Plasma Fluorinated Nano-SiO₂ Enhances the Surface Insulation Performance of Glass Fiber Reinforced Polymer

With the extensive application of glass fiber reinforced polymer (GFRP) in the field of high voltage insulation, its operating environment is becoming more and more complex, and the surface insulation failure has gradually become a pivotal problem affecting the safety of equipment. In this paper, nano-SiO₂ was fluorinated by Dielectric barrier discharges (DBD) plasma and doped with GFRP to enhance the insulation performance. Through Fourier Transform Ioncyclotron Resonance (FTIR) and X-ray Photoelectron Spectroscopy (XPS) characterization of nano fillers before and after modification, it was found that plasma fluorination can graft a large number of fluorinated groups on the surface of SiO₂. The introduction of fluorinated SiO₂ (FSiO₂) can significantly enhance the interfacial bonding strength of the fiber, matrix and filler in GFRP. The DC surface flashover voltage of modified GFRP was further tested. The results show that both SiO₂ and FSiO₂ can improve the flashover voltage of GFRP. When the concentration of FSiO₂ is 3%, the flashover voltage increases most significantly to 14.71 kV, which is 38.77% higher than that of unmodified GFRP. The charge dissipation test results show that the addition of FSiO₂ can inhibit the surface charge migration. By the calculation of Density functional theory (DFT) and charge trap, it is found that grafting fluorine-containing groups on SiO₂ can increase its band gap and enhance its electron binding ability. Furthermore, a large number of deep trap levels are introduced into the nanointerface inside GFRP to enhance the inhibition of secondary electron collapse, thus increasing the flashover voltage.