Magnetic nanocomposites based on hydrogenated epoxy resin

A hydrogenated derivative of diglycidylether of bisphenol A (HDGEBA) has been successfully employed to prepare magnetic thermosetting nanocomposites. Magnetite nanoparticles of ≈10 nm modified with oleic acid were synthesized by co-precipitation of ferric and ferrous salts in ammonium solutions. Nanocomposites with amounts up to 5% w w−1 of nanoparticles were dispersed in HDGEBA by co-solvent method and cured with m-xylilendiamine. Both the particles and nanocomposites were characterized by FTIR, DSC, TGA, XRD, TEM, DMTA and VSM. Due to the lower polarity of the hydrogenated resin, the enhanced compatibility with magnetite oleic coverage allowed obtaining good dispersions of the nanoparticles for compositions up 1% w w−1, while at higher concentration agglomerates were observed. Two behaviors in the thermal properties were obtained: for compositions below 1% w w−1 the glass transition temperature increased with the amount of nanoparticles, whereas for higher amounts the glass transition temperature decreased. Superparamagnetic behavior was observed in both the particles and the nanocomposites; the blockage temperature gradually increases with loading but it is lower than the observed for bulk magnetite nanoparticles. This fact reflects that nanoparticle–nanoparticle distances in the nanocomposites gradually decrease with loading which is in accordance with a good dispersion state for low loadings and the presence of aggregates at high loadings.