High-strength bamboo fiber (HSBF) and bamboo fiber reinforced epoxy composites (BFRECs): Preparation, tensile performance and water-proof effect of resin precoating (RPC) treatment

Bamboo fiber (BF) is a promising natural fiber due to its abundant raw material, low cost, sustainability, and environmental friendliness. This study extracted high-strength BF (HSBF) from raw bamboo culm and introduced a simple resin precoating (RPC) method to waterproof HSBF surfaces. The effectiveness of RPC treatment was evaluated through water-absorption and cyclic wetting-drying tests. Furthermore, bamboo fiber reinforced epoxy composites (BFRECs) were fabricated using HSBF and epoxy adhesive. Their tensile performance was tested, and the impact of HSBF RPC treatment on the composites was assessed via boiling followed by tensile testing.Results indicate the extracted HSBFs exhibit diameters ranging from 0.06 mm to 0.32 mm, primarily distributed between 0.12 mm and 0.18 mm. Their average tensile strength is 1.27 ± 0.063 GPa with a Young’s modulus of 72.6 ± 4.9 GPa. When comprehensively evaluating strength, specific strength, sustainability, energy consumption, and cost, HSBF demonstrates superior overall performance compared to common synthetic fibers like carbon, glass, and steel fiber. RPC treatment provides waterproofing, reducing water absorption by approximately 40 %. It mitigates, but cannot prevent, the adverse effects of wetting-drying cycles on HSBFs.Owing to the outstanding tensile properties of HSBFs, the fabricated BFRECs achieved an average tensile strength of 628 MPa and Young’s modulus of 62.4 GPa, surpassing many other biocomposites and reaching the level of low-grade synthetic fiber reinforced polymers. RPC treatment significantly enhanced the water resistance of the biocomposites. Crucially, BFRECs incorporating RPC-treated HSBFs exhibited markedly superior tensile performance post-boiling compared to composites using untreated HSBFs. This study successfully combined an innovative HSBF extraction method with RPC treatment to enhance fiber water resistance and tensile properties, thereby boosting the application potential of both HSBF and BFRECs. • High-strength bamboo fibers (HSBFs) exhibit 1.27 ± 0.063 GPa strength and 72.6 ± 4.9 GPa modulus. • First application of RPC on bamboo fiber reduces water absorption by 40 % and mitigates wetting-drying damage. • RPC improves hydrothermal stability, reducing strength/modulus loss by 9%/13% in composites after boiling. • BFRECs achieve 628 MPa strength and 62.4 GPa modulus, exceeding conventional biocomposites.