Abstract
We recently found that the acrylic rubber (ACM) /epoxy adhesive via reaction-induced spinodal decomposition showed high peel strength when it was cured with diaminodiphenylmethane. Transmission electron microscopy observation revealed : (1) epoxy-rich particles are densely deposited near the surface of polyimide film (adherend), (2) by peeling, the particles are highly deformed and then fragmented via cavitation, and (3) a lot of cavities of 10-30nm diameter are generated also in ACM-rich matrix. The damaged zone by cavitation is formed in deep (800nm depth from the interface). It implies that a huge peeling energy is consumed by the massive damage and it leads to the high peel strength. By contrast, in a week adhesive cured with 1-cyanoethyl-2-phenylimidazole, the damaged zone was very thin (ca.20nm).
