Nanocomposites were prepared using montmorillonite with different organic modifiers (cloisite 10 A, cloisite 15 A, and cloisite 20 A) and the effect of intercalant structure on clay morphology and chlorobutyl vulcanization kinetics was investigated. Because of its lower rigid structure the aliphatic salt was easier to intercalate into the clay galleries giving rise to a higher interlayer distance and facilitating the rubber intercalation obtaining an exfoliated structure in the nanocomposite. The vulcanization process was sensibly accelerated by this organoclay and a higher crosslinking degree was observed in the nanocomposite which gave rise to materials with improved processing and physical characteristics. The present work focuses on characterising the surfaces of organically modified MMT clays and the relationship to the final properties of their nanocomposites. Concentrating on the surface modifiers, one has to take into account their interaction with the matrix polymer, the solubility of the organic molecule adding to the complexity due to its influence. We aim to show that understanding the influence of surface characteristics is the basis for selecting the ideal organoclay for the given matrix polymer. Depending on the nature of the surfactant used for the organic modification of clay and its modifier concentration the nanocomposites exhibit difference in the properties. The organoclays used in the present study were selected to explore the effects of the amine surfactant structure on the dispersion of clay particles in chlorobutyl rubber matrix. The structure of the organic amine compound used to form the organoclay is expected to have some effect on the morphology and properties of the nanocomposites. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011