Experimental and atomistic insight on the thermal transport properties of h-BN/high density polyethylene nanocomposite

Abstract

The article investigates the effect of hexagonal boron nitride nanosheet (BNNS) on the thermal transport properties of high density polyethylene (PE) based nanocomposites. An experimental approach was adopted to investigate the effect of the concentration of boron nitride nanoplatelets (BNNP) on thermal conductivity, whereas an atomistic approach was utilized to study the governing mechanism for interfacial thermal conductance (ITC) in BNNS/PE nanocomposites. It was reported from experiments performed using a hot disc analyzer that PE's thermal conductivity improves up to 29.6% with 7wt.% of BNNP. Large dimension nanosheet grown using chemical vapor deposition based techniques are polycrystalline. In continuation with experimental characterization, ITC in mono-crystal and bi-crystal BNNS reinforced PE nanocomposites was predicted using atomistic simulations. It was concluded from the reverse non equilibrium molecular dynamics based simulations that bi-crystalline BNNS with higher mis-orientation angle have superior reinforcing capabilities to improve thermal transport properties. Based on structures of dislocations at the grain boundaries (GB), ITC values were predicted. Depending on the two crystals' alignment, GB configurations can be either nitrogen-rich (N-N) or boron-rich (B-B). It was predicted from the simulations that higher energy nitrogen-rich GBs are better aligned with the PE chains that enhance ITC values.