Influence of particle coating on dynamic mechanical behaviors of magnetorheological elastomers

In this paper, core-shell structured poly methyl methacrylate (PMMA) coated carbonyl iron (CI) particles were prepared to study the influence of particle coating on the dynamic properties of magnetorheological elastomers (MREs). The CI-PMMA composite particles were encapsulated via an emulsion polymerization method. Two MRE samples were prepared with CI-PMMA composite particles and CI particles, respectively. Their microstructure was observed by using a scanning electron microscope (SEM). Dynamic properties of these two samples under various strain and magnetic fields were measured with a dynamic mechanical analyzer (DMA). The experimental results indicate that the MRE sample with CI-PMMA composite particles has larger storage modulus, smaller loss factor and smaller Payne effect than that of the sample with only CI particles. The analysis indicates that the use of CI-PMMA particles would increase the bond strength between particles and matrix. These experimental results were also verified by the SEM images.