In order to improve the comprehensive performance of Polyimide(PI) film in practice

the comparison tests were conducted to study the effectsof graphene oxide and Al2O3 nanoparticles on the performance of PI films. Onegroup added Al2O3 particles with mass fractions of 0%

0.5%

and 1% to the PIfilm. The other group added graphene oxide with mass fractions of 0.2%

0.4%

0.6%

0.8%

and 1% to the 1% Al2O3/PI film. The thermal stability

tensilestrength

fracture morphology

dielectric spectrum

and breakdown fieldstrength of the different composition films were characterized. The resultsshow that the increase of Al2O3 nanoparticle content in PI leads to asignificant decrease in the thermal stability of the film above 400 °C. Theaddition of graphene oxide can significantly improve the thermal stability ofAl2O3/PI film. The addition of γAl2O3 can increase the mechanical properties ofthe composite film. The addition of graphene oxide increases the dielectricconstant of the composite film

but has little effect on the electricalconductivity of the film. The dielectric loss tangent of the film decreasesfirst and then increases with the increase of graphene oxide content

and it isthe smallest when the graphene oxide mass fraction is 0.6%. In addition

theaddition of graphene oxide significantly improves the breakdown field strengthof the Al2O3/PI film.