Preparation and properties of branch‐leaf‐like polyimide composite films with high thermal conductivity and low dielectric loss

Abstract Polyimide (PI) is widely used in the communication field benefited from its low dielectric properties and good electrical insulating properties, however, its low thermal conductivity simultaneously limits its application in electronic packaging. Delayed heat dissipation can exacerbate the thermal stress generated by device operation to damage electronic structures, thereby affecting work efficiency. As a result, it is necessary to improve the thermal conductivity of polyimide and maintain excellent dielectric performance. Here, we demonstrate the polyimide (BPDA‐ODA) composites with ordered structure are prepared by filling commercial polyimides with aramid nanofibers connection nitrides greatly improve thermal conductivity and maintain the low dielectric loss. When the filling amount of SBN@CN is 30 wt%, the thermal conductivity increases to 1.162 W/mK, which is 8 times higher than that of pure PI (0.0147 W/mK). Moreover, thermal stability and mechanical properties are maintained, realizing that the dielectric constant is about 3.81 and the dielectric loss is as low as 0.0034 at 100 MHz, which endows a new insight for the application of polyimide in electronic packaging.