Layer silicate clays 2:1:1 type

Clay minerals are characterized by a high surface charge and a very small particle size. A detailed presentation of two types of layered silicate clay (kaoUnite and smectite) is given in Chapter 1. 

Noncrystalline aluminosilicates (allophanes), oxides, and hydroxides of Fe, Al, and Mn, and even the edges of layer silicate clays to a lesser extent, provide surface sites for the chemisorption of transition and heavy metals. All of these minerals present a similar type of adsorptive site to the soil solution a valence-unsatisfied OH or H2O ligand bound to a metal ion (usually Fe ", AF, or Mn ). For example, on iron oxides, a trace metal, M, may bind according to the reaction... 

Clays are strongly hydrophilic in nature, making their dispersion in organic matrices difficult [26]. There are usually three possible arrangements of these layered silicate clays, which can be obtained when they are dispersed in a polymer matrix. If the polymer cannot intercalate between the silicate sheets, a non-intercalated microcomposite is obtained. Beyond this traditional class of polymer-filler composites, two other types of composites can be obtained. An intercalated structure is one in which the separation of clay layers occurs to some extent by increasing the interlayer spacing. 

In this work, the starch/PVOH/silicate clay blend films were prepared by a solution casting method. Four different types of layered silicate clays were used to investigate the compatibility of multiphased system. Special attention is driven to study the effect of the clay content on the film properties based on barrier and mechanical modeling predictions of nanocomposite films. 

The ineorporation of a few weight pereent of modified layered silieates whieh are properly dispersed in the mbber matrix ean result in very high surface areas for rubber-elay interactions, as compared to the conventional rubber-filler composites. According to the strength of the interfacial interactions between rubber matrix and layered silicate four type of rubber-clay composites can be produced ... 

Three main types of composites can be formed when the layered clay is incorporated with a polymer, as shown in Figure 2 (Alexandre and Dubois, 2000). Types of composites formed mostly depend on the nature of the components used (layered silicate, organic cation and polymer matrix) and the method of preparation. 

Weiss A (1963) Mica-type layer silicates with alkylammonium ions. Clays Clay Miner 10 191-224... 

Clays are layer silicates (phyllosilicates) of particle size less than about 4 pm, produced by the weathering of aluminosilicate rocks. Clay minerals fall roughly into two structural classes the kaolinite type, based on paired sheets of tetrahedral (SiC>44-) and octahedral [A10n(0H) g " or... 

On the other hand, Bhattacharya et al. have reported the plasticization effect of organically modified layered silicates on dynamic mechanical properties [13]. In this work, nanocomposites of SBR have been prepared using various nanofillers like modified and unmodified montmorillonite, SP, hectorite etc. It has been observed that the Tg shifts to lower temperature in all the nanocomposites, except for systems from hectorite and NA. This is due to the fact that clay layers form capillaries parallel to each other as they become oriented in a particular direction. Due to wall slippage of the unattached polymer through these capillaries, the Tg is lowered, which could be even more in the absence of organo-modifiers [13]. A similar type of plasticization effect is also noted in the case of the low... 

---