۱- Introduction

۲- Experimental

۳- Results and discussion

۴- Conclusion

References

Abstract

In this work, the bulk and surface composition of Fe3O4 supermagnetic nanoparticles were modified for efficient epoxy curing. The bare, ethylenediaminetetraacetic acid (EDTA) capped, and cobalt (Co)-doped EDTA capped Fe3O4 nanoparticles were synthesized electrochemically. The crystalline structure and phase information, surface capping, morphology and magnetization behavior of nanoparticles were studied by X-Ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM) and vibrating sample magnetometer (VSM), respectively. A low amount of the prepared nanoparticle (0.1 wt.%) was used in preparation of epoxy nanocomposites. Nonisothermal differential scanning calorimetry (DSC) under different heating rates was performed to study the potential of nanoparticles in curing epoxy resin with an aliphatic amine. The heat release data on nanocomposites suggest that EDTA capped Co-doped Fe3O4 considerably improved the curing reaction between epoxy resin and the curing agent. Calculations based on Cure Index approved qualitatively a shift from Poor to Good cure by concurrent lattice and surface modifications of magnetic nanoparticles. It is bielived that the approach used in this work can pave the way to enhance curability of epoxy nanocomposites by the combined modification of bulk and surface of nanoparticles.

Introduction

Addition of nanoparticles and their surface functionalization has been practised over the past three decades in order to enhance the ultimate properties and performance of organic coatings [1–۵]. A Nevertheless, there is a need for looking at properties of coatings containing functionalized nanoparticles from a molecular perspective so as to be able to tune properties by controlling the curability of thermoset resins under the influence of surface-functionalized nanoparticles. The difficulty is that no molecular-level gauge is available for quantifying the status quo of cross-link density of thermoset nanocomposite to assess whether or not functionalized nanoparticles added to the system are reactive towards curing moieties [6–۸]. The effect of surface modification of a wide variety of nanoparticles with low- and high-molecular weight molecules of amine, carboxylic and hydroxyl on the curability of epoxy resin was addressed in previous works of this group, which are including carbon nanotubes (CNTs) [9–۱۱], graphene oxide (GO) nanoflakes [12–۱۴], halloysite nanotubes (HNTs) [15–۱۷], silica nanoparticles [18,19] and zinc oxide (ZnO) nanoparticles [20]. Reports suggest that surface functionalization of nanoparticles with high-molecular-weight ethylenediaminetetraacetic acid (EDTA) can affect ultimate properties of cross-linkable polymer nanocomposites. For instance, Syuhada et al. showed that EDTA surface-functionalized GO was dispersed well in chitosan matrix due to interaction of EDTA functional groups with chitosan [21]. Well-dispersed GO-EDTA in chitosan matrix led to facilitation of stress transfer resulting in 71% improvement in tensile strength compared to the neat chitosan film.