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Applied Clay Mineralogy Phần 8

Thị trường montmorillonite và hectorite nanoclays sẽ tăng đáng kể trong tương lai gần vì nhiều ứng dụng mới. 6,21. Montmorillonites Organoclays Sodium với một khả năng trao đổi cao và hectorite đặc biệt được chế biến để làm organoclays. | Chapter 6 Bentonite Applications 125 for polyethylene terephthalate bottles used in the hot fill juice market. The market for montmorillonite and hectorite nanoclays will increase significantly in the near future because of many new applications. 6.21. Organoclays Sodium montmorillonites with a high exchange capacity and hectorite are specially processed to make organoclays. In this process the exchangeable ions are replaced with organic compounds such as alkylamines and many others Jordan 1949 . These organoclad montmorillonites are used as thickeners in paints greases oil-base drilling fluids to gel various organic liquids cleanup oil spills Carmody et al. 2005 and recently nanocomposites. The nano-montmorillonites are treated with organic molecules which interact with polymers to produce very strong and heat-resistant products. Raussell-Colon and Serratosa 1987 described the mechanisms of interaction and the manner in which organic reactants are arranged on the mineral substrate. The naturally hydrophilic montmorillonites can be changed so that they become organophilic or hydropholic. 6.22. Paint Montmorillonite clays are used extensively in paints. White bentonites are a preferred material if available. Those which are best are those which carry sodium as the exchangeable cation and are highly colloidal and completely dispersible. In water-based paints the sodium and or lithium montmorillonites are suspending and thickening agents. These montmorillonites are also used as an emulsifying agent in both water- and oilbased paint formulations. Organoclays can be tailor made with organic compounds to meet the requirements of different vehicles including lacquers epoxy resins and vinyl resins which are used in paint formulations. These organoclays improve pigment suspension viscosity and thixotropy control and are excellent in non-drip emulsion paint. 6.23. Paper Sodium bentonite is used in the de-inking process to recover cellulose fibers Murray 1984 . The de-inking