Preparation And Properties Of Conductive Polyimide Composite Film

Because of the excellent performance, polyimide(PI) has been widely used in various high-tech fields. But the insulation of PI limits its application in the conductive area. Therefore, in order to improve the shortcoming, polyimide should be modified to increase its conductivity, while keeping the other excellent performance, broaden its applications.The purpose of this paper is to increase the conductivity of the polyimide, and to explore the filler added to the polyimide on other aspects of performance. This paper mainly discussed and researched about the follow aspects: First, the high viscosity polyamide acid(PAA) was first synthesized, which is in order to make sure the PI film has excellent mechanical performance; Second, by in situ polymerization, a series of different content of conductive flake nickel powder(CFNP) of CFNP/PI composite films were prepared and theirs performance were studied; Third, in order to choose a better packing and its best content, KH550 and NDZ-401 were selected to modify the conductive chain nickel powder(CCNP); Forth, different modified conductive chain nickel powder(MCCNP) content of MCCNP/PI composite films was prepared, the relevant performance of them were studied and them were compared with CFNP/PI composite films.There were four conclusions. First, the molar ratio of Weighing anhydride and amine was controlled in 1.000:1 ~ 1.010:1, so excellent mechanical properties of PI film could be obtained; Second, when CFNP mass fraction was 21.5%, the volume resistivity of PI/CFNP composite films dipped to 3.55×108Ω?cm, which reached the percolation threshold, at the same time, the conductivity performance of it had improved significantly, reaching antistatic effect, excellent thermal performance, and the overall performance was best; Third, 0.8% NDZ-401 is used as a modifier, the dispersion effect of CCNP is best; Forth, when modified CCNP mass fraction was 21.5%, the volume resistivity of modified CCNP/PI composite films dipped to 6.17×107Ω?cm, which reached the percolation threshold. Compared with CFNP, modified CCNP has a lower percolation threshold in the composite film.In summary, when the mass fraction of MCCNP was 17.5%, the performance of the conductive PI composite film was the best. Obtained modified CCNP/PI composite film had excellent antistatic effect, thermal performance. At the same time, the mechanical properties of the composite film also maintained at an optimal level. This composite film can be used as high-temperature electromagnetic shielding film to apply in the electronics, aerospace and other fields.