Entirely aqueous synthesis of polyimide silsesquioxane nanocomposites

A novel combination of a modified Stober sol-gel technique to prepare silsesquioxane nanoparticles with an aqueous synthesis of polyimide resin has been used to prepare polyimide-silsesquioxane nanocomposites. The products have been analysed to ascertain the degree and mode of association between the polyimide matrix and silsesquioxane nanoreinforcement. Thermal analysis techniques have been used to quantify the attraction between the resin and four different surface-functionalised silsesquioxanes. Scanning electron microscopy has been used to assess qualitatively the nature of the interaction between the two components. In general, aminopropyl-functionalised silsesquioxanes have the lowest level of interaction with the polyimides used in this study, while methyl- and phenyl-functionalised nanoparticles bind more strongly with the resin. Silica nanoparticles have a relatively strong association with the polyimide and appear to be largely attached to the surface of the polymer. (c) 2006 Society of Chemical Industry.