treatment was applied for this project. SEM results showed that the structural damage of parenchyma cells resulted in the separation of thin-walled cells and vascular bundles. Thus, the original regular structure of bamboo, characterized by plump and intact cells, changed markedly. After thermal modification, bamboo samples exhibited improved dimensional stability and anti-fungal properties due to the decrement of hemicellulose and cellulose. The hardness and MOE of the modified bamboo were 0.75 and 20.6 GPa, respectively.

Bamboo is one of the most promising biomass materials in the world. However, the poor anti-mildew property and poor dimensional stability limits its outdoor applications. Current scholars focus on the modification of bamboo through heat treatment. Arc-shaped bamboo sheets are new bamboo products for special decoration in daily life. In this paper, we reported pressure-steam heat treatment and explored the effect of pressure-steam on the micro-structure, crystallinity index, anti-mildew, chemical composition, physical properties, and mechanical properties of bamboo via X-ray diffractometer (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), wet chemistry method and nanoindentation (NI). Herein, saturated-steam heat treatment was applied for modified moso bamboo for enhancing the anti-mildew properties and mechanical properties of moso bamboo. Results showed that with the introduction of saturated steam, the content of hemicellulose and cellulose decreased, while the lignin-relative content increased significantly. The anti-mildew property of moso bamboo was enhanced due to the decomposition of polysaccharide. Last, the modulus of elasticity and hardness of treated moso bamboo cell walls were enhanced after saturated-steam heat treatment. For example, the MOE of the treated moso bamboo cell wall increased from 12.7 GPa to 15.7 GPa. This heat treatment strategy can enhance the anti-mildew property of moso bamboo and can gain more attention from entrepreneurs and scholars.

In this paper, quasi-static nanoindentation was applied for investigating the influence of superheated steam on microstructure and micromechanical properties of Moso bamboo cell walls. The changes of mico-morphology, chemical composition, cellulose crystallinity index, micro-mechanical properties of bamboo were analyzed via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and nanoindentation. As expected, the content of hemicellulose and cellulose showed a downward trend, whereas the relative lignin content increased. Elastic modulus and hardness of the cell wall increased compared with that of the untreated sample. The elastic modulus and hardness of bamboo increased from 11.5 GPa to 19.5 GPa and from 0.35 GPa to 0.59 GPa. Furthermore, results showed that the creep resistance positively correlated to treatment severity.

The shortage of wood resources and the policy of logging restrictions have hindered the development of the wood industry. The development of fast-growing wood can effectively solve the problem of wood shortages and the discrepancy between supply and demand; however, the softness and poor strength of fast-growing wood make it difficult to use directly and restrict its applications. Meanwhile, the inflammability of wood is also a crucial hindrance to its application. In this work, hybrid wood composites with high strength and excellent fire retardance were developed by using a combined strategy of “delignification–mineralization–densification”. Delignification promoted the deposition of minerals inside the wood, and the mineralization process was able to significantly increase the fire retardance performance of the hybrid wood. The densification treatment made the wood and minerals closely packed, which was conducive to the improvement of the strength and fire retardance performance of the hybrid wood. The resulting hybrid wood composites showed enhanced mechanical strength (the tensile strength, flexural strength, and compressive strength were 180.6 MPa, 159.8 MPa, and 86.5 MPa, respectively) and outstanding fire retardance, and this strategy provided a feasible pathway towards the high-value application of fast-growing wood.