Dynamic mechanical analysis of magnetorheological composites containing silica-coated carbonyl iron powder

This article describes the dynamic mechanical analysis of the behaviour of magnetorheological composites consisting of a magnetically active filler (carbonyl iron powder) and a soft thermoplastic elastomer matrix (styrene-ethylene-butylene-styrene). The carbonyl iron particle surface was coated by a sol–gel silica layer to improve the adhesion between hydrophilic magnetic particles and the hydrophobic polymer. Isotropic magnetorheological composites containing 81.25 wt% unmodified and silica-coated carbonyl iron powder were manufactured. The surface morphology of the carbonyl iron particles was observed using transmission electron microscopy, while its magnetic properties were analysed with a vibrating sample magnetometer. The magnetomechanical properties of the prepared magnetorheological composites were determined through shearing tests performed in various magnetic fields. The magnetorheological composites containing modified carbonyl iron powder have lower magnetorheological effect in comparison to the composites with pure carbonyl iron powder.