Abstract
In this study, deterioration of adhesive joint strength was investigated by lap joint specimens and butt joint specimens which
were aged under high temperature and high humidity conditions. As a result, lap shear strength of lap joint specimens decreased
with increasing aging time. From the results of surface observation and FT-IR analysis, it was confirmed that decrease of joint
strength results from deterioration of the adhesive/adherend interface and degradation of cohesion due to hydrolysis of urethane
bond. From the results of XPS measurement for butt joint specimens fractured by tensile test, it was clarified that H2O is adsorbed
at the adhesive/adherend interface after aging. It was suggested that adsorption of H2O causes decrease of hydrogen bonding force
combining adhesive/adherend interface and thus interfacial strength of the joint decreases.
