(309e) Strengthened Magnetic Epoxy Nanocomposites with Protruding Nanoparticles on the Graphene Nanosheets

Magnetic   graphene (Gr) nanocomposites (Gr nanosheets coated with iron core iron oxide shell nanoparticles, named Gr/Fe@Fe₂O₃) have successfully served as nanofillers for obtaining magnetic epoxy resin polymer nanocomposites (PNCs) to be compared with the epoxy nanocomposites with pure graphene. Due to the high stiffness of Gr and the stress releasing function of the protruding Fe@Fe₂O₃ nanoparticles, the PNCs displayed improved mechanical properties and the highest tensile strength was observed in the PNCs with 1.0 wt% Gr/Fe@Fe₂O₃, which is 58% higher than that of the pure epoxy. In addition, the Gr/Fe@Fe₂O₃ was found to favor the char formation from the epoxy resin, and the morphology study of char residue indicated that Fe@Fe₂O₃ could assist the porous char layer formation in the PNCs with Gr/Fe@Fe₂O₃ which led to reduced flammability. The magnetic properties of the PNCs were also studied and due to the decreased interparticle dipolar interaction, the value of coercivity (Hc) was observed inversely proportional to the loading of Gr/Fe@Fe₂O₃ in the PNCs. A reduced viscosity was observed in the 1.0 wt% Gr–epoxy resin liquid nanosuspensions and the viscosity was increased with further increasing the Gr loading. The dynamic storage and loss modulii were studied together with the glass transition temperature (T_g) obtained from the peak of tand. The effects of nanofiller loading levels on electrical conductivity and dielectric property were systematically studied. Both nanofillers could increase the electrical conductivity of the epoxy matrix. And the increased real permittivity observed in the PNCs is attributed to the interfacial polarization.