Polydimethylsitoxane/HTiNbO5 nanocomposites were prepared through four different routes: melt intercalation of the pure mineral, melt intercalation of the organically modified mineral, grafting by a sol-gel process, and grafting by anionic ring-opening polymerization. The four nanocomposites were characterized using wide-angle X-ray scattering and rheometry, at different solid fractions. No exfoliated structure was observed, for any system prepared, but in situ polymerization techniques, especially the ionic polymerization process, were shown to lead to the more structured nanocomposites. This study mainly shows that PDMS master batch made of in situ synthesized systems is probably a well-suited route to achieve high performance silicon elastomer nanocomposites. (c) 2005 Elsevier Ltd. All rights reserved.