Surface coated iron particles via atom transfer radical polymerization for thermal-oxidatively stable high viscosity magnetorheological fluid

摘要: A surface grafting technique for poly(2-fluorostyrene) onto iron particles via atom transfer radical polymerization (ATRP) is described. Grafted poly(2-fluorostyrene)–iron were synthesized by immobilizing 2-4(-chlorosulfonylphenyl)-ethyltrichlorosilane to the through covalent bond of a silanol group, followed 2-fluorostyrene monomer. The grafted polymer–iron display higher thermal transition temperature compared bulk polymer because between backbone and restricts molecular mobility. weight has been measured it narrow distribution (Mw/Mn < 1.1). From thermogravimetric analysis, stability superior polystyrene. Also, high viscosity magnetorheological fluid (HVMRF) prepared from coated excellent thermo–oxidative stability, having nearly constant viscosity. These materials exhibit large increase in shear yield stress off- on-state as benchmark -coated particle HVMRF. In addition, this type eliminates settling which common problem found traditional fluids (MRFs). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013