Thermal Conductivity and Mechanical Properties of Thermoplastic Polyurethane-/Silane-Modified Al2O3 Composite Fabricated via Melt Compounding

The increase of miniaturization and rise of powerhouses has caused a need for high-performing thermal interface materials (TIMs) that can transfer heat in electronic packaging. In this study, a thermoplastic polyurethane (PU)/alumina composite was produced via twin extrusion and was suggested as a TIM. The surfaces of the alumina particles were modified by gamma- aminopropyltriethoxysilane (APTES) and then evaluated using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The field emission scanning electron microscopy (FE-SEM) images revealed that the addition of surface-modified alumina was well adhered in the PU matrix. The tensile strength of the composite remained unchanged, while the Young's modulus showed improvement as compared to the pure PU. The elongation at the break decreased as the filler loading increased, due to the brittle behavior of the composite. The viscoelastic elastic property analysis results revealed that there was an increase in the storage modulus of the composite and the glass transition temperature curve shifted to the right. The thermal conductivity of the composite showed that there was an 80.6% improvement in thermal conductivity with the incorporation of 40% APTES-treated alumina particles.