The effects of fluorination on the vacuum surface flashover voltage of polyimide

Abstract

The effects of fluorination on the vacuum surface flashover voltage (U f ) of polyimide (PI) are researched. The experimental results show that as the degree of fluorination increases, the U f of PI firstly increases and then decreases, the highest U f in the experiments is increased by up to 21% compared with untreated PI sample. The results of Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectric spectroscopy (XPS) show that fluoride treatments may cause the structural change of PI. A mechanism based on the abstraction of the atoms of H, O and N is proposed. During the process of fluorination, the formation of the C-F bonds can improve the surface flashover voltage, whereas as the degree of fluorination increases, the destruction of the C-N bonds would degrade the surface flashover performance. The two processes play the role at the same time. Therefore, there is an optimal degree for the fluorination.

Surface modification of polymethyl-methacrylate using atmospheric pressure argon plasma jets to improve surface flashover performance in vacuum

“…It has been confirmed that some modifications (nano-coating or fluorination) on the polymer material surfaces can improve the surface insulation performance of insulators [23][24][25]. Fang et al treated a glass surface using DBD in the atmospherepressure air to improve the surface hydrophobicity and showed that the flashover voltage of the wet glass surface increased after the treatment [26].…”

Mechanism of F2/N2 fluorination mitigating vacuum flashover of polymers

“…Ke et al studied the influence of surface modification on vacuum flashover performance of insulators Journal of Physics D: Applied Physics Mechanism of F 2 /N 2 fluorination mitigating vacuum flashover of polymers and proved its effectiveness [16,17]. Cheng et al studied the effects of fluorination on the vacuum surface flashover voltage of polyimide [18]. It also has been proved by An and Du et al that appropriate fluorination is effective to suppress the accumulation of space charge [19][20][21][22][23][24][25].…”