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In situ Production of Polystyrene Magnetic Nanocomposites through a Batch Suspension Polymerization Process
Author(s) -
Neves Juliete S.,
de Souza Fernando G.,
Suarez Paulo A. Z.,
Umpierre Alexandre P.,
Machado Fabricio
Publication year - 2011
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201100050
Subject(s) - materials science , polystyrene , superparamagnetism , nanocomposite , suspension polymerization , coprecipitation , chemical engineering , magnetic nanoparticles , nanoparticle , polymerization , emulsion polymerization , styrene , composite material , polymer , nanotechnology , magnetization , copolymer , magnetic field , physics , quantum mechanics , engineering
This work presents the synthesis of micro‐sized polystyrene magnetic beads by in situ incorporation of oleic acid‐modified Fe 3 O 4 magnetic nanoparticles via a suspension polymerization process. Fe 3 O 4 nanoparticles with superparamagnetic characteristics were obtained through a coprecipitation technique. These particles present an average diameter equal to 7.4 ± 4.6 nm, as determined by AFM. This result is in agreement with the crystallite size of single domains calculated by using Scherrer's equation, which was equal to 7.7 nm, based on XRD measurements. The obtained materials were also studied using TGA. The weight loss behavior was independent of the Fe 3 O 4 content and the stability to the thermal degradation was also not improved by magnetic nanoparticles present in the composite. Polystyrene/Fe 3 O 4 magnetic nanocomposites exhibited the same diffraction peaks observed in the pure Fe 3 O 4 , which indicates that nanoparticles inside the composites preserved the structure and properties of pure Fe 3 O 4 . It was also shown that nanosized polystyrene particles, dispersed in the aqueous phase, are obtained due to the stabilization effect of the oleic acid on the styrene droplets. A cross‐section of polystyrene magnetic particles showed empty spherical regions, attributed to the encapsulation of water microdroplets during the polymerization reaction. The obtained polymeric materials also presented good magnetic behavior, indicating that the modified Fe 3 O 4 nanoparticles were successfully dispersed in the polystyrene particles.