Enhanced thermal conductivity of flexible h-BN/polyimide composites films with ethyl cellulose

The present work focuses on fabricating a flexible and thermally conductive PI composite film. The PI composite film was obtained by blending hexagonal boron nitride (h-BN) combined with ethyl cellulose and 2,2'-Bis(trifluoromethyl) benzidine (TFMB) functionalized GO (TFMB- GO) in polyimide (PI). The ethyl cellulose successfully formed the thermal conduction network by promoting the dispersion of h-BN in PI matrix. Thus, the thermal conductivity of the PI composite film with ethyl cellulose could be twice than PI film without ethyl cellulose. Besides, the PI composite film containing 30 wt% of h-BN could still exhibit excellent flexibility. Moreover, the combination of TFMB-GO could increase the tensile strength of the PI composite film by up to 80%. Overall, we provided a novel idea for the preparation of flexible substrate materials with efficient heat dissipation which was convenient and possible to apply widely in the industrial production.