Hydrated alumina-silicate-layered

The MMT, a hydrated alumina-silicate layered clay consisting of an edge-shared octahedral sheet of aluminum hydroxide between two silica tetrahedral layers (Fignre 2) with dimensions, 1 nm thick and 100-500 nm in diameter, result in platelets of high... 

Aspect ratios (length/thickness) greater than a thousand are possible [29]. MMT is the most commonly used layered silicate. It is a hydrated alumina-silicate layered clay mineral consisting of an edge-shared octahedral sheet of aluminum hydroxide between two silica tetrahedral layers [6,30]. Highly favorable polymer-surface interactions are essential for thorough clay sheet dispersion [31,32]. Thus, it is conventional to organo-modify these clays with cationic surfactants in order to improve compatibility with the polymer matrix and to faciUtate delamination and exfoliation [3]. 

Illite [(K,H30)(AlMg,Fe) (Si,Al)p ((0H), (Hp))] is a non-expanding micaceous mineral. It occurs as aggregates of small monoclinic grey to white crystals. It is layered alumina-silicate consisting of poorly hydrated potassium Cation, which is responsible for the poor swelling behavior. Its structure consists of repetition of tetrahedron- octahedron - tetrahedron (TOT) layers. The cation exchange capacity (CEC) of illite is comparatively better than kaolinite (20-30 meq/100 g). 

II. The dissolution rate is controlled by interdiffusion of hydrogen or hydronium ions and species contained in lattice sites within the interior of the silicate phase. This process results in a leached layer consisting mainly of silica and alumina. Such a layer may retain the original silicate structure (W, 11) or may represent a collapsed or hydrated layer (12, 13). 

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