Heat Transfer in BNNT-Polymer Nanocomposites from Non-equilibrium Molecular Dynamics

Doping high thermal conductivity fillers into polymers as a major way to improve the thermal conductivity of materials, but the failure mechanism of the coupling agents and entangled polymer chains on the thermal conductivity of nanofillers is missing. In order to explore those, the thermal conductivity of pure BN nanotube and BN nanotube with coupling agents was calculated by the nonequilibrium molecular dynamics method. It is shown that the thermal conductivity of BN nanotube with coupling agents decreased significantly at the full frequency range. The dynamical structural factor was calculated to exact the longitudinal acoustics mode of BNNT in the nanocomposites and found that the entangled polyethylene chains have little effect on the thermal conductivity of BNNT and the coupling agents are the main factor to destroy the thermal conductivity. Based on those results, a new branches method is proposed that the coupling agent should bond at the edge not on the surface for single-wall BNNT.