Polyimide Composites with Fluorinated Graphene and Functionalized Boron Nitride Nanosheets for Heat Dissipation

Polyimide (PI) with excellent comprehensive properties has been extensively applied in electronic devices. The miniaturization and integration of electrical equipment put forward more stringent requirements for heat dissipation, so a composite with high thermal conductivity and low dielectric properties has become a critical factor. In this work, fluorinated graphene (FG) and boron nitride nanosheets modified with polydopamine (PDA@BNNS) were filled into the PI matrix as fillers to prepare FG/PDA@BNNS/PI composites. The mixed filling of FG and BNNS synergistically improves the dielectric and thermal conductivity, and this research breaks the balance barrier between dielectric and thermal conductivity. The resulting 4.99 wt % FG/PDA@BNNS/PI composite exhibited excellent comprehensive properties, including ultralow dielectric constant of 1.67, low loss of 0.013 at 1 MHz, and high thermal conductivity of 2.464 W m–1 K–1. In addition, the film also showed standout breakdown resistance (81.22 kV/mm) and mechanical properties such that the tensile strength reached 35.7 MPa. This report can inspire future development of composites for electronic packaging.