Effect of alignment of h-BN platelets in LDPE disks on the thermal conductivity: Microstructure and modeling

In recent years, hexagonal boron nitride (h-BN) has gained significant attention due to its high thermal conductivity and low electrical conductivity, making it an attractive option for effective heat dissipation in electronic devices. This article specifically explores the impact of unidirectional alignment of h-BN platelets on the thermal conductivity of a low-density polyethylene matrix composite (LDPE/h-BN). The composite materials were fabricated by layering thin films, and various parameters, such as platelet size and film thickness, were systematically investigated. Additionally, dynamic mechanical behavior analysis (DMA) was conducted to assess the influence of incorporating h-BN particles on the dynamic mechanical properties of the composites. The study also involved modeling to enhance our understanding of the correlation between particle orientation and thermal conductivity. Regarding the difference between both h-BN and the use of different dies to elaborate the films, in-plane TC are relatively different because the orientation of the platelets in the final disk is highly influenced by both parameters. This alignment led to a remarkably high thermal conductivity value of 4.25 W/(m·K) with 50 wt% of h-BN 003. The study underscored the critical roles played by particle size and film thickness in achieving optimal thermal conductivity. Notably, this study stands out by avoiding the use of solvents during the composite development process, which sets it apart from approaches generally developed. • Length of the die in extrusion, to elaborate LDPE films play a crucial role in the orientation of the h-BN platelets. • Size of the h-BN platelets play a key role in their orientation in the film with LDPE. • Final orientation of the h-BN platelets (50 wt%) in disks can vary the in-plane thermal conductivity from 2.35 to 4.25 W/(m.K). • h-BN platelets orientation also has an influence on storage and loss modulus above 80 °C. • Heat transfer modeling reveals the presence of an interfacial thermal resistance.