Thermal and dielectric properties of epoxy resin filled with double-layer surface-modified boron nitride nanosheets

Highlights: • Grafting DA at the end of KH560 is firstly proposed to functionalize BNNSs. • Thermal conductivity and electrical properties of DKBP are enhanced significantly. • Improvement mechanism is explored by molecular dynamics simulation. • This method improves transfer effect and reduces scattering effect at the interface. Owing to the rapid development of advanced power system and modern micro-electronic devices, exploiting composites with excellent thermal conductivity and dielectric properties has become increasingly important. In this work, a double-layer surface modification method of grafting dopamine (DA) at the end of 3-glycidoxypropyl-trimethoxysilane (KH560) is firstly proposed to modify the surface of boron nitride nanosheet (BNNS), for improving the thermal conductivity and dielectric properties of epoxy resin (EP). Besides, the thermal conductivity of EP composites with double-layer surface-modified BNNSs and its improvement mechanism is explored with molecular dynamics (MD) simulation from micro level. The results illustrate that thermal conductivity of EP composites doped with double-layer modified BNNSs by grafting DA at the end of KH560 (DKBP) is 0.252 W/(m·K), 129% higher than EP. Moreover, this double-layer surface modification method of DKBP is beneficial to enhance the heat transfer effect and reduce scattering effect at the interface, which is the essential reasons for improving thermal conductivity of composites. Meanwhile, DKBP composite also presents superior dielectric properties. This work provides a promising idea to develop new insulating materials with high thermal conductivity.