Preparation of highly thermally conductive epoxy resin composites via hollow boron nitride microbeads with segregated structure

To meet the growing heat dissipation requirements of electronic devices, epoxy/boron nitride (BN) composites with high thermal conductivity, high thermal stability and low dielectric constant were prepared through a facile route. BN platelets were firstly stacked into hollow boron nitride microbeads (BNMB) via salt-template method; then, the as-prepared BNMB were further compressed and infiltrated with epoxy resin. Benefitted from the thermally conductive pathways formed by the shells of BNMB, the maximum thermal conductivity of epoxy/BNMB composites reached 17.61 W/m.K (in-plane direction) and 5.08 W/m.K (out-plane direction) at the BN loading of 65.6 vol%. In addition, the thermal stability has been improved significantly that the T-20 was increased by 227.3 degrees C compared to pure epoxy. Moreover, the dielectric constant (3.92) and dielectric loss (0.0209) were kept at a low level. This facile method provides a new insight to design highly thermally conductive composites for electronic packaging applications.