Significantly enhanced thermally conductive epoxy composite composed of caterpillar-like structured expanded graphite/ boron nitride nanotubes

Abstract

The trend toward miniaturization, integration and multifunctionality of modern electronics has led to a rapid increase in power density, which makes heat dissipation a critical issue. Despite the great potential of graphite-related nanocomposites in dissipating excess heat to ensure high efficiency and long lifetime of electronic devices, the practical application of these composites is limited by the ultra-low vertical thermal conductivity due to the interfacial thermal resistance between graphite layers. Here, a caterpillar-like hybrid filler was fabricated by the in situ intercalation of boron nitride nanotubes (BNNTs) between expanded graphite (EG) layers based on chemical vapor deposition technology. Owing to the optimized interfacial thermal resistance by forming covalent C-N bonding at the interface of EG and BNNT, the through-plane thermal conductivity of epoxy-based nanocomposites can be up to 5.18 Wm−1 K−1. In addition, the composite possessed electromagnetic interference shielding performance of 33.34 dB while maintaining electrical insulation due to the hierarchical structure. This work provided a new strategy for fabricating polymer-based composites with excellent through-plane thermal conductivity in thermal management applications.

Optimization of mechanical and electromagnetic interference shielding properties of expanded graphite/polyurethane composite foams

“…Menghan et al used a chemical vapor deposition method to intercalate graphite with boron nitride nanotubes. 20 The composite exhibited an excellent EMI SE (À33.34 dB) while maintaining electrical insulation due to its hierarchical structure. However, they did not provide any details regarding the mechanical properties of the composite.…”

“…However, that study did not report the thickness of the prepared composite nor crucial information such as transmission loss. Menghan et al used a chemical vapor deposition method to intercalate graphite with boron nitride nanotubes 20 . The composite exhibited an excellent EMI SE (−33.34 dB) while maintaining electrical insulation due to its hierarchical structure.…”

Role of four-phonon processes in thermal conductivity of two-dimensional materials and thermal-transport enhancement arising from interconnected nanofiller networks in polymer/nanofiller composites

“…Interconnected filler networks can be achieved by a wide range of techniques such as foams and aerogels [24][25][26] and ice-templating. 27 Expanded graphite [28][29][30] provides another efficient pathway for achieving high k composites through a network of interconnected graphene nanosheets. Interlinked filler networks have also been achieved by coating polymer pellets with nanofiller material followed by hot pressing.…”