Curing epoxy with polyvinylpyrrolidone (PVP) surface-functionalized MnxFe3-xO4 magnetic nanoparticles

Poor, Good, and Excellent are labels for thermoset composites cured at a given heating rate applied in nonisothermal differential scanning calorimetry (DSC). Here the potential of surface- and bulk-surface functionalized nanoparticles to curing with epoxy has been unraveled. Cathodic electrodeposition technique was used to yield three types of magnetic iron oxides (MIOs): MIOs, polyvinylpyrrolidone (PVP) surface-functionalized MIOs (PVP/MIOs), and PVP/MIOs in which Mn2+ cations were partially doped in (Mn-doped PVP/MIOs). The resulting nanoparticles were characterized for surface by Fourier-transform infrared spectroscopy (FTIR), for size and size distribution by field-emission scanning electron microscopy (FE-SEM), for bulk composition by X-Ray diffraction (RXD) and for supermagnetic properties by vibrating sample magnetometry (VSM). Epoxy nanocomposites containing 0.1 wt.% of PVP/MIOs and Mn-doped PVP/MIOs underwent nonisothermal DSC at four heating rates. Curing epoxy with PVP/MIOs and Mn-doped PVP/MIOs was qualified by Cure Index, which demonstrated the effect of bulk and surface modification of MIOs. Overall, Good cure was the case for epoxy nanocomposites containing Mn-doped PVP/MIOs due to accelerating effect of PVP and Mn2+ on crosslinking between epoxy and amine.