Kinetics of Nanocomposite Formation

Kinetics is another important factor in determining if a mixture of nanoparticles and polymer can form a nanocomposite. The extent of nanoparticle dispersion (e.g., exfoliation of the stacks of clay platelets, debonding of nanotube bundles, and deagglomeration of nanosphere agglomerates) in a polymer matrix is affected critically by the kinetic barriers. Such kinetic barriers often inhibit the formation of thermodynamically favorable structure. 

The kinetics of nanocomposite formation is much less understood. In clay-polymer mixtures, it is still unclear how the surfactant or polymer get into clay gallery and form the intercalated or exfoliated stmcture since the gallery is initially separated by less than 1 nm and thus hinders the infusion of external species. Thus, some important issues must be addressed (i) How do the galleries open for the accommodation of intercalating surfactant or polymer (ii) By what mechanisms do the chains enter the galleries (iii) What factors may affect the penetration of polymers into the galleries (iv) How does the diffiisivity of the intercalated chains compare to that of bulk chains Some theoretical efforts have recently been made toward such kinetics issues of nanocomposite formation. 

Coarse-grained MD simulations have been employed to study the kinetics of polymer flow into the slit - a process similar to the intercalation of polymer into clay gallery. It is showed that a moderate clay-polymer afftnity is needed to achieve the spontaneous intercalation of polymer and swelling of day [6j. A relatively higher 

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A current wide set of experimental data concerns mainly the yield characteristics of systems such as nanoparticle distribution in the size and matrix space, physical and chemical properties of the matrix formed, and so on. At the same time, the investigations on the mechanism and kinetics of nanocomposite formation and on understanding how these parameters change during thermal transformations are absent because of the difficulties of the experimental studies of the kinetics of such processes. 

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