Mechanism of Weak Bond Formation in CFRP Adhesive Joints

This work aims to explain the mechanisms of weak bond formation in CFRP epoxy adhesive joints by studying aqueous NaCl mist contamination. First, a mechanism of epoxy ring consumption by Cl－ ion was proposed to explain the reduction in covalent bond density at the adhesion interphase, as a function...

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Bibliographic Details
Published inJournal of the Japan Society for Composite Materials Vol. 46; no. 4; pp. 121 - 129
Main Authors MORIMOTO, Tetsuya, FUJIMOTO, Akihiro, KATOH, Hisaya, KUMAZAWA, Hisashi
Format Journal Article
LanguageEnglish
Japanese
Published The Japan Society for Composite Materials 15.07.2020
Subjects
CFRP
DCB test
Epoxy adhesive
Saltwater pollution
Weak bond
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Summary:This work aims to explain the mechanisms of weak bond formation in CFRP epoxy adhesive joints by studying aqueous NaCl mist contamination. First, a mechanism of epoxy ring consumption by Cl－ ion was proposed to explain the reduction in covalent bond density at the adhesion interphase, as a function of pH alkaline drift. Second, double cantilever beam test (DCB test) was applied to CFRP joint samples with aqueous NaCl mist contamination at the adhesion interphase to prove a weak bond triggered by Cl－ ion contamination. Third, contamination layer thickness was estimated by substituting the data into the drift function. Obtained nanometer-thin thickness indicates that the stirring flow of the adhesive dissipates the layer to form a standard joint, while steady flow keeps the layer to form a weak-bond joint. Therefore, 1) Cl－ ion contamination at the adhesion interphase and 2) the handling in the adhesion process explain the statistical aspect of weak bond formation in the production line of CFRP adhesive joints.
ISSN:0385-2563
1884-8559
DOI:10.6089/jscm.46.121