High-Strength, Superhydrophobic, Flame-Retardant, and Smoke-Suppressing Functionalized Bamboo

Metal carbides and petroleum-based composites have excellent mechanical properties, but they are nonrenewable, expensive, and consume large amounts of energy during their production. To address these challenges, this study processed bamboo into a lightweight, high-strength, flame-retardant, smoke-suppressing, and superhydrophobic functional material using a four-step process. These enhanced properties were attributed to a multistep treatment process involving delignification, densification via hot-press drying, cold-press forming, and vacuum impregnation with liquid sodium silicate. The functional bamboo exhibited a 1.95-fold higher tensile strength, 5.60-fold higher impact toughness, and 2.61-fold higher hydrophobicity than natural bamboo, and its total heat release and total smoke content were only 1/4 and 1/8 of those of natural bamboo, respectively. The mechanical properties, hydrophobicity, and flame retardancy of functional bamboo were attributed to the tightly interwoven and dense structure formed by hot pressing and room-temperature cold pressing. Silicon dioxide formed a dual-scale rough film with microgrooves and nanoparticles on the surface of bamboo fibers. This increased the heat absorption due to the rapid decomposition of sodium silicate into silica and water vapor during combustion, which formed a barrier on the surface of bamboo. The functional bamboo reported here represents an environmentally friendly biomass material that can be applied in construction and transportation projects.