Synergistic Surface Modification Of Bamboo Fibers For High-Performance Green Epoxy Composites

Abstract Natural fiber-reinforced polymer composites hold great promise as lightweight structural materials, yet their mechanical performance is often constrained by structural damage during fiber extraction and poor interfacial adhesion with polymer matrices. Here, we report a synergistic surface modification strategy that combines mild alkali delignification with aminopropyltriethoxysilane (APTES) grafting to tailor the surface chemistry and topography of continuous bamboo strips. This approach preserves the native alignment of cellulose microfibrils, increases accessible hydroxyl groups, and establishes a robust covalent bridge between bamboo and epoxy resin. The optimally modified bamboo strip achieves a tensile strength of 823.1 MPa, representing a 78.1% increase over untreated bamboo. The resulting unidirectional epoxy composite exhibits a tensile strength of 502.3 MPa and a specific tensile strength of 401.84 MPa/(g·cm−3), surpassing many metallic structural materials. Interfacial shear strength increases by 204.5% to 25.7 MPa, attributed to a dual “chemical bonding and mechanical interlocking” mechanism. The composite also demonstrates stable hydrophobicity, enhanced thermal conductivity, and good antifouling performance. This work presents a scalable, low-carbon route to high-performance bamboo-based composites, offering a sustainable alternative for lightweight applications such as battery enclosures and protective housings.