Acid-base properties of carbon and graphite fiber surfaces

Wesson, Sheldon P.; Allred, Ronald E.

doi:10.1163/156856190x00306

Cited by 19 publications

(8 citation statements)

References 38 publications

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“…The present findings are consistent with results reported previously [1][2][3][4][5][6][7][8][9] that the ILSS of composite specimens is directly related to the fiber-matrix chemical and mechanical bonding for carbon fibers embedded in unmodified epoxies. Significantly, the linear improvement in ILSS from chemical bonding indicates that the mechanical contribution to the ILSS is not greatly affected by the fiber treatment.…”

Section: Discussionsupporting

confidence: 94%

“…Although covalent bonding can occasionally occur, the primary chemical bonding at the interface is shown to be hydrogen bonds formed mostly between the hydroxyl and carboxyl acid groups on the fiber surface and the epoxy groups of the adhesive. [6][7][8][9][10] Hydrogen bonding generally occurs between a proton (H) donor group (A-H) and a proton acceptor group B. The hydrogen bond (H-B) interaction can be described in terms of the Morse pair potential, 18 which we write in the form 20…”

Section: Salient Features Of the Analytical Modelmentioning

confidence: 99%

“…A number of researchers [1][2][3][5][6][7][8][9] have presented evidence that the ILSS of composite specimens is dependent on the fiber-matrix chemical and mechanical bonding for carbon fibers embedded in unmodified epoxies. Further, a comparison of ILSS measurements made on graphite-epoxy composite specimens with interfacial shear strength (IFSS) measurements made on corresponding single fiber systems 29 reveals a direct link between the values of the ILSS and the IFSS for a given carbon fiber embedded in an unmodified epoxy.…”

Section: H-bond Contibution To the Interlaminar Shear Strength Omentioning

confidence: 99%

“…The chemical bonds are mostly hydrogen bonds (H-bonds) and the bond density is greatly influenced by fiber surface treatments prior to embedding in the epoxy matrix. [6][7][8][9][10] Manufacturing errors and environmental degradation of the fiber-matrix interfaces during service of the composite can result in a reduction in strength of the adhesive bond and the ILSS. A non-destructive means of determining the chemical bond strength during manufacture and service of the composite would be useful in assessing a weakening of the ILSS and impending failure of the manufactured component.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

Cantrell

2015

AIP Advances

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The chemical treatment of carbon fibers used in carbon fiber-epoxy matrix composites greatly affects the fraction of hydrogen bonds (H-bonds) formed at the fiber-matrix interface. The H-bonds are major contributors to the fiber-matrix interfacial shear strength and play a direct role in the interlaminar shear strength (ILSS) of the composite. The H-bond contributions τ to the ILSS and magnitudes KN of the fiber-matrix interfacial stiffness moduli of seven carbon fiber-epoxy matrix composites, subjected to different fiber surface treatments, are calculated from the Morse potential for the interactions of hydroxyl and carboxyl acid groups formed on the carbon fiber surfaces with epoxy receptors. The τ calculations range from 7.7 MPa to 18.4 MPa in magnitude, depending on fiber treatment. The KN calculations fall in the range (2.01 – 4.67) ×1017 N m−3. The average ratio KN/|τ| is calculated to be (2.59 ± 0.043) × 1010 m−1 for the seven composites, suggesting a nearly linear connection between ILSS and H-bonding at the fiber-matrix interfaces. The linear connection indicates that τ may be assessable nondestructively from measurements of KN via a technique such as angle beam ultrasonic spectroscopy.

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Section: Discussionsupporting

confidence: 94%

Section: Salient Features Of the Analytical Modelmentioning

confidence: 99%

Section: H-bond Contibution To the Interlaminar Shear Strength Omentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

Cantrell

2015

AIP Advances

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“…In part, the issue depends on the force field exerted on the probe molecule by the solid. As pointed out in recent publications, 10,[21][22][23] almost all solid surfaces are heterogeneous and possess finite site-energy distributions. Thus, it may be expected that the probe molecules may adopt a range of configurations depending on the energies of sites with which they interact.…”

Section: Introductionmentioning

confidence: 90%

Probe selection and description in IGC: A nontrivial factor

Schreiber¹

2003

J of Applied Polymer Sci

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Inverse gas chromatography (IGC) has found many uses in the characterization of polymer surfaces and their interaction capabilities. The IGC method relies on the selection of vapors with which to probe polymer surfaces. Problems attached to the volatile phase in IGC are considered. One of these is the temperature dependence of the probe molecule dimensions. Experimental work shows that correcting for this temperature dependence is recommended when IGC work is carried out at temperatures removed from the ambient by more than 30°C. A second problem area is a possible variation in the orientation of adsorbed probe molecules. The variable orientation of linear alkane probe molecules on a polystyrene substrate is demonstrated, as is an orientational degree of freedom when diols of varying chain lengths are adsorbed on polymeric as well as on inorganic substrates. A conclusion reached from the experiments of this work is that acid-base parameters generated by the IGC method have relative but not necessarily absolute significance. Further, the orientation of polar probe molecules is dependent on the force field generated by the underlying substrate, which may be characterized by its total surface free energy.

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The relation between carbon‐fibre surface treatment and the fibre surface microstructure

Mahy

Jenneskens

Grabandt

et al. 1994

Surface & Interface Analysis

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The effect of an electrochemical surface treatment on the surface microstructure of Tenax@ high-tensile-strength carbon fibres is investigated using a multi-technique approach. The fibres are treated in a laboratory set-up, which simulates the production conditions. The surface functional groups are characterized and quantified, and their dependence on the treatment intensity is determined. The surface chemistry is correlated with the fibre surface topography. It is observed that for increasing treatment intensity, the surface area does not increase significantly (except at very high intensities, in which a porous structure is formed). This contrasts with the dispersive part of the surface energy, which increases with the treatment intensity. Moreover, both basic and acidic surface functionalities are formed, the relative proportions of which change with the treatment intensity.These phenomena can be interpreted in terms of the concentration of active sites, which increases with the surface treatment and may be related to 'basal plane edges' of the (disordered) graphitic fibre microstructure.

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Acid-base properties of carbon and graphite fiber surfaces

Cited by 19 publications

References 38 publications

Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

Probe selection and description in IGC: A nontrivial factor

The relation between carbon‐fibre surface treatment and the fibre surface microstructure

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