Interfacial thermal transport properties and its effect on thermal conductivity of functionalized BNNS/epoxy composites

• The thermal conductivity of functionalized BNNS and its interfacial thermal resistance with epoxy were calculated by molecular dynamics. • The mechanism of functionalization on reducing the interfacial thermal resistance of BNNS-epoxy was studied according to the phonon vibration density of state. • The influence of the BNNS content, size and functionalization rate on the thermal conductivity of composites was analyzed. • Under the synergistic effect of reduced BNNS thermal conductivity and enhanced BNNS-epoxy interfacial thermal conductance, there is a critical size for the effect of functionalized BNNS on the thermal conductivity of composite. The miniaturization and high-performance development of integrated circuits poses a major thermal challenge to microelectronic packaging, and there is an urgent need to study high thermal conductivity composites to improve the thermal management performance of high-power devices. In this paper, aiming at the thermal conductivity of BNNS/epoxy composites, the reverse non-equilibrium molecular dynamics method is used to study the effect of covalent and non-covalent functionalization on BNNS thermal conductivity and BNNS-epoxy interfacial thermal resistance. The strengthening mechanism of functionalization on interfacial thermal conductance is discussed according to phonon vibration density of states. And the effect of BNNS content, size, and functionalization rate on the thermal conductivity of composites is studied. The results found that the intrinsic thermal conductivity of BNNS reduced while the interfacial thermal conductance of BNNS-epoxy enhanced through functionalization. Under the synergistic effect of the two, there is a critical size for the effect of functionalized BNNS on the thermal conductivity of composite. When the BNNS is smaller than the critical size, functionalization can enhancing the thermal conductivity of the composite. The results can provide important theoretical guidance for the preparation of high thermal conductivity BNNS/epoxy composites.