The invention relates to a
polyimide composite film for realizing high-dispersion carbon nanotubes through chemical anchoring and a preparation method of the
polyimide composite film, which are used for solving the problems that carbon nanotubes in the existing
carbon nanotube /
polyimide composite material are easy to
agglomerate, poor in interfacial compatibility and low in
grafting efficiency. The preparation method comprises the following steps: S1, ultrasonically dispersing aminated carbon nanotubes in
anhydrous dimethylacetamide to obtain a stable dispersion liquid; s2, slowly dropwise adding
pyromellitic dianhydride into the stable dispersion liquid under an ice bath condition, and enabling the
pyromellitic dianhydride to react with the aminated carbon nanotubes under the assistance of
triethylamine to form anchor points; s3, adding a
diamine monomer 4, 4 '-
diaminodiphenyl ether, and gradually adding the residual
pyromellitic dianhydride to carry out in-situ
polymerization; and S4, preparing a wet film by adopting a
curtain coating or
spin coating method, and carrying out step-by-step thermal imidization at 80-300 DEG C to obtain the covalent
composite film. Controllable covalent connection of the carbon nanotubes and pure polyimide chain segments can be achieved on the
molecular level, and therefore the composite film with excellent heat
conductivity,
electromagnetic shielding performance and mechanical performance is obtained.