3D-network of hybrid epoxy-boron nitride microspheres leading to epoxy composites of high thermal conductivity

A facile and effective method has been developed to prepare highly thermal conductive composites with three-dimensional boron nitride (BN) network based on epoxy spheres (ESs). ESs synthesized and coated with fBN (ESs@fBN) were added into epoxy matrix to construct networks. The formation mechanism of ESs morphology and properties of composites with different content of ESs@fBN were investigated. The thermal conductivity of the composites was enhanced from 0.18 W m−1 K−1 of neat epoxy to 0.67 W m−1 K−1 of composite with only 7.4 wt% fBN. A 272% increment is attributed to the occupation of ESs, which can facilitate to form effective heat dissipating paths at low content of filler and improve the thermal conductivity of the composites. Moreover, the addition of reactive ESs and fBN could lead to an increase in storage modulus and Tg of epoxy resin. This method will give a new consideration for the preparation of thermally conductive composites.