Low‐Cost Polyethylene/Calcium Carbonate/Boron Nitride Composites With Highly Thermal Conductivity

The ongoing miniaturization, multifunctionalization, and integration of modern electronic devices lead to more and more heat generated. Therefore, developing thermal interface materials (TIMs) with high thermal conductivity (TC) is of great significance in effective thermal management. Polymers are selected for thermally conductive composites owing to their excellent properties, including stability and electrical insulation. However, achieving their high TC often requires adding a large amount of heat fillers to the polymer matrix, which inevitably increases costs. Thus, it remains a key challenge to develop polymer composites that simultaneously possess high TC and low cost. It is an effective approach to solve this problem by adding low‐cost mineral fillers. In this study, inexpensive and widely used calcium carbonate fillers were incorporated to fabricate low‐cost polyethylene/calcium carbonate/boron nitride (PE/CaCO 3 /BN) TIMs. The PE/CaCO 3 /BN composite (40/30/30, volume ratio) has a TC of 3.53 W/(m·K) and a tensile strength of 12.11 ± 2.30 MPa. Furthermore, the PE/CaCO 3 /BN composite also has good thermal stability; its TC decreases to 3.17 ± 0.09 W/(m·K) after 50 hot‐cold cycles, which is a reduction of 10.11% compared with that of the as‐prepared counterpart. This study offers an effective strategy to fabricate high thermally conductive composites at a low cost.