Self-assembling Magnetic Microspheres by P(St-co-AA) and Fe₃O₄ Nanoparticles

Uniform P(St-co-AA) microspheres were prepared by microemulsion polymerization.The Fe_3O_4/P(St-co-AA) mierospheres with a high magnetic content were prepared by electrostatic self- assembly using P(St-co-AA) microspheres with Fe_3O_4 nanoparticles synthesized by co-precipitation. The effects of pH,stirring on the preparation of Fe_3O_4/P (St-co-AA) were investigated.All samples were characterized by transmission electron microscope (TEM),scanning electron microscope(SEM), X-ray diffraction(XRD),FTIR spectroscope.The magnetic property of the obtained magnetic powder with Fe_3O_4 single phase was tested by VSM.The results indicate that the average sizes of polymer microspheres P(St-co-AA) with carboxyl and the magnetic powders Fe_3O_4 are 70nm and 10nm,re- spectively.Magnetic property measurement shows that the saturated magnetization of the magnetic powders is 69A.m~2·kg~(-1) when the applied field is up to 1.5×10~6/π(A/m) at room temperature.The assembled Fe_3O_4/P(St-co-AA) with an average size of 800nm is spherical and the content of magnetic powders is 15.8%.