Electrode Potential Regulation of Carbon Fiber Based on Galvanic Coupling and Its Application in Electrochemical Grafting.

Abstract

The reaction behavior of carbon fiber in electrochemical grafting is related to its electrode potential. In this paper, carbon fiber and metals with different electrode potentials were used to form combined electrodes to regulate the electrode potential of carbon fiber. The results showed that galvanic coupling was formed in the combined anode when the potential difference between carbon fiber and the metal (Δϕ = ϕCF0 - ϕmetal) was higher than 0.05 V. The electrode potential of carbon fiber was reduced due to cathodic polarization. The electrode potential of carbon fiber after galvanic coupling was proportional to the self-corrosion potential of metals. By applying the electrode potential regulation of carbon fiber in the electrochemical grafting of poly(glycidyl methacrylate) onto the carbon fiber surface, the grafting effect was significantly improved with the decrease of the electrode potential of carbon fibers. The grafting amount of carbon fibers increased from 0.83 to 69.86% as the electrode potential of carbon fibers dropped from 0.55 to -0.72 V. Consequently, the interfacial shear strength of the carbon fiber composite was remarkably promoted from 47.59 to 81.41 MPa, increasing by 71.07%.