Magnetorheological Elastomers

A new class of materials termed MR elastomers (MRE) has been developed which responds to externally imposed magnetic fields. Magnetic particles are embedded in viscoelastic solids or liquid elastomeric precursors. This kind of composite demonstrates a unique combination of good magnetic controllability and elastic properties. A significant change in the structure of several MRE matrices was observed using AFM images. Modifications of conventional elastomers includes plasticizing the polymer matrices and particle-modified systems such as silane organic coatings and nanostructured polymer grafting techniques. In addition, a solvent vaporization technique was used for surface polymerization of iron particles with isobutyl trimethoxysilane as a coating agent. The thermal and mechanical behavior was evaluated with differential scanning calorimetry (DSC) and a mechanical testing device (Instron). The effects of plasticizer, particle coating modifications, and iron particle alignment were imaged and analyzed using scanning electron microscope (SEM) equipped with an electron probe microanalyzer energy dispersive X-ray spectrometer (EDS). Images of the particles/shells were taken to confirm the existence of the coating, and analysis was used to determine oxidative stability of the particle systems after a one month submersion in a simulated sea water environment.