Electrochemical Bonding of Amines to Carbon Fiber Surfaces Toward Improved Carbon‐Epoxy Composites

Abstract

Electrochemical oxidation of o~-diamines on carbon fibers allows the bonding of these molecules to the carbon fibers. The conditions leading to this surface modification are described, and the influence of the different parameters is discussed. The structure of the bonded layer is studied by voltammetry, XPS, and SIMS. A mechanism is proposed which involves the coupling of a radical cation to the fiber. Toughness of carbon-epoxy composites is improved when prepared from these modified fibers.ABSTRACT Electrochemistry was used on-line with high-performance liquid chromatography with mass spectrometric and UV-vis spectrophotometric detection to characterize the electrochemical oxidation pathways of 6-thiopurine and 6-thioxanthine. At low potentials, the electrochemical oxidation of 6-thiopurine proceeds via one electron resulting in disulfide formation. It is proposed that purine-6-sulfenic acid is formed at potentials > +0.50V. Further oxidation of this unstable

Electrochemical Synthesis of Three-Dimensional Polyaniline Network on 3-Aminobenzenesulfonic Acid Functionalized Glassy Carbon Electrode and Its Application

“…It can be seen from Figure 2 that, the maximal peak at 400.2 eV is assigned to the characteristic peak of N(1s) environment, which is also consistent with the formation of C-N bond between the amine cation radical and the aromatic moiety of GCE surface [26,27]; and the peak at 163.3 eV shows the presence of S(2p). This verifies the attachment of ABSA on GCE surface.…”

“…that there is a broad, irreversible anodic peak at 1.28 V in the first cycle, and no cathodic peak is observed on the reverse scan, this indicates that the species obtained after the first electron transfer undergoes a chemical reaction. During this process, the amino group in ABSA was first oxidized electrochemically to turn into its corresponding cation radical via a one-electron oxidation; then, these cation radicals form C-N covalent bonds at carbon electrode surface [26,27]. In the next 4 scans, the oxidation peak shows a negative shift from cycle to cycle with a quickly decreased current response.…”

Chemically Modified Carbon Nanotubes: Derivatization and Their Applications

“…Two strategies have been reported in the literature, one is the reductive strategy which involves the electrochemical reduction of aromatic diazonium salts and the other includes the oxidation of aromatic amines [10] which have been discussed elaborately in reviews appeared recently [9,11]. The reductive strategy was initially developed by Jean Pinson and co-workers in 1990 [12] and later developed by a number of workers including McCreery [13] and Downard group [9]. The basic mechanism involved in this modification is the generation of aryl radical at the solution/electrode interface by one electron electroreduction of corresponding diazonium salt and its subsequent attachment on the surface of carbon nanotubes which results in the formation of covalent bond between carbon atom of substrate and carbon atom of the modifier molecule.…”

“…The basic mechanism involved in this modification is the generation of aryl radical at the solution/electrode interface by one electron electroreduction of corresponding diazonium salt and its subsequent attachment on the surface of carbon nanotubes which results in the formation of covalent bond between carbon atom of substrate and carbon atom of the modifier molecule. The schematic modification of the carbon surface has been shown in the figure 1 [12]. Fig.…”

Covalent modification of glassy carbon spheres through ball milling under solvent free conditions: A novel electrochemical interface for mercury(II) quantification

“…Chemical modification imports new set of properties to the carbon substrates which were not available in its unmodified counterparts [2]. Several strategies have been reported for their modification, which includes electrochemically assisted covalent modification with aromatic primary amines through an oxidative strategy and with diazonium salts through a reductive strategy [3,4]. This method results in the formation of well organized layers on the carbon substrate which can be used as modified electrodes.…”