Superparamagnetic magnetite–divinylbenzene–maleic anhydride copolymer nanocomposites obtained by dispersion polymerization

• Published in: European polymer journal Vol. 48; no. 10; pp. 1709 - 1716
• Main Authors: Donescu, Dan, Raditoiu, Valentin, Spataru, Catalin Ilie, Somoghi, Raluca, Ghiurea, Marius, Radovici, Constantin, Fierascu, Radu Claudiu, Schinteie, Gabriel, Leca, Aurel, Kuncser, Victor
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2012; Elsevier
• Subjects: Anhydrides; Anisotropy; Applied sciences; Composites; Constants; Copolymers; Dispersion polymerization; Dispersions; Divinylbenzene–Maleic Anhydride copolymer; Exact sciences and technology; Forms of application and semi-finished materials; Magnetite; Nanocomposite; Nanoparticles; Polymer industry, paints, wood; Polymerization; Superparamagnetic; Technology of polymers; Nanocomposite; Superparamagnetic; Magnetite; Divinylbenzene–Maleic Anhydride copolymer; Dispersion polymerization; Benzene(divinyl) copolymer; Iron oxide; Diffuse reflection; Superparamagnetism; Experimental study; Composite particles; Particle size distribution; Magnetic particles; Reflection spectrum; Divinylbenzene-Maleic Anhydride copolymer; Optical properties; Morphology; Preparation; Alternating copolymer; Alternating copolymerization; Maleic anhydride copolymer; Microparticle; Radical copolymerization; Magnetic properties
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2012.07.012

[Display omitted] ► Composites containing magnetite were obtained by dispersion polymerization. ► The hybrids show good dispersion of inorganic nanofillers in the polymeric matrix. ► Thermal stability of the matrix in the presence of magnetic filler was enhanced. ► Magnetite nanoparticles have an average size of about 23nm in copolymer particles. ► A superparamagnetic behavior was evidenced for the obtained nanoparticles. Magnetite alternating copolymers divinylbenzene–maleic anhydride (DVB–MA) composites were prepared by dispersion polymerization. Because magnetite is used as a complex with oleic acid (Fe3O4OLA), the final hybrids show good dispersion of inorganic nanofillers in the polymer matrix. The obtained composites were analyzed by infrared absorption spectrometry, diffuse reflectance in visible light, thermogravimetry, X-ray fluorescence, X-ray diffraction, dynamic light scattering, scanning electron microscopy and vibrating sample magnetometry. The obtained results indicate the successful preparation of magnetite nanoparticles with an average size of about 23nm dispersed in micrometer size copolymer spherical particles, which relative content can be controlled via the processing parameters. A relationship between the relative content of magnetite nanoparticles and the size of the polymer particles, with direct influence on the diffuse reflectance in the visible domain, was observed. A superparamagnetic behavior was evidenced at room temperature with a blocking temperature lower than as expected from the bulk anisotropy constant and the average size of the magnetite nanoparticles. Both the unexpected low blocking temperature and the observed low specific magnetizations were explained by a defected and poor crystalline structure of the magnetite nanoparticles, giving rise to spin disorder and diminished crystalline anisotropy constant.