Advertisement

Polymer Layered Silicate Nanocomposites

Authors

  • Prof. Emmanuel P. Giannelis

    Corresponding author
    1. Department of Materials Science & Engineering Cornell University, Ithaca, 6NY 14853-1501 (USA)
    • Department of Materials Science & Engineering Cornell University, Ithaca, NY 14853-1501 (USA)
    Search for more papers by this author
    • Emmanuel Giannelis studied chemsitry at the University of Athens, Greece, being awarded his B.S. in 1980. He then moved to Michigan State University, USA, and was awarded a Ph.D. in 1985. After a spell as a Research Associate at Michigan State, with Profs. Thomas Pinnavaia and Cris Berglund he moved to Cornell University as an Assistant Professor in 1987. Currently he is an Associate Professor in the Department of Materials Science and Engineering at Cornell, where his research interests include materials chemistry, polymer-ceramic nanocomposites, intercalation, thin ceramic films, and mesoscopic (nanocrystalline) materials.


  • This work was sponsored by the National Science Foundation through the Materials Center at Cornell, AFOSR, WPAFB and by generous gifts from Corning Inc., Southern Clay Corp. Xerox and DuPont. I would like to thank my co-workers Shelly Burnside, Phil Messersmith and Rich Vaia who made this work possible. I would also like to thank Larry Scanlon and Wlodek Krawiec for collaborating on the polyelectrolytes project. Finally, this review was initiated during a sabbatic sponsored by the MRL at UC-Santa Barbara. Special thanks to Tony Cheetham and Galen Stucky for their hospitality.

Abstract

Polymer nanocomposites with layered silicates as the inorganic phase (reinforcement) are discussed. The materials design and synthesis rely on the ability of layered silicates to intercalate in the galleries between their layers a wide range of monomers and polymers. Special emphasis is placed on a new, versatile and environmentally benign synthesis approach by polymer melt intercalation. In contrast to in-situ polymerization and solution intercalation, melt intercalation involves mixing the layered silicate with the polymer and heating the mixture above the softening point of the polymer. Compatibility with various polymers is accomplished by derivatizing the silicates with alkyl ammonium cations via an ion exchange reaction. By fine-tuning the surface characteristics nanodispersion (i. e. intercalation or delamination) can be accomplished. The resulting polymer layered silicate (PLS) nanocomposites exhibit properties dramatically different from their more conventional counterparts. For example, PLS nanocomposites can attain a particular degree of stiffness, strength and barrier properties with far less inorganic content than comparable glass- or mineral reinforced polymers and, therefore, they are far lighter in weight. In addition, PLS nanocomposites exhibit significant increase in thermal stability as well as self-extinguishing characteristics. The combination of improved properties, convenient processing and low cost has already led to a few commercial applications with more currently under development.

Ancillary