Synergetic effects in hybrid hexagonal boron nitride/high thermal conductive graphite reinforced polypropylene composites for advanced thermal applications

Abstract

Effective thermal management has become crucial for the performance and reliability of miniaturized electronic devices. While high filler loading improves heat dissipation, it often compromises other essential properties. Therefore, hybrid fillers combining distinct functionalities offer promising alternatives. In this study, we investigated the mechanical, electrical, and thermal properties of polypropylene (PP) composites reinforced with a novel hybrid filler consisting of hexagonal boron nitride (hBN) and high conductive graphite (Gr). The influence of filler ratios and the use of maleic anhydride grafted polypropylene (MaPP) as a compatibilizer are systematically explored. The results showed that the addition of hBN enhanced both tensile and flexural modulus as well as the thermal stability. The addition of 10 wt% hBN and 20 wt% graphite, along with 3 wt% MaPP, enhanced the tensile modulus of polypropylene composites from 2000 MPa to 2475 MPa and increased thermal conductivity from 0.32 W/m·K to 0.51 W/m·K. Additionally, while graphite reduced surface electrical resistivity from ∼10¹⁵ to ∼10⁸ Ω/sq, MaPP moderately mitigated this effect by disrupting conductive pathways.