Viscoelastic and mechanical behaviors of magneto-rheological carbonyl iron/natural rubber composites with magnetic iron oxide nanoparticle

Abstract

To upgrade the magneto-rheological (MR) effect of a MR elastomer with carbonyl iron (CI) and natural rubber, needle-typed hard-magnetic gamma iron oxide (γ-Fe2O3) nanoparticles were introduced as an additive. For an anisotropic MR elastomer, an external magnetic field was employed to the samples during a fabricating process to align the CI/γ-Fe2O3 particles along a magnetic field direction. Morphology and rheological features of the CI/γ-Fe2O3 particle-based MR elastomer were compared with those of the elastomer containing pristine CI. The morphology and alignment of both MR elastomers were confirmed via high resolution scanning electron microscopy. In addition, the corresponding rheological properties were measured via a rotation rheometer under magnetic field strengths applied. Strain sweep and angular frequency sweep tests confirmed that the storage modulus increased with increased magnetic field strength. Furthermore, MR elastomer with CI/γ-Fe2O3 added had a higher modulus and exerted a stronger MR effect than the elastomer with CI only, as revealed by the intensity of both Payne and MR efficiency effects. Tensile strength and elongation percentage of the CI/γ-Fe2O3-based elastomer were better than those of pure CI-based elastomer.