Change in Micro-Morphology and Micro-Mechanical Properties of Thermally Modified Moso Bamboo

Abstract

In recent years, saturated steam heat treatment has been considered as an environmentally friendly and cost-effective modification method compared with traditional heat treatment media. In this study, bamboo was treated by saturated steam, and the change in chemical composition, cellulose crystallinity index, micro-morphology, and micromechanical properties were analyzed by a wet chemistry method, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), nanoindentation, and so on. Results illustrated that the parenchyma cell walls were distorted due to the decomposition of hemicellulose and cellulose in bamboo samples. As expected, the hemicellulose and cellulose content decreased, whereas the lignin content increased significantly. In addition, the cellulose crystallinity index and thus the micromechanical properties of bamboo cell walls increased. For example, the hardness increased from 0.69 GPa to 0.84 GPa owing to the enhanced crystallinity index and lignin content.