▎ 摘　　要

NOVELTY - Graphene electrothermal composite film having safety voltage of 6 V, comprises 10-100 pts. wt. reduced graphene oxide, 1-10 pts. wt. carboxylated carbon nanotubes, 1-15 pts. wt. polyvinyl alcohol and 0.01-1 pts. wt. silane coupling agent; polyvinyl alcohol polymers with hydroxy groups in the side chains are used for compounding to form a graphene-carbon nanotube composite film having a network structure. USE - The graphene electrothermal composite film is useful in the high performance flexible electrothermal film and technical field. ADVANTAGE - The graphene electrothermal composite film has high electrical conductivity, high thermal conductivity, high heat dissipation performance, excellent flexibility, excellent temperature stability, and can perform electrothermal work at a safe voltage of 6 volts. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing graphene electrothermal composite film having safety voltage of 6 V, comprising (i) dispersing reduced graphene oxide powder and silane coupling agent in dehydrated alcohol, mixing, ultrasonically treating for 5-30 minutes to obtain a modified graphene dispersion, adding carboxylated carbon nanotubes to the modified graphene dispersion, heating and stirring for 0.5-2 hours to obtain graphene-carbon nanotube composite dispersion, drying and evaporating at 30-100 ℃ for self-assembly until viscous slurry A is obtained, (ii) dissolving polyvinyl alcohol in pure water, adding it to the slurry A obtained in step (i), ultrasonically treating for 5-30 minutes, heating and stirring for 0.5-2 hours to obtain graphene, carbon nanotube and polyvinyl alcohol composite dispersion, drying and evaporating at 30-100 ℃ until viscous slurry B is obtained, (iii) pouring the slurry B obtained in step (ii) into container coated with release agent, the upper opening fully contacts with the air, and the lower part is smooth and flat, drying, evaporating at 30-100 ℃, and peeling off from the container to obtain a composite film of graphene, carbon nanotubes and polyvinyl alcohol, and (iv) calendering the composite film obtained in step (iii) at 25-100 ℃ under a pressure of 5-50 MPa to obtain a graphene electrothermal composite film.