Preparation And Interfacial Property Of Graphene Oxide/BPEI/Carbon Fiber Hierarchical Reinforcement

In order to meet the development needs of production, daily life and national defense fields, we need to optimize and control the performance of the advanced composite materials. The thickness and structure of the composite’s interphase phase have a huge impact on the performance of the composite material, so it is necessary to design and control the interface of composite material. Carbon fiber composite is of vital importance in the field of materials, but as the reinforcement, it can not achieve good adhesion with the polymer matrix because of its relatively smooth inert graphite layer and the lower surface energy, it lead to poor infiltration performance. In order to increase the amount of active functional groups on carbon fiber surface, and improve the reaction activity of functional groups and the polymer matrix, the researchers grafted molecules which have a large number of active amino groups onto the carbon fiber surface through amide action. But the peptide coupling reagents in amide action are strongly toxic, and the reaction process is relatively complex, so this paper use a more environmentally friendly, convenient and quick way to modify carbon fibers’ surface, prepared and study the mechanism of the corresponding changes in interfacial properties of branched polyethylenimine grafted carbon fiber hierarchical reinforcement and graphite oxide graphene grafted carbon fiber hierarchical reinforcement.The main research contents of this paper are as follows:Prepared branched polyethylenimine grafted carbon fiber hierarchical reinforcement through electrostatic interaction; verified the branched polyethyleneimine and carbon fiber connected by chemical bond by XPS; the surface energy test suggested that the introduction of branched polyethyleneimine made the carbon fiber hierarchical reinforcement’s surface energy increased 90%and improved the adhesive properties of carbon fiber and polymer matrix; the results of XPS analysis, trend of changes in the surface energy and micro droplet bonding results showed that when branched polyethyleneimine solution concentration is0.1% wt, made the largest contribution on the interface strength, the interfacial shear strength enhanced 46.34% compared to raw carbon fiber.With branched polyethyleneimine as the medium, the graphene oxide was grafted onto the surface of carbon fiber, the mechanical interlock of carbon fiber reinforcement and polymer matrix was strengthened, and it improved the surface energy of carbon fiber, and then improved the interface strength of the composite.The surface chemical state of carbon fiber reinforcement characterized by XPS confirmed that the branched polyethyleneimine was a medium which graftedgraphene oxide onto surface of carbon fiber by chemical bond; identified the optimal reaction concentration, reaction time and reaction method of graft reaction by SEM; the surface energy test suggested that the introduction of graphene oxide improve the wettability of carbon fiber with polymer matrix by 47.08%; interface shear strength test showed that after grafting graphene oxide, the interface strength of carbon fiber and matrix increased by 18.44%.