Epoxy resin/graphene nanoplatelets composites applied to galvanized steel with outstanding microwave absorber performance

Abstract The necessity of new electromagnetic interference shielding materials has expanded scientific research, especially with regard to microwave frequency range (X-band). In this context, polymer-based composites with nanoparticles – such as graphene – are promising electromagnetic interference shielding materials. In this work, epoxy resin/graphene nanoplatelets (NPG) composites with 0.10, 0.25 and 0.5% w/w were developed and applied to galvanized steel substrates. Dynamic-mechanical tests showed that the addition of NGPs increased the resin rigidity due to molecular restrictions of the organic chains imposed by the NPG. With the increase of the NPG concentration to 0.50%, the impact strength and the adhesion of the composites significantly decreased due to the formation and propagation of large cracks, followed by delamination. The epoxy resin sample containing 0.25% NPG presented the best microwave absorber performance with an increase of 48% in the attenuated energy and 80% in the reflection loss, respectively. Moreover, this sample extended the microwave absorption range to 10 GHz.