Surface characterization and biodegradability of sodium hydroxide-treated Moso bamboo substrates

Alkali solution immersion is widely used in pretreatment during bamboo and wood product manufacturing. In this study, we performed a surface analysis on the bamboo chips pretreated by sodium hydroxide with different concentrations at room temperature (25 ℃) and evaluated the surface performance and biodurability. Bamboo surface rapidly changed to darker color at sodium hydroxide concentration (NaOH) of 5% and become rough at 20% NaOH. The K-M curve showed absorption peak near 390-410 nm after alkali treatment, which was due to the presence of chromophore groups derived from lignin, especially from methylene quinone. X-ray diffraction (XRD) showed the area of the crystallization zone was enlarged rapidly at 5% NaOH and then declined. Fourier transform infrared spectroscopy illustrated the conjugate structure of lignin-phenols changed after proton transfer in hydroxyl radical solution and this was the main reason for the surface color changes. During alkali treatment, lignin and hemicellu...