(188al) The Surface Coated Iron Particles Via Atom Transfer Radical Polymerization (ATRP) for Novel Thermal–Oxidative Stable High Viscosity Magnetorheological Fluid (HVMRF)

The surface grafting technique of poly(fluorostyrene) onto iron particles via atom transfer radical polymerization (ATRP) has been used for intelligent materials, namely magnetorheological fluids (MRFs), resulting in a novel thermo?oxidative stable high viscosity magnetorheological fluid (HVMRF). The grafted poly(fluorostyrene)?iron particles were synthesized by immobilizing 2-4(-chlorosulfonylphenyl)-ethytrichlorosilane to the iron particles through the covalent bond of a silanol group, followed by the polymerization of 4-fluorostyrene monomer. A novel HVMRF was prepared from surface coated iron particles and has excellent thermo?oxidative stability in terms of viscosity consistency and the change of shear yield stress for off- and on-state compared to benchmark HVMRF and non-surface coated iron particles HVMRF. In addition, the properties of surface grafted poly(fluorostyrene)?iron particles were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy?X-ray energy dispersive spectrum, and differential scanning calorimetry. The grafted poly(fluorostyrene)?iron particles showed a higher thermal transition temperature compared to bulk polymer because the covalent bond between the polymer backbone and the surface of the iron particles restrict the molecule mobility.