Polymeric nanobead coated carbonyl iron particles and their magnetic property

Magnetic carbonyl iron (CI) particles have attracted great attention due to their high saturation magnetization and appropriate particle size for magnetorheological (MR) materials. However, hydrodynamic instability of the CI particle suspension which was attributed to the large density mismatch between the dispersed CI particles and the medium has affected its predominant role for MR applications. A novel magnetic CI/polystyrene (PS) composite with nano‐scaled PS spheres sprinkled on the surface of the CI particles was fabricated via a normal dispersion polymerization in this work. Physical properties, MR behaviors as well as the improvement in sedimentation problem were investigated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)