Desalination 199 (2006) 164–166 Presented at EUROMEMBRANE 2006, 24–28 September 2006, Giardini Naxos, Italy. 0011-9164/06/$– See front matter © 2006 Elsevier B.V. All rights reserved. Nanocomposite-based polyamide 12/montmorillonite: relationships between structures and transport properties Benjamin Alexandre a *, Stéphane Marais a , Dominique Langevin a , Pascal Médéric b , Thierry Aubry b a Laboratoire PBM, UMR 6522/CNRS, 76821 Mont-Saint-Aignan Cedex France email: benjamin.alexandre@etu.univ-rouen.fr b Laboratoire de Rhéologie, Université de Bretagne Occidentale, 6 Av. Le Gorgeu, C.S. 93837, 29238 Brest Cedex 3, France Received 26 October 2005; accepted 2 March 2006 Abstract Water transport through nanocomposite-based polyamide 12/montmorillonite was investigated by permeation kinetics. Intercalated and semi-exfoliated nanocomposite structures were studied. For low montmorillonite content (£ 5%) a decrease of water permeability was obtained for a both structures and mainly explained by an increase of the tortuosity (decrease of water diffusivity). However, this barrier effect is affected by other phenomena which depend on the structures: the plasticization phenomenon, the water solubility and the role played by the clay/polymer interface. Keywords: Water permeation; Sorption; Nanocomposites; Polyamide 12, Montmorillonite; Plasticization 1. Introduction Polymer/layered silicate nanocomposites have become an important class of polymeric compos- ites since they exhibit dramatic enhancement in barrier, thermal and mechanical properties [1–3] even at very low silicate contents. It is well- known that these properties are strongly affected by the affinity between the matrix and the clay, the degree of clay exfoliation, the dispersion and the orientation of clay particles throughout the thermoplastic matrix. The chemical strategy used to modify the surface of the clay and the melt processing conditions are a key player in achieving structure and properties of the final product [4]. In this work, the effects of the structure of the nanocomposite (volume fractions, intercalated and semi-exfoliated structures) on water transport are investigated by perme- ation kinetics, electron microscopy and X-ray diffraction. *Corresponding author. doi:10.1016/j.desal.2006.03.035