Constructing a parallel aligned shish kebab structure of HDPE/BN composites: Toward improved two-way thermal conductivity and tensile strength

Abstract

Inspired by the clam-shell structure of pearls, we fabricated thermally conductive high-density polyethylene (HDPE) reinforced by a 2D filler, boron nitride (BN). SEM images showed only lamellae randomly distributed in unshared HDPE samples, whereas a shish-kebab structure was introduced by utilizing an in-house designed rotational shear system. XRD results indicate the BN (002) plane is parallel to the sheared direction. Due to the interconnected shish-kebab structure and aligned BN (002) plane, the Vicat softening temperature was increased from 82.8 °C to 107.9 °C, demonstrating excellent heat resistance under high temperatures. An optimal thermal conductivity of 1.26 W/mK was found at 35 vol% BN loading with a tensile strength of 40 MPa. This work has utilized external force to manufacture HDPE/BN composites with effective thermal dissipation and higher service temperature. The excellent thermo-mechanical properties mean a longer service time and less replaced frequency of material under extreme operating conditions.