Effect of certain hostile environments on adhesive joints

Abstract

Abstract The effects of water vapour on aluminium‐aluminium bonded joints, using a Bisphenol A diglycidyl ether epoxide resin cured with bis‐(4‐aminophenyl)‐methane as the adhesive, have been studied. A distinction has been drawn between the effect on joint strength and on polymer strength. The very significant fall in joint strength compared with the change in polymer strength is used to postulate that in adhesive joints of this type, water molecules rapidly enter the boundary region to interfere with the secondary valence forces responsible for adhesion between substrate and organic adhesive. The results are further interpreted as support for the view that the polymer adjacent to the metal substrate is likely to differ in structure and conformation from the main polymer mass, namely a boundary layer. Similar experiments using the less polar ethanol provide further evidence for the hypotheses.