Multi-scale evaluation of the effect of saturated steam on the micromechanical properties of Moso bamboo

Abstract

The changes in chemical composition and micro-mechanical properties of Moso Bamboo fiber cells were evaluated by applying saturated steam heat treatment at 160, 170, and 180 °C for periods of 4, 6, and 8 min, and subsequent analysis by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopic, and nanoindentation methods. The hemicellulose and cellulose content decreased as expected, while the relative lignin content showed an upward trend. Significant changes in the bamboo micro-structure were detected by scanning electron microscope under the action of high-temperature and saturated steam. Both temperature and time were shown to affect micromechanical properties of the bamboo cell wall. In addition, higher cell wall elastic modulus and hardness were observed (a rise from 16.1 to 19.2 GPa and from 0.6 to 0.8 GPa, respectively), as compared with those of the untreated sample. Meanwhile, the creep ratio decreased after saturated steam heat treatment.