Polymer Nanocomposites in Emulsion and Suspension

Mittal V. Chapter 1 polymer nanocomposites in emulsion and suspension an oyerview. In Mittal V, editor. Polymer nanocomposites by emulsion and suspension polymerization. Cambridge, UK The Royal Society of Chemistry 2011. p. 1-31. 

Chapter 1 provides a brief overview on the synthesis of polymer nanocomposites in emulsion and suspension. Other synthetic methodologies such as in situ polymerization and melt intercalation are also described in comparison with emulsion and suspension polymerization. Chapter 2 describes the use of layered double hydroxides for the synthesis of nanocomposites in both emulsion and suspension. Properties and potential applications of such composites are considered. Chapter 3 describes nanocomposite synthesis in the inverse... 

P. Ding and B. J. Qu, Synthesis and characterization of polystyrene/layered doublehydroxide nanocomposites via in situ emulsion and suspension polymerization. Journal of Applied Polymer Science, 101 (2006), 3758-66. 

One of the techniques frequently used to prepare a polymer-clay nanocomposite is emulsion or suspension polymerization. This is similar to in situ polymerization in that the clay is exfoliated prior to polymerization, but it is exfoliated in a solvent (or aqueous phase) rather than in a monomer. In some cases the surfactant used for the polymerization process also becomes part of the final nanocomposite, either yielding an organoclay as part of the polymerization process or serving as a compatibilizer between organoclay and polymer. " Emulsion or suspension processes are being used increasingly as a tool for breaking the clay particles apart before polymerization. Part of the reason for the increase in the use of this technique is that bulk polymerization does not always lend itself to industrial scale-up, whereas emulsion and suspension polymerizations may be more suitable for this purpose. Ultimately, the choice between those methods depends on the polymer system in question. 

In conclusion, emulsion and suspension polymerization methods have become promising methods for preparing polymer-LDH nanocomposites based on the above advantages. In the past 5 years, various polymer-LDH nanocomposites... 

From the above discussion, it can be seen that the method adopted to prepare nanocomposites is highly dependent on the nature of the polymer. When the polymers or monomers are water soluble, they can be incorporated into the pristine LDH without any organo-modification due to their good affinity with the LDH. Additionally, the aqueous environment is compatible with the condition for the synthesis of LDH materials. Therefore, water-soluble polymer-LDH nanocomposites can be prepared using some special methods such as in situ synthesis, ion exchange and reconstruction. In the case of water-insoluble polymers and monomers, their nanocomposites are usually prepared in orga-nosolvent (solution intercalation method, exfoliation-absorption method and in situ polymerization method) or molten polymer (melt intercalation method). However, emulsion polymerization and suspension polymerization are methods that allow the incorporation of a water insoluble polymer into an LDH in water. The following sections are devoted to polymer-LDH nanocomposites obtained via emulsion polymerization and suspension polymerization. 

Compared with emulsion polymerization and suspension polymerization, the manufacturing process of suspension polymerization of inverse emulsion is more complicated. The advantage of using this technology is to make a capsular structure which has a polymer shell and liquid inner phase. The polymer shell can provide protection by preventing the inner phase from leaking out. When nanoparticles are added to the polymer shell, they can inhibit mass transfer and reinforce the polymer matrix to make the nanocomposites stronger or thermally stable. More importantly, the presence of nanoparticles can partially replace or completely eliminate the use of emulsifiers in the nanocomposite bead synthesis process. One application, as mentioned before, is to make PS nanocomposite... 

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