Higher thermal conductivity and mechanical enhancements in hybrid 2D polymer nanocomposites

Abstract

Nanocomposites based on graphene oxide (GO), hexagonal boron nitride (h-BN), and their hybrid GO/h-BN as nanofillers in polyurethane (PU) were prepared, and their structures and morphologies were studied. The efficient production of a few layers of nanofillers was completed using the direct liquid-phase exfoliation process. Mechanical and thermal tests were carried out to study the effect of the addition of GO, h-BN, and GO/h-BN at different wt% in the PU system. The tensile strength and Young's modulus showed an increase of up to 85% and 140%, respectively, for the composite containing 0.5 wt% of the hybrid GO/h-BN mixture. An impressive improvement of up to ~1450% in thermal conductivity was observed for the same sample when compared to neat polymer. In order to gain further insights regarding the mechanism behind the nanofiller dispersion and adhesion processes in PU, fully atomistic classical molecular dynamics simulations were carried out. Based on these simulations, it was possible to build structural models that help to explain the thermal and mechanical improvements in the hybrid GO/h-BN composites, with a focus on its stabilization energy.