Miniemulsion fabricated Fe3 O4 /poly (methyl methacrylate) composite particles and their magnetorheological characteristics

초록

In order to improve drawbacks such as sedimentation of magnetic particles and abrasion of the magnetorheological (MR) fluid, we have fabricated Fe 3 O4 /poly(methyl methacrylate) (PMMA) composite particles via a double miniemulsion method and studied their MR properties. Morphology and chemical composition of the synthesized Fe3 O4 /PMMA composite particles were investigated by transmission electron microscopy and Fourier transform infrared, respectively. The density of the Fe3 O4 /PMMA composite particles was measured to be lower than that of the as-synthesized Fe3 O4 particles, indicative of an improvement of the composite particles to stay dispersed. Rheological characteristics of the Fe3 O4 /PMMA based MR fluid dispersed in a nonmagnetic carrier fluid were measured by both static and dynamic tests using a rotational rheometer under an external magnetic field. Shear stress, yield stress, and storage modulus from the rheological measurements were obtained to be increased with applied magnetic field strengths. © 2010 American Institute of Physics.