Enhanced aramid fiber epoxy resin composites insulation properties via π-π stacking driven ZnONW heterojunction growth to reconstruct aramid fiber surface

Abstract

The Gas-insulated switchgear (GIS) is the core component in the development of China's new ultra-high voltage power system. Its key part, the insulation pull rod, needs to withstand substantial mechanical loads and impact voltages. The poor compatibility between aramid fiber and epoxy resin is the key problem that affects the insulation performance of pull rods. This paper proposes a method to reconstruct the surface of aramid fibers by utilizing the π-π stacking of iron phthalocyanine (FePc) and the heterojunction growth of zinc oxide nanowires (ZnONW). This approach roughens the fiber surface and improves compatibility, effectively enhancing the insulation performance of aramid fiber-epoxy resin composites. The characterization techniques such as ultraviolet photoelectron spectroscopy (UPS) confirm the π-π stacking effect of FePc and its formation of a heterojunction with ZnO. The insulation performance tests indicate that with a growth concentration of 100 mM and a growth time of 2 h, the aramid fiber-epoxy resin composite exhibits optimal insulation properties. Under these conditions, the breakdown voltage increased by 73.02 %, and the breakdown electric field strength improved by 72.13 %. Molecular dynamics (MD) simulations and density functional theory (DFT) analyses reveal the π-π stacking process and the mechanisms behind the enhanced insulation properties.