Self-constructing thermal conductive filler network via reaction-induced phase separation in BNNSs/epoxy/polyetherimide composites

An effective and facile method was developed to construct the thermal conductive path way in BNNSs-NH2/epoxy/polyetherimide (PEI) ternary blends via reaction-induced phase separation (RIPS). The well dispersed BNNSs-NH2 in the blends was prepared by the urea-functionalization process, which built a bridge to each other at the interface between epoxy and PEI phases. The through-plane thermal conductivity (TC) of composites is enhanced by 83% at low content of 1 wt% BNNSs-NH2. Filler thermal conductive efficiency (eta) of BNNSs-NH2 reaches 189 and 83 based on volume fraction and weight fraction, respectively. In addition, the BNNSs-NH2 shows a critical impact on the kinetic of RIPS, which promotes the curing reaction (coarsening process) of epoxy phase. The glass transition temperatures (T-g) of epoxy and PEI were both enhanced due to the amino group of BNNSs and its selective distribution.