Fabrication of high dielectric properties and higher thermal conductivity thermoplastic polyurethane composites with CNT-covered SrTiO3

Abstract

Our study aims to fabricate a high dielectric constant and suitable thermal conductivity without influencing the mechanical properties of composites of thermoplastic polyurethane (TPU) with carbon nanotube (CNT)-covered strontium titanate (SrTiO3). Initially, the CNT particles were functionalized with surface treatment using aminopropyl tri-ethoxy silane (APTES) following nitric acid (HNO3) and sulfuric acid (H2SO4) treatments of CNT particles. The functionalized CNT was covered on the SrTiO3 particles through the hydrothermal reaction process. The composites of TPU and CNT-covered SrTiO3 were fabricated via melt-extrusion methods. Analysis of dielectric constant, thermal conductivity, mechanical properties, thermal degradation were performed to investigate the composites’ capabilities. We found that the dielectric constants of the composites with the application of 40% CNT-covered SrTiO3 were three times (300%) the neat TPU matrix. The tensile strength was only minimally affected; the thermal degradation nature reveals that the thermal stability of the composites was maintained compared with the neat TPU. The thermal conductivity has improved significantly about 9 times (improved from 0.21 to 1.84 W/(m*K) compared with the neat TPU with the application of 40% CNT-covered SrTiO3.