Monodisperse carboxylated superparamagnetic polymer composite microspheres with high magnetite content were prepared by miniemulsion copolymerzation

in which acrylic acid and styrene were used as polymeric monomers

and Fe3O4 microparticles were costabilized by undecylenic acid /oleic acid.Extensive characterizations by transmission electron microscopy (TEM)

Zeta-sizer

thermogravimetric analysis (TGA)

fourier transform infrared spectrometer (FTIR) and physical property meaturement system (PPMS) showed that the surface modification of Fe3O4 microparticles played an important role in controlling the magnetite content and the morphology of the composite microspheres.Under optimized experimental conditions

the superparamagnetic polymer composite microspheres with diameter of 137.9 nm

high magnetite content (77 wt%) and 0.0894 mmol carboxyl groups/g microspheres were successfully produced.