Cyanate ester resin filled with graphene nanosheets and CoFe2O4 reduced graphene oxide nanohybrids as a microwave absorber

Novel composites composed of CoFe2O4 spheres and reduced graphene oxide (RGO) were synthesized by using a facile hydrothermal route in combination with calcination at 550 degrees C. A series of characterization results indicate that the as-prepared CoFe2O4 spheres with relatively uniform sizes are homogeneously distributed on RGO layers. As absorbing materials, absorption properties of the graphene sheets (GNSs)/RGO-CoFe2O4 nanohybrid/cyanate ester resin (CE) composites were investigated in the measured microwave range of X-band (8.2-12.4 GHz). It can be found that the maximum reflection loss of the GNSs/RGO-CoFe2O4 nanohybrid/CE composites can reach -21.8 dB at 11.8 GHz with a thickness of 1.25 mm, and the frequency bandwidth less than -10 dB is from 9.6 to 12.4 GHz. The enhanced electromagnetic absorption property of the composites was attributed to the better impedance matching. While, when the GNSs loading is 5 wt%, high permittivity of the composites is harmful to the impedance match and results in strong reflection and weak absorption. Therefore, the GNSs/RGO-CoFe2O4 nanohybrid/CE composites, with excellent electromagnetic absorption properties and wide absorption bandwidth, can be obtained via adjusting the filler content to meet wide applications in the aerospace industry. (C) 2015 Elsevier B.V. All rights reserved.