A study of the mechanical performance of nanocomposites of polyethylene containing exfoliated boron nitride nanoplatelets

Abstract Boron nitride nanoplatelets (BNNPs) are emerging as a potential candidate for developing polymer‐based thermally conducting nanocomposites that have electrically insulating properties. Generally, the mechanical performance of such polymer‐based nanocomposites, for example, toughness, is often found to be inferior, primarily, owing to the poor dispersion of BNNP, resulting from weaker interfacial interactions between BNNPs and polymer matrices. Here, we report on a successful method to fabricate high density polyethylene (HDPE)/BNNP nanocomposites, with superior mechanical properties, through the in situ exfoliation of the nanofiller via a melt‐extrusion technique. The results obtained showed that the toughness of a nanocomposite with 15 wt% BNNP loading is 18.8 × 10 ³ KJ m ⁻³ , that is, about 1.5 times enhancement as compared to the control HDPE sample. The enhancement in mechanical properties can be attributed to a greater degree of homogeneous dispersion of the exfoliated BNNPs achieved using the melt‐ extrusion route. The results that were analyzed through scanning electron microscope and Fourier transform infrared measurements showed that an interesting microstructural feature, named “sunflower‐like” core‐shell structure, formed owing to the relatively stronger interactions between BNNPs and polyethylene chains, which in turn facilitated the uniform dispersion of exfoliated BNNPs in HDPE matrix. This work, therefore, opens up a pathway toward an easy and up‐scalable version for fabricating polymer nanocomposites that have superior mechanical performance and with wider applicability.