Trilayer Composite Poly(styrene/butyl acrylate/acrylic acid) Terpolymer Microspheres with Fe2O3 Middle Layer: Synthesis and Characterization

Abstract

Fe2O3 particles with diameter of 3–5 nm were encapsulated in polymer spheres (styrene/butyl acrylate/acrylic acid terpolymer latex) by emulsion polymerization. Control of the pH value of the medium and modification of the latex prior to the second polymerization were of importance in determining the microstructure and morphology of the composite particles. The interaction between Fe2O3 and seed latex was confirmed by IR spectral changes of the surface groups of the latex particles. Mossbauer spectra gave evidence for the changes of electric density and electric field symmetry around Fe2O3, and surface photovoltage spectra indicated that the Fe2O3 particles were encapsulated in polymer. It was shown by all the results that the composite microspheres of size 80 nm had a core–shell structure with trilayers of seed latex core, Fe2O3 nanoparticles middle layer and polymer shell. © 1997 SCI.