Polymer/organoclay nanocomposites

Ruiz-Hitzky E, Van Meerbeek A (2006) Clay mineral- and organoclay-polymer nanocomposite. In Bergaya F, Theng BKG, Lagaly G (eds) Handbook of clay science. Development in clay science. Elsevier, Amsterdam, pp 583-621... 

E. Ruiz-Hitzky and A. Van Meerbeek, Clay mineral and organoclay-polymer nanocomposites. In Handbook of Clay Science, ed. F. Bergaya, B. K. G. Theng, and G. Lagal (Amsterdam Elsevier, 2006), pp. 583-621. 

Traditionally, organoclay-polymer nanocomposites were synthesized by either the solution intercalation method or in-situ intercalative polymerization. However, it was the possibility of direct melt intercalation by... 

The most commonly studied polymer nanocomposites are clay-based nanocomposites, mainly with montmorillonite (MMt) as layered silicate filler (Scheme 15.12). Upon incorporation of organomodihed clays (organoclays) into a polymer matrix, two nanomorphologies (Scheme 15.13) can be obtained, either intercalation of the polymer chain in between the clay platelets keeping the stacking of the sheets, or exfoliation of the clay platelets with a disordered dispersion of the inorganic sheets in the polymer. 

Fig. 13.12 Polymer nanocomposites containing spherical silica nanoparticles in vinyl ester (left) and exfoliated organoclay...

The pol5mier nanocomposite field has been studied heavily in the past decade. However, polymier nanocomposite technology has been around for quite some time in the form of latex paints, carbon-black filled tires, and other pol5mier systems filled with nanoscale particles. However, the nanoscale interface nature of these materials was not truly understood and elucidated until recently [2 7]. Today, there are excellent works that cover the entire field of polymer nanocomposite research, including applications, with a wide range of nanofillers such as layered silicates (clays), carbon nanotubes/nanofibers, colloidal oxides, double-layered hydroxides, quantum dots, nanocrystalline metals, and so on. The majority of the research conducted to date has been with organically treated, layered silicates or organoclays. 

The impact strength of clay-polymer nanocomposites either increases, decreases or remains unaltered by the nano-clay incorporation. The impact strength is not altered much by the presence of nano-clay, as reported elsewhere [21]. A special co-intercalation type of organoclay was used. In another study, an improvement in impact property is noticed while incorporating nano-clay in PP matrix [58]. The Izod impact strength of PP and CPN is shovm in Figure 9.37. 

Hotta, S. and Paul, D. R. 2004. Nanocomposites formed from linear low density polyethylene and organoclays. Polymer 45 7639-7654. 

Betega de Paiva et al. (2008) analyzed properties, synthesis, and applications of organoclays (especially bentonite and polymer nanocomposites), modifications with several chemical compounds as quaternary alkylammonium salts and also biomolecules as enzymes that provide applicability in a variety of fields. 

Several methods have been used to obtain polymer nanocomposites by using organoclays [29-32], i.e. solution intercalation [33-39], melt intercalation [40, 41], and in situ interlayer intercalation [30, 42, 43], Among them, in situ interlayer polymerization relies on swelling of... 

The main uses of montmorillonite stem from its characteristic expansion, and it is used to control viscosity or impart thixotropy to a variety of liquid polymers based on unsaturated polyesters, PVC plastisols, polysulfides, alkyds, etc. It has also been reported to control the melt rheology of thermoplastics and to reinforce polyamides. There has, over the last few years, been enormous industrial and research interest, with many papers and patents, published on montmorillonite, especially as an organoclay as the basis of polymer nanocomposites. Because of the delamination process described above plastic-organoclay nanocomposites have been reported to have very high rigidity, low permeability to fluids, and fire resistance. This subject is covered in more detail in Chapter 10. 

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