Surface Coating of Aramid Fiber by a Graphene/Aramid Nanofiber Hybrid Material to Enhance Interfacial Adhesion with Rubber Matrix

A novel method of constructing nanostructures on the surface of aramid fiber (AF) was demonstrated in this article. Through the π–π* interaction between the aramid nanofiber (ANF) and graphene (G), the G/ANF dispersion stably existed in water. In an alkaline solution of tannic acid (TA) and polyethyleneimine (PEI), a TA/PEI (TP) layer was deposited on the surface of AF to introduce functional groups. Then, the modified AF was impregnated with the G/ANF dispersion to construct surface nanostructures to enhance the interfacial adhesion between the fiber and rubber. The results showed that the H pull-out force of the AF and rubber after impregnating with G, ANF, and G/ANF was increased by 15.3, 21.5, and 84.7%, respectively, compared with the untreated AF. The Raman spectroscopy and SEM results show that there is a π–π* interaction between G and ANF, and the ANFs are firmly attached to the surface of G. The hybrid G/ANF nanofiller can form 3D nanostructures on the surface of AF to improve the mechanical interlocking and stress transfer between the fiber and the rubber matrix, thereby achieving excellent interfacial adhesion while maintaining the excellent mechanical properties of AF.