A lightweight and high-strength epoxy composites based on graphene oxide modified kapok fibers

Lightweight and high-strength (LWHS) composites are widely used in aerospace, automotive and marine fields. However, it is difficult to maintain the strength of the material while decreasing its density, let alone increasing. In this work, inspired by the mechanism of fiber-reinforced polymers, a LWHS epoxy composite was constructed through hollow kapok fibers. Computational fluid dynamics simulations show that the hollow structure of kapok fiber can be effectively retained. The results show that the graphene oxide effectively improves the interfacial adhesion between kapok fiber and epoxy matrix. Decrease in specific gravity and the enhancement of mechanical properties can simultaneously realize in the LWHS composites via the interweaving of kapok fibers. At an optimal 1.5 wt% fiber content, the specific gravity of LWHS composites decreased by 20.3% while tensile strength , bending strength and compressive strength increased by 21.5%, 9.56% and 51.92%, respectively. Tensile modulus , bending modulus and compression modulus increased by 48.35%, 92.18% and 49.84%, respectively. • It proved the possibility that hollow fibers can be employed to construct lightweight and high-strength composites. • The reduction of specific gravity and the improvement of mechanical properties of the epoxy based composites can be achieved simultaneously by the kapok fiber. • Graphene oxide can be used as a potential surface treatment agent to effectively improve the surface properties of fibers.