Investigation of the quantitative relationship between IR spectra and stress–strain curves of cured adhesives immersed in water

Abstract

Cured adhesives subjected to a water or heat environment undergo changes in their chemical structure, resulting in a deterioration in their mechanical properties over time. Infrared (IR) spectroscopy can be applied to reveal the changes in the chemical structure of cured adhesives. However, there is a lack of research on the quantitative relationship between the IR spectra and mechanical properties (such as the parameters associated with the stress–strain curves). In this study, to clarify the quantitative relationship between the IR spectra and mechanical properties of structural adhesives, tensile tests were performed on cured adhesives immersed in water. The results of the analysis obtained using an estimation model showed linear relationships between the parameters associated with the stress–strain curve, including the tensile strength, and the IR spectra. These relationships made it possible to estimate the changes in the stress–strain curves of the cured adhesives immersed in water over time from the IR spectra.