▎ 摘　　要

NOVELTY - High heat-conducting four-needle-shaped composite particle/polyimide film comprises 1-60 pts. wt. a heat-conducting filler, 1-5 pts. wt. surfactant and 50-600 pts. wt. polyamic acid solution. The heat conducting filler is the graphene welding boron nitride coated tetrapod-shaped zinc oxide composite particle prepared by electrostatic self- assembling method. USE - The high heat-conducting four-needle-shaped composite particle/polyimide film is useful in electronic materials e.g. thermal management materials and interface materials. ADVANTAGE - The film: has high thermal conductivity and electrical insulation; and preparation process is simple and has short molding cycle. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing high heat-conducting four-needle-shaped composite particle/polyimide film, comprising (i) preparing the dispersion with 1-80% absolute ethanol and deionized water, adding 1-10% surfactant slowly into the dispersion, stirring to dissolve, adding 5-80% four needles of zinc oxide, heating and stirring in a water bath, filtering and drying to prepare zinc oxide modified with surfactant; (ii) taking the hexagonal boron nitride, calcining it at 900-1200 degrees C for 1-4 hours, using deionized water as the dispersion liquid, filtering and drying after sonication to obtain modified boron nitride; (iii) taking the modified boron nitride and the modified zinc oxide at mass ratio of 1:1-10, taking the modified boron nitride, adding deionized water to configure 1-10 mg/ml boron nitride dispersion, adding into step (i) after sonication to prepare zinc oxide modified with surfactant, stirring, filtering and drying to prepare a four-needle thermal conductive filler coated with boron nitride and zinc oxide; (iv) taking graphene oxide and boron nitride coated zinc oxide composite particles at mass ratio of 0.5-1:10, taking graphene oxide, adding deionized water to configure 1-10 mg/ml graphene oxide dispersion, adding into step (iii) after sonication to prepare boron nitride-coated zinc oxide composite particles, stirring, filtering and drying to obtain graphene oxide welded boron nitride coated zinc oxide four-needle thermal conductive filler; (v) dispersing the boron nitride evenly in an organic solvent, adding diamine to dissolve it and adding dibasic anhydride into the solution for in-situ polymerization to prepare a polyamic acid solution containing boron nitride; (vi) adding the graphene oxide welded boron nitride coated zinc oxide thermally conductive filler prepared into the boron nitride polyamide solution prepared, stirring uniformly and carrying out vacuum defoaming treatment; and (vii) laying the film with the polyamic acid solution that has been defoamed, and heating the imidization of the laid film and cooling.