Fabrication and Characteristics of Core-shell Structured PNMA@Fe3O4 Particles and Their Additive Effect on Magnetorheology

초록

Core-shell nanoparticles of poly(N-methyl aniline) (PNMA)/magnetite (Fe3O4 ) (PNMA@Fe3O4) were synthesized through chemical oxidation polymerization of PNMA as a core, followed by chemical co-precipitation process of magnetite coating onto the core. The morphology, chemical structure, and magnetic properties of PNMA@Fe3O4 were characterized using SEM, TEM, FT-IR, and VSM, respectively. PNMA@Fe3O4 was introduced into carbonyl iron (CI)-based magnetorheological (MR) fluid as a kind of magnetic additive to study its influence on the rheological and sedimentation properties of the MR fluid. The shear stress curves as a function of the shear rate for the MR fluids were well-fitted by the Herschel-Bulkley equation. Furthermore, the introduction of additives demonstrated an enhancement in the yield stress and solid-like properties of CI-based MR fluid under a magnetic field, while significantly reducing the sedimentation rate of the MR fluid.