▎ 摘　　要

NOVELTY - Preparation of a polyimide-based high-heat-conductive graphite nanofiber film involves preparing a polyimide precursor-polyamic acid glue solution using a dibasic anhydride and a dibasic amine monomer as raw material by solution polycondensation in a solvent, adding graphene and metal oxide to the glue solution, and stirring well, electrospinning the polyamic acid glue solution containing graphene and metal oxide to form a polyamic acid fiber film, calendaring, subjecting to impregnation treatment, subjecting the partially-imidized fiber film to biaxial stretching chemical imidization treatment to obtain a polyimide fiber film with a three-dimensional crosslinked structure, carbonizing the three-dimensional crosslinked polyimide fiber membrane, cooling to room temperature to obtain a polyimide-based carbon fiber film, graphitizing the polyimide-based carbon fiber film in a graphitization furnace protected by flowing argon, and cooling to room temperature. USE - Preparation of polyimide-based high-heat-conductive graphite nanofiber film used for aerospace application, microelectronic application, separating film, and laser application. ADVANTAGE - The method produces polyimide-based high-heat-conductive graphite nanofiber film with high mechanical strength, flexibility, and thermal conductivity. DETAILED DESCRIPTION - Preparation of a polyimide-based high-heat-conductive graphite nanofiber film involves preparing a polyimide precursor-polyamic acid glue solution using a dibasic anhydride and a dibasic amine monomer as raw material by solution polycondensation in a solvent, adding graphene and metal oxide to the glue solution, and stirring well, electrospinning the polyamic acid glue solution containing graphene and metal oxide with a solid content of 5-25% to form a polyamic acid fiber film containing graphene and metal oxide, calendaring the polyamic acid fiber film containing graphene and metal oxide in a precision calendar, sending the calendered polyamic acid fiber film into a chemical imidization mixed solvent comprising a dehydrating agent, a catalyst, and a solvent, and soaking for 60-300 seconds for impregnation treatment, partial chemical imidizing the soaked calendered polyamic acid fiber film through three temperature sections of 40°C, 60°C and 80°C each for 1-10 minutes, subjecting the partially-imidized fiber film containing graphene and metal oxide to biaxial stretching chemical imidization treatment at 350-420°C for 0-1 hours to obtain a polyimide fiber film with a three-dimensional crosslinked structure, carbonizing the three-dimensional crosslinked polyimide fiber membrane in a carbonization furnace with an absolute pressure of 1-5 Pa according to following program temperature control: the heating rate of 1-6℃/min is increased to 480-500℃ and the temperature is maintained for 0.5-1 hour, the heating rate of 0.5-2℃/min is increased to 600-650℃ and the temperature is maintained for 0.5-1 hours, and the heating rate of 1-3℃/minute is increased to 1000-1400℃ and the temperature is kept for 0.5-1 hour, cooling to room temperature to obtain a polyimide-based carbon fiber film, graphitizing the polyimide-based carbon fiber film according to the following program temperature control in a graphitization furnace protected by flowing argon: the heating rate of 20°C/minute is increased to 1000°C, the heating rate of 4-6℃/minute is increased to 1800-2000℃ and the temperature is maintained for 0.5-1 hour, and the heating rate of 3-5℃/minute is increased to 2700-2850℃ and the temperature is maintained for 0.5-1 hours, and cooling to room temperature.