Functionalized Graphene‐Reinforced Thermoplastic Polyurethane Nanocomposites: Thermomechanical and Magnetic Properties

Abstract

Polymeric nanocomposites have attracted significant interest for their low density, processability, and multifunctional properties, making them suitable for applications such as flexible electronics, sensors, biomedical devices, and functional coatings. In this work, thermoplastic polyurethane (TPU) nanocomposites reinforced with thermally reduced graphene oxide (TrGO) functionalized with nickel (Ni) and cobalt (Co) nanoparticles were developed via melt blending in a twin‐screw extruder and systematically characterized. Structural analyses using Raman spectroscopy, X‐ray diffraction (XRD), and scanning electron microscopy (SEM) confirmed successful TrGO functionalization and the formation of ordered lamellar structures. Thermogravimetric analysis (TGA) indicated that incorporating the nanofillers did not significantly affect the thermal stability or phase‐transition behavior of TPU. Dynamic mechanical analysis (DMA) revealed increased stiffness below the glass transition temperature, demonstrating effective reinforcement of the polymer matrix. Tensile testing showed substantial improvements in mechanical performance, with increases of up to 145% in tensile strength and 146% in elongation at break compared with neat TPU. Rheological measurements indicated higher viscosity and enhanced pseudoplastic behavior, suggesting strong polymer‐filler interactions. Magnetic characterization revealed weak ferromagnetic contributions in the Ni‐ and Co‐functionalized systems. These results demonstrate that metal‐functionalized TrGO is an effective multifunctional filler for TPU, providing significant mechanical reinforcement while maintaining thermal stability, with potential applications in flexible electronics, smart coatings, and advanced polymeric devices.