Microstructure and physicochemical properties of the anisotropic moso bamboo (Phyllostachys pubescens) surface

The surface of moso bamboo (Phyllostachys pubescens) was commonly removed in the mechanical processing for bamboo-based composites because of its poor wettability, permeability and glueability, which resulted in resources wastes. Research on the utilization of bamboo surface resources and the surface properties modification requires a thorough understanding of the properties of the anisotropic bamboo surface. In this study, the moso bamboo culm was divided into three layers in the radial direction of the culm wall, and the microstructure and physicochemical properties of each layer were investigated. The results revealed that from the green surface to the culm middle portion, moso bamboo presented a smooth, condense, and non-cell structure, followed by stomata, rectangular cells, and oval cells, then normal bamboo structure of parenchyma and fibril cells in the middle portion. The elemental and chemical analysis revealed the moso bamboo surface was composed of wax, under which silicon was deposited. The thermal stability analysis further confirmed that silicon distributed under the wax, otherwise the initial surface, and the initial layer showed no typical thermal decomposition behavior of the other two layers. Notable differences in the absorption band position and the intensity were observed among the FTIR spectra of the different samples, revealing that FTIR could be used as a potential approach to identify the chemical structure difference among the surface samples. The results of this research may provide fundamental information on the bamboo surface for surface properties modifications and/or resources utilizations.