Montmorillonite platelets

FIG. 10 Pressure curves for Na+-mica surfaces in a 2 mol/L NaCl solution calculated from Eq. (27) and converted for flat surfaces. Also represented is the swelling pressure for a Na-montmorillonite platelet system. Inset pressure curves measured using the direct force method [51]. 

Voorn and coworkers demonstrated the inverse Pickering miniemulsion polymerization of aqueous acrylamide and 2-hydroxyethyl methacrylate in cyclohexane using hydrophobically modified Montmorillonite platelets (cloisite 20A) as solids stabilizer [110]. 

Voorn DJ, Ming W, Van Herk AM (2006) Polymer-clay nanocomposite latex particles by inverse Pickering emulsion polymerization stabilized with hydrophobic montmorillonite platelets. Macromolecules 39(6) 2137-2143... 

Osman, M. A., Ploetze, M., and Skrabal, P. J. 2004. Structure and properties of alkylammonium monolayers self-assembled on montmorillonite platelets. Journal of Physical Chemistry B 108 2580-2588. 

Montmorillonite platelets corrld corrtribute to the negative birefringence in PVDF systems because the refractive index value norrrtal to the basal plane is smaller than the... 

Montmorillonite platelets are particularly effective for reducing thermal expansion coefficients of plastics, as shown in Figure 4.2 for used exfoliated polyamide 6 nanocomposites. 

As an example, Tsugita et al. [22] showed that liquid paraffin emulsions can be stabilized by using Na-montmorillonite and polar organic substances (glycerol monopal-mitate). A network structure is formed by the interaction of the Na-montmorillonite platelets and stabilizes the emulsion. A general paper is presented in Ref. 23. 

Proceeding from the description of intercalated nanocomposites adduced in Section 7.1, it can be supposed that the polymeric material between Na -montmorillonite platelets is interfacial regions. In this case the interfacial layer thickness /. is determined as follows [23] ... 

The results of computer simulation of a system consisting of two Na -montmorillonite platelets and a crosslinked epoxy polymer between them is presented in Figure 7.9. Attention is paid to the fact that the molecule at the surface has a denser and flatter packing in comparison with the initial free conformation of this macromolecule. This means that such macromolecules near the silicate platelet surface form interfacial regions, which are structurally different from the bulk polymer matrix. Knowing the simulated platelet thickness of Na -montmorillonite (9.7 A), the value of /. can be estimated according to the data of Figure 7.9 as equal to 6.7 A. 

Figure 7.9 The structure of a QM optimised cluster, consisting of two interacting Na+-montmorillonite platelets, grafted by (CH (CH2)j7)NH3 and a crosslinked epoxy polymer model macromolecule. Atoms and bonds are represented as balls and rods. View from the side [22]...

Figure 1.17 Structures of the organic modifiers 1-3 used to ion exchange on the surface of montmorillonite platelets. Reproduced from reference 82 with permission from the American Chemical Society.

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