Low-dielectric high-performance polyimide film as well as preparation method and application thereof

The invention provides a low-dielectric high-performance polyimide film as well as a preparation method and application thereof, diamino monomers with different volumes and acid anhydride are used for reacting to synthesize polyamide acid, then a ternary amine monomer is introduced to prepare micro-crosslinked polyamide acid, and micro-crosslinked polyimide is obtained through subsequent treatment. A ternary monomer or a crosslinkable polymer is introduced to form an intrinsic micro-crosslinking structure or an interpenetrating network structure to regulate and control the free volume of polyimide, the thermal expansion coefficient of polyimide can be effectively regulated and controlled, the mechanical property of polyimide can be improved, meanwhile, molecular chain movement can be effectively limited, and the dielectric loss of polyimide in a high-frequency wave band is reduced. Finally, the free volume of the polyimide is regulated and controlled and the mechanical property, the thermal expansion coeffici