▎ 摘　　要

NOVELTY - Film comprises a polyimide comprising polymer reaction product of diamine monomer and dianhydride monomer. The diamine monomer comprises N,N-bis(4-aminophenyl)-N, N-diphenyl-1,4-phenylenediamine. USE - The film is useful in a graphite film (claimed) is useful as radiating material of an electronic product and in a heat-assisted magnetic resonance imaging (HAMR) device. ADVANTAGE - The film prepares graphite film with high thickness, high cyclization degree, high carbon residue rate, high heat resistance, and high carbon content so that the thickness change of the graphitized polyimides film after calendering is small. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) Graphite film prepared by carbonizing and graphitizing the film; and (2) preparing film, comprising (a) adding the diamine monomer, the dianhydride monomer and the catalyst into the organic solvent, and stirring to reaction under nitrogen protection to obtain a polyamic acid solution; (b) carrying out imidization treatment on the polyamic acid solution to obtain the polyimide solution, coating the polyimide solution on a support plate to obtain a polyimide coating film, baking and curing.