Investigation of the water vapor sorption behavior of bamboo fibers with different sizes

Recently, the demand for sustainable materials has given rise to new research interest in the intrinsic properties and applications of bamboo and its derivatives. Hygroscopicity plays an important role in the application of bamboo, and it is known that the size of the material particles affects the hygroscopicity of the material. To further understand the effect of the particle size, the bamboo fiber with a simple structure was destroyed by grinding, then equilibrated and dynamic sorption was studied by dynamic vapor sorption measurements. The obtained moisture sorption isotherm results showed that the maximum value of the moisture content of 19.69% was obtained in the medium-size fiber (MF) and the minimum value of 15.76% was obtained in the severely ground fiber (SF). As expressed by the slope of the fitting curves, MF showed the highest hygroscopic ability for the relative humidity > 30%. In addition, the sorption isotherm data were fitted by the Guggenheim-Anderson-de Boer (GAB) model, and the fitting results indicated small changes in the fiber monolayer water content between the samples with different fiber sizes. The largest difference of 0.53% was observed between control-size fiber (CF) and medium-size fiber (MF). Therefore, it was concluded that the differences between the moisture contents of the fibers with different sizes are mainly due to the differences in multilayer water sorption.