Quasi-static and dynamic nanoindentation to determine the influence of thermal treatment on the mechanical properties of bamboo cell walls

Bamboo was thermally treated at 180 degrees C and 200 degrees C, and the micromechanical properties of its cell walls were investigated by means of quasi-static and dynamic nanoindentation experiments. With increasing treatment temperatures, the average dry density and mass of the bamboo decreased, whereas the already reduced elastic modulus at 180 degrees C of the fiber cell walls did not change, but the hardness showed increasing tendencies. Dynamic nanoindentation revealed reduced storage modulus (E-r') and loss modulus (Er '') for the thermotreated bamboo cell walls compared with the untreated bamboo fibers in all frequency regions. Moreover, E-r', E-r '', and loss tangent (tan delta) of treated bamboo decreased with increasing treatment temperature.