PMMA coated carbonyl iron microbeads and their magnetic characteristics

In order to improve the stability of magnetorheological (MR) fluid, we synthesized poly(methyl methacrylate) (PMMA) - encapsulated carbonyl iron (CI) particles by an in-situ dispersion polymerization method. In addition, PMMA shell was cross-linked by a cross-linking agent. The cross-linked PMMA is expected to be more effective than non-cross-linked PMMA, improving the physical properties. The synthesized CIPMMA composite particles were characterized by SEM, and VSM. Cross-linking of PMMA was also confirmed by measuring the FT-IR after etching process. Rheological properties of the PMMA-coated CI based MR fluid were measured via a rotational rheometer. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.