Eco-friendly and special-shaped bamboo binderless fiberboards fabricated by self-bonding technology: Effect of bamboo fibers with different sizes

The development of bamboo binderless fiberboards (BBFBs) has gained growing momentum due to being free of formaldehyde adhesive that often causes environmental and health problems. However, the immature fabrication process and poor shape adaptability of fiberboards hinder the practical applications of the BBFB products. Here, we proposed to manufacture special-shaped BBFBs using water as a “flow agent” and then hot-pressing. This fabrication process required the prompt drainage of water from the fiberboards, which might be largely affected by the size of bamboo fibers. The effect of the size of bamboo fibers was examined on morphology, void characteristics, water resistance, and mechanical properties of BBFBs. The results showed that larger bamboo fibers (< 120 mesh) in the BBFBs would be beneficial to drain water during hot pressing. On the contrary, an excessive volume fraction of smaller bamboo fibers (> 120 mesh) resulted in bulging. The optimal size of bamboo fibers was crucial to obtain BBFBs with desirable performances. It was easier for smaller bamboo fibers to form physical and chemical bonding under mechanical effects, hydrothermal effects, and self-bonding. The flexural strength and flexural modulus of BBFBs could be as high as 11.2 MPa and 2.16 GPa, respectively. It was recommended that bamboo fibers of greater than 120 mesh in BBFBs be controlled at around 60%. Eco-friendly and special-shaped BBFB products can be fabricated conveniently through mold design, which holds great potential for furniture and packaging applications.