Magnetic high density polyethylene nanocomposites reinforced with in-situ synthesized Fe@FeO core-shell nanoparticles

Magnetic high density polyethylene (HDPE) polymer nanocomposites (PNCs) with different loadings of iron@iron oxide core-shell nanoparticles (NPs) were fabricated by in-situ thermal decomposition of organometallic iron precursors in the HDPE-xylene solution. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) measurement indicated that the HDPE chains were physically adsorbed onto the surface of NPs instead of forming chemical bonding during the formation of these PNCs. Transmission electron microscopy (TEM) micrographs revealed that the iron core NPs surrounded with iron oxide shell were formed in the HDPE hosting matrix with good dispersion, an inter-network structure was formed when the particle loading reached 10.0 wt%. Mössbauer spectrum analysis showed that the oxidization content of the iron NPs decreased with increasing the particle loading. The X-ray diffraction (XRD) analysis and differential scanning calorimetry (DSC) characterization demonstrated that the crystalline structure of HDPE matrix was not influenced by the incorporation of the NPs; however, fusion heat and crystalline fraction of the HDPE matrix decreased with the introduction of these NPs. The melt rheological behaviors were significantly changed as indicated by different complex viscosities, storage moduli and loss moduli between pristine HDPE and its PNCs. Magnetic property investigation revealed a soft ferromagnetic behavior for these HDPE PNCs at room temperature and the coercivity was decreased with increasing the particle loading. Thermal gravimetric analysis (TGA) demonstrated that the thermal stability of these HDPE PNCs was enhanced in the presence of the NPs. Dielectric properties of the HDPE PNCs were also investigated and discussed in detail.