Mechanism of weak bond formation in CFRP epoxy adhesion joints

Abstract

Saltwater contamination, such as human factored sweat dew and breath moisture, is studied to explain the mechanisms of weak bond formation in carbon fiber reinforced plastics (CFRP) epoxy adhesive joints. First, a mechanism of epoxy ring consumption by $C{l}^{-}$ is proposed to explain the reduction of covalent bond density at the adhesion interphase in a function form of pH alkaline drift. Second, a double cantilever beam test (DCB test) is applied to saltwater-polluted CFRP adhesion samples to prove the formation of the contamination-triggered weak bonds. Applying the data to the function, the thickness of the contamination layer is estimated to imply that adhesive flow in the adhesion process dissipates the layer to make the weak bond formation a statistical phenomenon.

Keywords:

• CFRP
• DCB test
• epoxy adhesive
• saltwater contamination
• weak bond

Acknowledgements

This study is based on Japanese article of Journal of the Japan Society for Composite Materials, Volume 46, No.4, 2020. This work was supported by Innovative Science and Technology Initiative for Security, ATLA Japan. We would like to thank Editage (www.editage.jp) for English language editing.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Innovative Science and Technology Initiative for Security, ATLA Japan. Please access URLhttps://www.mod.go.jp/e/publ/w_paper/pdf/2016/DOJ2016_3-3-1_web.pdf and see Chapter 3 “Active Utilization of Civilian Technology.”