Clay conducting polymer composites

A large number of inorganic and organic substances are used as fillers in polymer composites. Calcium carbonate, barium sulfate, clays, silica, and talc are common examples. Glass beads are often used in traffic paints to increase reflectivity. Metal fibers are sometimes added to impart conductivity or to improve metal plating. A number of organic materials are also used, including wood flout cellulose, and even corncobs. We will encounter starch/ ... 

Intercalation of electroactive polymers such as polyaniline and polypyrrole in mica-type layered silicates leads to metal-insulator nanocomposites. The conductivity of these nanocomposites in the form of films is highly anisotropic, with the in-plane conductivity 10 to 10 times higher than the conductivity in the direction perpendicular to the film. Conductive polymer/oxide bronze nanocomposites have been prepared by intercalating polythiophene in V2O5 layered phase, which is analogous to clays. °° Studies of these composites are expected not only to provide a fundamental understanding of the conduction mechanism in the polymers, but also to lead to diverse electrical and optical properties. 

Another important category of conducting polymer-based composites includes films containing metal, metal oxide, clay, carbon black, semiconductor, and other types of particles (Table 20.17). These composites can be synthesized electrochemically by polymerizing the parent monomer (pyrrole, thiophene, or aniline) in a dis-... 

Natural polymer research has included use of these alternative materials with nanoparticles [487] because of three significant properties multifunctionality, biodegradabihty, and bio-compatibihty. Breakthroughs in cost of production and property profiles for biomaterials will be needed before they become reasonable to market. Research has been conducted on melt formation of a starch-clay nanocomposite for bioplastic applications [487] however, an issue is the high water uptake and thus loss in mechanical properties requiring modification of the clay and the composite process. As with other nanocomposites, microstructural characterization is typically by TEM and AFM. 

Nanocomposites are a new class of particle-filled composites in which at least one dimension of the dispersed particles is within 100 nm. Because of the dispersion of nanosize clay particles, polymer-clay nanocomposites exhibit improved moduli and strength, decreased thermal expansion coefficient, decreased gas permeability, increased swelling resistance, better thermal stability and enhanced ionic conductivity when compared to the pristine polymers or microscale composites [149-151], They find increased applications in various fields such as automobile, packaging, electronic, coating and aerospace industries [152,153],... 

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