Constructing aramid nanofibers self-assembly structure on fiber surface with electric field-assisted enhances insulation performance of aramid fiber reinforced epoxy resin

Aramid fiber reinforced epoxy resin composites (AFEP) exhibit excellent mechanical strength and insulation properties, making them key materials for insulation pull rods in Gas-Insulated Switchgear (GIS). The unique long-chain benzene ring structure in aramid fiber molecules ensures high performance but also reduces surface roughness and chemical reactivity, hindering the formation of stable interfacial structures with polymers like epoxy. This study proposes using an electric field-assisted method to construct the aramid nanofiber (ANFs) self-assembly structure on the aramid fiber surface, increasing roughness and chemical reactivity, thereby enhancing the interfacial bonding strength and insulation properties of AFEP. Testing revealed that the ANFs self-assembly structure was successfully formed on the aramid fiber surface, leading to improvements in both the electrical and mechanical properties of AFEP. The performance of AFEP material was optimal when the electric field-assisted treatment was carried out for 3 min. The flashover voltage was increased by 36.75 %, and the breakdown field strength was increased by 69.08 %. The tensile strength and shear strength were increased by 17.79 % and 30.92 %, respectively. Through molecular simulation, the results show that the addition of ANFs can enhance the interface bonding strength of the model by about 35.5 %. The diffusion coefficient of the epoxy resin was reduced by 68.1 %, indicating that the interface properties of the modified composite were greatly improved. This modification method provides a new idea for non-destructive enhancement of the comprehensive properties of aramid fiber epoxy resin materials.