Addition of Cloisite 30B nanoclay particles to a typical ammonium dichromate cured liquid polysulfide elastomeric adhesive leads to very dramatic increase in the aluminum-aluminum joint strength measured by 180 degrees peel test. The increase in adhesive strength could be explained in terms of higher cohesive strength of the nanocomposite adhesives, which has been derived from good interaction between the nanoclay and the polysulfide elastomer. The addition of nanoclay also facilitates the adhesive to dissipate greater amount of energy (by fibrils formation) during the debonding process of the peel test. In addition, the nanoclay aids the low polarity polysulfide elastomer to achieve better molecular contact with the aluminum substrate. The nanoclay particles are very well dispersed (mostly exfoliated) in the polymer matrix even at 8 wt% of nanoclay concentration. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies provide evidences for the excellent dispersion of the nanoclay platelets in the polymer matrix. The results of the mechanical and dynamic mechanical studies confirm the excellent interaction between the nanoclay and the polysulfide elastomer. (C) Koninklijke Brill NV, Leiden, 2009