Fabrication of covalently linked exfoliated boron nitride nanosheet/multi-walled carbon nanotube hybrid particles for thermal conductive composite materials

Boron nitride nanosheet (BNNS)/multi-walled carbon nanotube (MWCNT) hybrid particles were synthesized for use as a conductive filler for epoxy and polyphenylene sulfide (PPS). BNNSs were prepared via the exfoliation of bulk boron nitride (BN) particles. Micrometer-sized BN particles were exfoliated to form nanosheets, and their surfaces were modified using 3-aminopropyltriethoxysilane (APTES). The amine groups on the BNNS surface were reacted with acid-treated MWCNTs, and covalently connected BNNS/MWCNT particles were synthesized. Moreover, a chemical reaction without agitation increased the particle connection during the hybrid particle preparation, resulting in a large number of MWCNTs being introduced onto the BNNSs. The BNNS/MWCNT hybrid particle composite had better thermal conductivity than BNNSs or a BNNS/MWCNT composite without chemical bonding based on the same filler contents and composition. This was because of the particle connections establishing three-dimensional heat conducting path in a matrix, which affected the thermal conductivity of the composite.