With the scarcity of wood resources and calls for “substituting bamboo for wood” and “substituting bamboo for plastic”, bamboo has gained greater popularity for its abundant reserves and outstanding mechanical properties. However, Mildew is a common problem for bamboo, which can significantly reduce the quality and service lives of bamboo products. In this work, a safe, eco-friendly, controllable and efficient method of gamma-ray irradiation was used to modify bamboo. The irradiation dose, moisture content (MC), and irradiation dose rate were adopted as factors of an orthogonal experiment. The results showed that the bamboo strips reached their best mechanical properties under the condition of irradiation at 150 KGy doses, moisture content of 40%, and irradiation dose rate of 44 KGy/H. In addition, the change in the chemical composition of bamboo and mildew resistance was also explored in this paper. The major chemical components (cellulose, hemicellulose and lignin), as well as starch, were degraded, and the bamboo strips exhibited excellent mildew resistance after gamma-ray irradiation.

Bamboo flattening technology provides an efficient approach for improving bamboo utilization, but the heterogeneous stress response and the mechanism of bamboo nodes during the flattening process remain insufficiently understood. In this study, a universal mechanical testing machine equipped with a temperature-controlled chamber was used to simulate the stress state during the flattening process. The effects of different heat treatment temperatures on the transverse mechanical response and chemical properties of different layers of bamboo internodes and nodes were systematically investigated. The results showed that at room temperature, the transverse strength of bamboo exhibited a gradient characteristic of outer layer bamboo (OB) > middle layer bamboo (MB) > inner layer bamboo (IB). Nodes showed higher transverse strength than internodes. As the temperature increased, the transverse properties of all layers significantly declined, with transverse tensile strength showing higher sensitivity. The IB exhibited the poorest thermal stability. Chemical analysis revealed the continuous degradation of cellulose and hemicellulose, while the relative lignin content and relative crystallinity of cellulose increased. This study clarifies the mechanism of heat treatment temperature on the physicochemical characteristics of different parts of bamboo, providing a scientific theoretical basis for temperature control in the industrial production of crack-free flattened bamboo boards.