Synthesis of poly(p-phenylenediamine) encapsulated graphene and its application in steel protection

Graphene (G) is an excellent protection material, but suffering corrosion-promotion effect because of its intrinsic high electrical-conductivity. Herein, a facile strategy is presented to effectively lower the conductivity of the G by the encapsulation of insulating poly(p-phenylenediamine) (PpPD). The obtained G@PpPD, which delivers an extremely low conductivity of 3.5×10 −7 S cm -1 , were then mixed with polyvinyl-butyral (PVB), forming a compact composite coating that can effectively protect Q235 steel from being corroded over a very long period. Such a superior anticorrosion property can be owing to the synergistic effect between impermeable graphene and insulated PpPD, which not only hinders the diffusion of the corrosive media, but also inhibits the corrosion-promotion activity of the graphene. This effective strategy may provide valuable enlightenment for the further development of graphene-based polymer anticorrosive coatings with long-lasting corrosion resistance .