Dielectric Response of Adhesive Joints to Water Absorption

Nairn, B. J.; Dickstein, P. A.; Plausinis, D.; Spelt, J.K.

doi:10.1080/00218469508028158

Cited by 16 publications

(7 citation statements)

References 12 publications

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“…A similar study of aluminium adhesively bonded joints using three dierent commercial epoxy resin systems has been published [20]. Using embedded electrodes it was observed that, for an average water content of less than 2 per cent, a linear relationship exists between the permittivity and the total water content.…”

Section: Study Of Ageing In Adhesively Bonded Structuresmentioning

confidence: 85%

Non-destructive examination of adhesively bonded structures using dielectric techniques: Review and some results

Affrossman

Banks

Hayward

et al. 2000

Proceedings of the Institution of Mechanical Engineers, Part C:

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The use of high-frequency dielectric measurements is described for the non-destructive evaluation of adhesively bonded structures. Frequency domain measurements have been used to monitor the ingress of moisture into the joint structure. A good correlation has been observed between the data obtained from gravimetric and dielectric measurements. On prolonged exposure to water, changes occur to the surface oxide in the case of aluminium/aluminium joints to produce a surface hydroxide. The conversion process of oxide to hydroxide has a distinct dielectric signature. A correlation is observed between the changes in the failure mechanism and the variation in the dielectric pro®le. Time domain data have been used to investigate the integrity of the pristine bonded structure and the changes that occur on ageing. Examples of the application of the technique to both the aluminium and to carbon ®bre/carbon ®bre bonded structures are presented. The sensitivity of the technique to the occurrence of defects is critically discussed. A method for the study of bonds using a non-contacting method is outlined.

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Section: Study Of Ageing In Adhesively Bonded Structuresmentioning

confidence: 85%

Non-destructive examination of adhesively bonded structures using dielectric techniques: Review and some results

Affrossman

Banks

Hayward

et al. 2000

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…The effect of absorbed moisture on the molecular interactions and relaxation dynamics in polymer networks is an interesting, fundamentally important and incompletely understood problem. − The work presented herein addresses this issue by examining a glassy thermoset network exposed to moisture with the combined use of broadband dielectric relaxation spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), and molecular simulations.…”

Section: Introductionmentioning

confidence: 99%

Local Dynamics and Molecular Origin of Polymer Network−Water Interactions as Studied by Broadband Dielectric Relaxation Spectroscopy, FTIR, and Molecular Simulations

Mijović¹,

Zhang²

2003

Macromolecules

118

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An investigation was carried out of the molecular interactions and local relaxation dynamics in glassy polymer networks exposed to moisture. Stoichiometric and off-stoichiometric mixtures of the diglycidyl ether of bisphenol A (DGEBA) and diethylene triamine (DETA) were prepared, cured, and investigated. The physical and the chemical nature of the interactions between the network and the absorbed moisture were studied by broadband dielectric relaxation spectroscopy (DRS), Fourier transform near-infrared (FT-NIR) spectroscopy, and molecular simulations. Dry networks are characterized by two Arrhenius-like local relaxations: the β process, associated with hydroxyl groups, and the γ process, associated with primary and secondary amine, and glycidyl ether groups. Absorbed water interacts with the network and affects the dynamics of β and γ processes. FT-NIR spectra reveal the presence of three forms of water molecules, differing in the number of hydrogen atoms (0, 1, or 2) that participate in hydrogen bonds. The relative ratio of each form to the total absorbed water was calculated from the NIR data and from molecular simulations. An excellent agreement between those two techniques was observed.

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“…Kwon et al [14] demonstrated that it is possible to monitor the cure of an adhesive using dielectrometry with steel adherends as the two electrodes. Nairn et al [15] showed that it was possible to obtain the dielectric response of an adhesive between two aluminum adherends and determine the moisture level in the adhesive. This could be done using Downloaded by [University of Cincinnati Libraries] at 05:47 03 January 2015 the adherends as electrodes or by embedding an electrode in the center of the adhesive.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical impedance spectroscopy inspection of composite adhesive joints

Davis¹,

Mani²,

Rich³

et al. 2005

Journal of Adhesion Science and Technology

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Lap shear joints comprised of aluminum-aluminum, aluminum-glass fiber-reinforced polymer (GFRP), aluminum-carbon fiber-reinforced polymer (CFRP), CFRP-CFRP, CFRP-GFRP and GFRP-GFRP, were exposed to 95% relative humidity (RH) at 50 • C, 70 • C and 90 • C, to salt fog and to a 90 • C/95%RH freeze cycle. Electrochemical impedance spectroscopy (EIS) spectra were taken across the whole bonded assembly using an EIS corrosion sensor. Periodically, some specimens were pulled to obtain bond strength as a function of exposure. As expected, the higher the temperature, the faster the bond degradation. The low-frequency impedance correlated with bond strength of the humidity-exposed specimens and showed the same Arrhenius dependence, suggesting that moisture absorption by the adhesive was the limiting factor in bond performance and that EIS has the potential to nondestructively track bond health and warn of deterioration.

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Dielectric Response of Adhesive Joints to Water Absorption

Cited by 16 publications

References 12 publications

Non-destructive examination of adhesively bonded structures using dielectric techniques: Review and some results

Non-destructive examination of adhesively bonded structures using dielectric techniques: Review and some results

Local Dynamics and Molecular Origin of Polymer Network−Water Interactions as Studied by Broadband Dielectric Relaxation Spectroscopy, FTIR, and Molecular Simulations

Electrochemical impedance spectroscopy inspection of composite adhesive joints

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