Novel low dielectric loss polyimide film: synthesis and high frequency electrical properties

The thioether structure was introduced into the poly (N, N’- phenoxyphenyl pyromellitimide) (PMDA-ODA), owing to the extremely low dielectric loss of polyphenylene sulfide (PPS) in high frequency. Novel polyimide film containing 60% sulfide was synthesized through thermal imidization. The properties of these polyimide films morphology, thermal, dielectric characteristics and high frequency surface discharge lifetime, were studied. The films exhibited good thermal stability, having a mass loss less than 50% in decomposition temperature at 800 °C. The phenyl sulfide containing polyimide films showed a lower dielectric loss tangent and longer lifetime in the effect high frequency high voltage surface discharge. The novel polyimide is more suitable in the insulation application of high frequency power electronic devices.