Intercalated Clays-Precursors for Polymer Nanocomposites
Josef Simonik, Lucie Kovarova, Pavla Capkova, Zdenek Weiss
Tomas Bata University in Zlin,Faculty of Technology
Czech Republic

Keywords: Nanocomposites, Polymer, Clay

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Clay minerals intecalated with organic species (long aliphatic chains, oligomers, polymers) are of great technological interset becose of their applications as procursors of polymer-clay nanocomposites. Intercalation of clay minerals can be achieved by two different ways:(a)Ion-exchange reaction(exchange of interlayer cations by organoammonium cations) and (b) Adsorption of polar organic molecules into the interlayer space,based on ion-dopole interacition of guest species with interlayer cations and host layers.

In present work we investigate the structure of montmorillonite intercalated with cetytrimethylammonium and cetylpyridinium cations and motmorilonite intercalated with neutral molecules of octadecylamine using molecular mechanics and molecular dynamics simulations combined with X-ray powder diffraction. Molecular simulations were carried out in a Cerius modeling enviroment.

Results of the structure analysis showed that cetylpyridium and cetyltrimethyammonium cations are disordered in the interlayer space with the polar head-groups adjacent to the host layers. On the other hand the octadecylamine exhibits certain degree of order in the interlayer space in depence on the guest concentration. For the low guest concentrations of octadecylamine we get the disordered interlayer structure. With higher concentration the monolayer arrangement of guests exhibits the smectic structure and with increasing concentrations the arrangements of guests becomes gradually bilayer. In addition to the detailed structure model including the characteristics of disorder, we obtained the charge distribution and energy characteristics such as total sublimation energy, partial host-guest and guest-guest interaction energies, exfoliation energy and Van der Waals and Coulomb components.