Enhanced dielectric properties of polypropylene composites via surface-modified boron nitride with amorphous carbon coating

As a petrochemical derivative, polypropylene finds widespread application in microelectronics and wireless communication. Developing polypropylene-based composites with enhanced dielectric performance and minimal loss is of great interest for capacitor dielectric applications. In this work, we propose a novel filler to optimize the dielectric properties of polypropylene. A thin amorphous carbon layer was coated onto boron nitride (BN) via glucose hydrothermal crosslinking, yielding BN@aC. Composites were then fabricated by melt blending polypropylene with varying concentrations of BN@aC. The influence of filler type (pristine BN vs. BN@aC) and loading on dielectric behavior was thoroughly examined. Notably, BN@aC outperformed pristine BN in enhancing dielectric performance. At 1 kHz and a low filler content of 1.5 wt%, the composite achieved a dielectric constant of 2.85 while maintaining an exceptionally low loss tangent of 3.04 × 10⁻³. Furthermore, given the thermal challenges associated with miniaturized electronic devices, the thermal stability of the composites was preliminarily assessed. This innovative BN@aC design provides a viable pathway for engineering dielectric materials with superior performance. Highlights: Preparation using glucose as a carbon source BN@aC core-shell structural materials. Improved the interface interaction between boron nitride and PP. BN@aC promotes an increase in the dielectric constant and a decrease in the dielectric loss of PP. Composites have good thermal properties.