Mussel inspired interfacial modification of boron nitride/carbon nanotubes hybrid fillers for epoxy composites with improved thermal conductivity and electrical insulation properties

Epoxy resin is widely used in various industrial fields due to its good adhesion, corrosion resistance and the like, but its thermal conductivity is low and it is difficult to meet the heat dissipation requirements. In order to obtain epoxy composites with high thermal conductivity and excellent electrical insulation, an effective method for functionalizing boron nitride (BN) and multi-walled carbon nanotubes (CNTs) is proposed. The BN and CNTs were first ultrasonically mixed, and then functionalized by a simple dip coating procedure with polydopamine (PDA) coating (named as m(BN/CNT)). Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy analysis demonstrated the successful functionalization of PDA on BN and CNTs surfaces. Adding 20 vol% m(BN10/CNT1) increased the thermal conductivity of the epoxy composite by 231% compared to pure epoxy matrix, while still maintained a volume resistivity above 1014 Ω·cm. Dynamic mechanical analysis and scanning electron microscopy showed that PDA functionalization improved the interfacial interaction between BN, CNTs and the matrix, thus ensuring the improved thermal and mechanical properties.