Synergetic Effect of Superparamagnetic Magnetite Nanoparticles and Multi Walled Carbon Nanotubes on the Thermal and Magnetic Properties of Polypropylene Nanocomposites

ABSTRACT Superparamagnetic (SPM) magnetite (Fe ₃ O ₄ ) nanoparticles and multi‐walled carbon nanotubes (MWCNTs) synergistic effects on the thermal and magnetic properties of isotactic polypropylene (iPP)‐based nanocomposites were investigated. The nanocomposites were produced by combining solution mixing and hot pressing techniques. Their structure, crystallization, thermal and magnetic behavior were examined using scanning electron microscopy (SEM), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and vibrating sample magnetometry (VSM). The results showed that incorporating 3% Fe ₃ O ₄ increased the 50% mass loss temperature of iPP from 359.8°C to 386.8°C. In comparison, adding 3% MWCNTs raised this temperature to 380.3°C. The addition of 10% MWCNTs increased the crystallization temperature by 23.5°C. This effect was attributed to their strong nucleating ability, which helps polymer chains align more efficiently. XRD analysis confirmed this trend. VSM measurements showed that saturation magnetization ( M _s ) decreased from 0.21 emu/g in iPP + 1% Fe ₃ O ₄ to 0.054 emu/g when MWCNTs were also present. This reduction was due to dilution of the magnetic phase, while SPM behavior remained dominant. The novelty of this work lies in systematically comparing how both fillers act synergistically when introduced by the same processing route into the iPP matrix. This study provides clear information about their combined influence on material properties. These nanocomposites show promise for applications in thermal management, magnetic sensing, electromagnetic shielding, and smart materials. These nanocomposites contribute to the development of systems designed for energy efficiency and advanced device performance.