Improvement of thermomechanical and dielectric properties of thermoplastic polyurethane using bismuth sodium titanate/carbon nanotube hybrid fillers

Abstract

The development of innovative composite materials through the amalgamation of thermoplastic polyurethane (TPU) with bismuth sodium titanate (BNT) and carbon nanotube (CNT) fillers was investigated. Before the composite fabrication, the fillers' surfaces were treated to enhance their compatibility with the TPU matrix. Hybrid fillers of BNT and CNTs were fabricated by mixing the two types of filler particles through ball milling and subsequently annealing the mixture at 250°C. Melt-blending and injection molding were utilized to synthesize the composites at 210°C processing temperature. The prepared composites showed significantly enhanced thermal conductivity, dielectric constant, thermal stability, and thermomechanical properties compared with the neat TPU matrix. For instance, the dielectric constant was enhanced by 340% upon the inclusion of 40 wt.% BNT and CNT fillers compared to the neat TPU matrix (40CBNT-TPU has 13.2). In particular, the inclusion of BNT-CNT particles in the TPU matrix improved the thermal conductivity of the TPU matrix by 1180% tremendously as compared to neat TPU (40CBNT-TPU has 2.6 W/(m.K)). Highlights: Crystalline bismuth sodium titanate (BNT) is fabricated. Degradation of 8 wt.% of the IPDI-treated BNT proves surface treatment. Dielectric constant (DC) improved by 340% compared to neat TPU. Thermal conductivity (TC) enhanced 11.4 times compared to neat TPU. Improvement in TC and DC will make it applicable in electronic materials. © 2024 Society of Plastics Engineers.