Development of high-performance basalt fiber-reinforced polymer composite using a nanocellulose-based surface modification strategy

• Development of high-performance BFRP composites using two eco-friendly materials: basalt fibers (BF) and nanocellulose (NC). • Enhancement of interfacial bonding in BFRP composites through an aqueous NC dispersion and grafting strategy. • Demonstration of the limitations associated with the conventional NC–epoxy mixing method. • Fabrication of moisture-resistant BFRP composites with improved long-term durability. Basalt fibers (BFs) have emerged as a promising alternative reinforcement material for developing fiber-reinforced polymer (FRP) composites, due to their lower environmental impact compared with traditional fibers such as carbon and glass. However, the weak interfacial bonding between BFs and the polymer matrix limits the mechanical performance of basalt fiber-reinforced polymers (BFRPs). In this work, nanocelluloses (NCs), including cellulose nanofiber (CNF) and cellulose nanocrystal (CNC), were investigated as bio-based interfacial modifiers to enhance fiber–matrix adhesion and improve the mechanical performance of BFRP. While direct incorporation of NC into epoxy resin is challenging due to its poor dispersibility in hydrophobic media, NCs readily redistributes in water because of their hydrophilic nature. Taking advantages of this property, a grafting technique was developed in which NCs were first dispersed in water and then chemically grafted onto silanol-functionalized BF surface. This novel approach enabled more effective interfacial interaction between the fiber and the matrix. The grafting process was confirmed through X-ray photoelectron spectroscopy (XPS), while scanning electron microscopy (SEM) of the fractured surfaces after the interlaminar shear strength (ILSS) test. Mechanical testing demonstrated that NC-grafted BFRP composites exhibited significantly enhanced interfacial bonding and mechanical performance compared with conventionally mixed NC–epoxy and unmodified BFRP composites. CNF grafting led to improvements of 24% in tensile strength, 74% in impact resistance, and 61% in ILSS, while CNC grafting resulted in 16%, 79%, and 107% improvements, respectively. This work presents an environmentally friendly approach to enhance BF–matrix bonding strength and improve overall composite performance.