Analytical and experimental investigation on magnetorheological behavior of CoFe2O4-rGO-incorporated epoxy fluid composites

CoFe2O4-reduced graphene oxide (CoFe2O4-rGO) composites were synthesized by one-pot solvothermal technique. Different amount of well-dispersed nanosized cubical grains of CoFe2O4-rGO were incorporated into the epoxy resin for the preparation of fluid composite samples. The magnetorheological properties of the prepared samples showed significant enhancement in yield strength as well as viscoelastic properties. The flow curves of the samples showed non-Newtonian behavior at lower strain rate (gamma <10 s(-1)) under high magnetic field strength, thereafter with increasing the value of <gamma>, the flow curves shifted Newtonian regime. The composite samples also possessed a yield stress (tau (y)) under a magnetic field at adequately high strain rates and followed Bingham relation tau=tau y+gamma <mml:mo>'</mml:mover>eta 0, where, tau is shear stress perpendicular to the applied magnetic field and eta (0) is the plastic viscosity. The experimentally obtained values of tau (y) for different values of B-0 and correspond well to the values predicted theoretically by Rosensweig.Magnetorheological properties of CoFe2O4-rGO/epoxy epoxy composite prepared by mechanical mixing are superior to that of neat epoxy.