Achieving broadband microwave absorption and excellent mechanical properties via constructing 3D reduced graphene oxide networks in glass fiber/epoxy resin composites

The rapid development of electronic information technology makes it more urgent that explore high-efficiency microwave absorption materials to cope with the challenges of electromagnetic pollution for guarding information security and human health. Herein, we prepared functional composites with both broadband microwave absorption and excellent mechanical properties via constructing three-dimensional (3D) reduced graphene oxide (RGO) networks. In these composites, glass fibers (GFs) were uniformly coated by RGO through a straightforwardly feasible repeated dip-coating process and subsequent reduction, which were named (RGO)n@GF (n was dip-coating times). The GFs supported RGO to form 3D networks, which increased the transmission paths and multiple scattering of electromagnetic waves. Meanwhile, the networks improved the electrical conductivity and conduction loss. The results show that the (RGO)10@GF reinforced epoxy resin (EP) composites ((RGO)10@GF/EP) have particularly significant improvement in microwave absorption properties, achieving a broad effective absorption bandwidth of 7.54 GHz and a low reflection loss of −46.02 dB. Compared with GF/EP, the bending strength and modulus of (RGO)10@GF/EP increased by 39% and 45%, respectively. The present work provides an effective solution for developing advanced composites with both broadband absorption and excellent mechanical properties.