Multifunctional Self‐Bonding Biocomposites Enabled by Uniform Dispersion of Carbon Nanotube via In Situ Lignin and Multiple Noncovalent Bonds

ABSTRACT In the 5G era, electromagnetic pollution poses an invisible threat to human safety. Given that electromagnetic wave (EMW) absorption invariably generates heat, this phenomenon may induce structural degradation of the material and pose safety risks. It is crucial to develop high‐strength, flame‐retardant electromagnetic interference (EMI) shielding materials. Herein, we propose a green and sustainable approach to induce stable dispersion of carbon nanotubes (CNTs) with in situ lignin and non‐covalent bonding in waste bamboo materials. The in situ lignin released during bamboo fiber pretreatment was utilized as a “bridge” to enhance the interfacial bonding between CNTs and the fibers, and co‐assembles with the CNTs through inter‐boundary hydrogen bonding, electrostatic stabilization, and π–π stacking. Then, biocomposites were synthesized in one step by hot pressing, using molten in situ lignin as a green binder for self‐bonding. The biocomposite exhibits excellent EMI shielding performance (72.5 dB), superior mechanical properties, flame retardancy (total heat release reduced by 35.22%, Total smoke production reduced by 81.58%). It offers a sustainable approach to developing multifunctional structural materials for the construction, aerospace, and military sectors.