Effect and Mechanism Analysis of Plasma Treatment on Electrical and Mechanical Properties of Aramid Fiber–Epoxy Resin Interface

This article presents the preparation of Kevlar aramid fiber (AF) braided fabric/epoxy resin (EP) composite laminates through plasma treatment and a hand-folding process. The electrical and mechanical properties of these composite laminates are compared and analyzed. The modified AF braided cloth is examined using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR). The results confirm an increase in the number of C=O bonds in the surface layer of the AF braided cloth, along with the generation of −COOH groups. SEM characterization reveals that plasma-modified aramid braided fabric leads to the “fibrinization” of AF, where the cortex falls off. This phenomenon promotes the physical linking between AF and EP matrix materials, thereby improving the mechanical properties of the composite material. isothermal surface potential decay (ISPD) measurements demonstrate that the modified Kevlar fiber braided cloth/EP composite exhibits higher deep trap density and improved insulation strength. Furthermore, molecular dynamics (MD) simulation is employed to analyze the impact of plasma modification on the interface characteristics of the AF/EP composites. The findings indicate that plasma treatment enhances the interaction energy density between the AF and EP, primarily on account of the formation of numerous hydrogen bonds between the surface of the modified AF and EP.