Maruti Bentoclay Pvt Ltd Bhuj, Gujarat

BENTONITE is the important naturally occurring clay of great commercial importance possessing inherent bleaching properties. It is, therefore commonly called bleaching clay. It fall mainly under montmorillonite group containing a varying amount of attapulgite. The montmorillonite is designated by the chemical formula (OH4).Si8.O20.nH2O. The clay minerals of montmorillonite and attapulgite groups are distinguished by their adsoption characteristics.

The clay mineral Attapulgite derives its non-swelling needle-like morphology from its three-dimensional crystal structure. The shape and size of the needles result in unique colloidal properties, especially resistance to high concentrations of electrolytes, and give high surface area, high porosity particles when thermally activated. Examples of industrial applications of attapulgite are reviewed with emphasis on how these characteristic properties function in the various end-uses.

Liquid crystallinity in polymers may occur either by dissolving a polymer in a solvent (lyotropic liquid-crystal polymers) or by heating a polymer above its glass or melting transition point (thermotropic liquid-crystal polymers). Liquid-crystal polymers are present in meltedliquid or solid form. In solid form the main example of lyotropic LCPs is the commercial aramid known as Kevlar. Chemical structure of this aramid consists of linearly substituted aromatic rings linked by amide groups.