Enhanced thermal conductivity of multilayered sheets of polyethylene and boron nitride via promoting molecular diffusion between layers

Abstract

In this work, we alternatively compressed a high density polyethylene/low molecular weight polyethylene (LMWPE)/hexagonal boron nitride (h-BN) composite layer and a low density polyethylene layer together to fabricate thermally conductive bulk products. Compared to our previous work (without the LMWPE component), introducing the short chain component, i.e., LMWPE, into the composite layers further enhanced the h-BN content to 18.3 vol. %, and, thus, more thermally conductive paths could be formed after annealing, resulting in higher thermal conduction performance. Also, the annealed multilayered cuboid in this work exhibited a high thermal conductivity of 1.96 (W/m K), 43% higher than that of our previous study (1.37 W/m K). In contrast with that of the samples with randomly distributed h-BN at the same loading, an approximately 145% enhancement was achieved. The results demonstrate that our method to fabricate the multilayered cuboids has a great opportunity for application in the thermal management field of electric devices.