Clay Nanocomposites

Dr. Kalpana S. Katti

Dr. Dinesh R. Katti

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Dr. Kalpana S. Katti

Dr. Dinesh R. Katti

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June 2005
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Fall 2002
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PRINCIPAL INVESTIGATORS

Dr. Dinesh R. Katti

Dr. Kalpana S. Katti

Department of Civil Engineering
North Dakota State University, Fargo, ND, USA

MOLECULAR INTERACTIONS IN INTERCALATED ORGANICALLY MODIFIED CLAY AND CLAY-POLYCAPROLACTAM NANOCOMPOSITES: EXPERIMENTS AND MODELING

Molecular interactions in organically modified clay and polymer clay nanocomposite are evaluated using a combination of experimental (photoacoustic FTIR, XRD) and computational (molecular dynamics (MD)) techniques. The FTIR data reveals hydrogen bond and ionic bond interaction between functional end groups of organic modifier and surface oxygen of interlayer clay sheet lying in the organically modified clay; and, the hydrogen bond formation between intercalated polymer and organic modifier and surface oxygen of clay sheet lying in the interlayer clay gallery in the polymer clay nanocomposite. The nature of interactions between clay and polymer, clay and organic modifier in polymer-clay nanocomposites are found through experiments and molecular dynamics simulations.

Katti, K.S., Sikdar, D., Katti, D.R., Ghosh, P., and Verma, D., (2006), Molecular interactions in intercalated organically modified clay and clay–polycaprolactam nanocomposites: Experiments and modeling, Polymer, v 47, 403-414.

Clay amino acid model before minimization

Interlayer Response in Compression

Interlayer Response in Tension

RESEARCH OBJECTIVE:

Development of a simulation based design of clay nanocomposites.

Small amounts of nanosized clay particles dispersed in a polymer matrix very significantly alters the mechanical and thermal properties of the composite.

Applications:

Structural composites for applications in aerospace, automobile and other engineering fields
Structural coatings
Structural biomaterials
Pharmaceutical Industry

Result of MD simulation showing organically modified clay with modifier in the sodium montmorillonite interlayer interacting with clay sheets

Photoacoustic FTIR study of clay, organically modified clay and the modifier

Mechanical Properties of Sodium Montmorillonite Interlayer Intercalated with Amino Acids

Nanosized montmorillonite clay dispersed in small amounts in polymer results in polymer nanocomposites having superior engineering properties compared to native polymer. These nanoinclusions are created by treating clay with an organic modifier which makes clay organophilic and results in intercalation or exfoliation of the montmorillonite. The modifiers used are usually long carbon chains with alkylammonium or alkylphosphonium cations. In this work, we have investigated the use of some alternative molecules which can act as modifiers for clay composites using clay for reinforcing a matrix of biopeptides or proteins. Such composites have potential applications in the field of biomedical engineering and pharmaceutical science. In this work, amino acids arginine and lysine are used as modifiers. The intercalation and mechanical behavior of the interlayer spacing with these amino acids as inclusions under compression and tension is studied using molecular dynamics simulations. Significant and unexpected differences in the responses are observed. This work also provides an insight into the orientation and interaction of amino acids in the interlayer under different stress paths.

Katti, D.R., Ghosh, P., Schmidt, S., and Katti, K.S., (2005), Mechanical Properties of Sodium Montmorillonite Interlayer Intercalated with Amino Acids, Biomacromolecules, 6, 3276 - 3282.

Coming soon : More Results