Construction of 1D / 2D Boron Nitride Thermal Conductive Hybrid for Enhancing the Heat Transfer Performance of Polystyrene

ABSTRACT Employing thermally conductive fillers to construct polymer‐based composites is an effective approach to address the issue of poor thermal conductivity (TC) of polymer. Nevertheless, the low filler efficiency limits the TC enhancement. In this study, 1D/2D bridge‐type boron nitride microrods/boron nitride nanosheets (BNMR/BNNSs) hybrids were fabricated through a simple pyrolysis method. Subsequently, these hybrids were employed as fillers to prepare highly thermally conductive polystyrene (PS)‐based composites via an in situ polymerization strategy. The unique bridge‐type structure significantly enhances the contact probability and contact area between BNMRs and BNNSs, resulting in the superior heat transfer performance of PS/BNMR/BNNSs composites compared to PS/BNNSs and PS/BNMRs. Specifically, the TC value of the PS/BNMR/BNNSs composite containing 5 wt% BNMR/BNNSs hybrids is 3.55 W m ⁻¹ K ⁻¹ , 503% and 102% higher than that of PS/BNNSs (0.59 W m ⁻¹ K ⁻¹ ) and PS/BNRMs composites (1.76 W m ⁻¹ K ⁻¹ ), respectively. Additionally, the PS/BNMR/BNNSs composites possess outstanding heat transfer performance and exceptional dielectric properties. Consequently, our findings offer an effective strategy for designing highly thermally conductive composites for the thermal management of high‐power‐density electronics.