Within the fascinating world of nanomaterials in general, polymer-clay nanocomposites more than carry their weight in terms of intrigue and applicability. Consider all the factors that must be involved in the dramatic modification and improvement of a polymer’s behavior upon the addition of just a few weight percent (wt%) of a nano-size inorganic sheet compound. Tensile modulus and strength can be doubled and the heat distortion temperature dramatically increased (by 100˚C), without any sacrifice in impact resistance, upon the addition of just 2% by volume of this compound to nylon, for

example. These inorganic, layered silicate species are clays, and the wealth of chemistry involved in the polymer-sheet silicate interaction shall comprise the contents of this chapter.