Magnetic epoxy nanocomposites with superparamagnetic MnFe2O4 nanoparticles

Manganese iron oxide (MnFe2O4) nanoparticles successfully served as nanofillers for obtaining magnetic epoxy nanocomposites. The viscosities of MnFe2O4/epoxy resin liquid suspensions increased with increasing the nanoparticles loading except the suspension with 5.0 and 1.0 wt% loading, whose viscosities were lower than that of pure epoxy. The introduction of MnFe2O4 nanoparticles showed a lower onset decomposition temperature and glass transition temperature (Tg), which decreased with increasing the nanoparticles loading. The storage modulus and tensile strength of 1.0 wt% MnFe2O4/epoxy were a little higher than that of pure epoxy. The coercivity of MnFe2O4/epoxy nanocomposites with 5.0 wt% (44.7 Oe) and 10.0 wt% (43.9 Oe) displayed much higher than that of pure MnFe2O4 nanoparticles (14.94 Oe). The magnetic moment (m) of nanocomposites (1.354 μB for 10 wt% MnFe2O4/epoxy) are higher than that of pure MnFe2O4 nanoparticles (1.244 μB). The increased real permittivity observed in the nanocomposites was attributed to the interfacial polarization. The intrinsic permittivity of the MnFe2O4 nanoparticles was also calculated