▎ 摘　　要

NOVELTY - Nano-cellulose thermally conductive composite film comprises nano-cellulose/graphene layers and nano-cellulose/dopamine modified boron nitride layers, alternately stacked in multiple layers, with high thermal conductivity, high insulation strength and excellent flexibility. The nanocellulose/graphene layer in the composite film is filled with graphene nanosheets in nanocellulose, where the filling amount of the graphene nanosheets is 5-10 wt.% of the total dry matter of the composite film. The nanocellulose/dopamine modified boron nitride layer is filled with boron nitride nanosheets in nanocellulose, where the filling amount of the boron nitride nanosheets is 5-10 wt.% of the total mass of the dry matter of the composite film. USE - As nano-cellulose thermally conductive composite film. ADVANTAGE - The composite film has high thermal conductivity, high insulation strength, excellent mechanical properties, and excellent flexibility, and meets the high-strength thermal management, insulation, extrusion resistance and other requirements of high-end chips and other electronic products. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the nano-cellulose thermally conductive composite film involving (a) adding the graphene nanosheets to deionized water, ultrasonically dispersing for 0.5-1 hour, and configuring graphene dispersion with a concentration of 1-5 mg/ml, adding the nanocellulose to deionized water, and ultrasonically dispersing for 0.5-1 hour to prepare a nanocellulose dispersion with a concentration of 1-5 mg/ml, processing the boron nitride in an ultrasonic bath, ultrasonically processing the boron nitride nanosheet for 10 hours and modifying the boron nitride nanosheet with dopamine, (b) uniformly mixing the nanocellulose dispersion and the graphene dispersion, blade coating the first layer of film, (c) uniformly mixing the nanocellulose dispersion and the dopamine-modified boron nitride nanosheets, layering on the first film by knife coating as the second film, (e) repeating the step (b) and step (c) alternately in turn until a laminated film with a set number of layers, and placing in an oven at 45 degrees C to evaporate and dry for 48 hours, when step (b) is repeated, producing subsequent odd-numbered films and when step (c) is repeated, producing subsequent even-numbered films and (f) hot-pressing the laminated film obtained in the step (e) to obtain a nano-cellulose thermally conductive composite film with a set number of layers and an alternate laminated structure.