Nanolayered Clay

Nanolayers of clay interacting with polymers to form nanocomposites with improved material properties relative to the untreated polymer are discussed in Chapter 17. 

Solvent blending Solvent blending, also called solution intercalation in the case of clay and other nanolayers, involves both dispersing the nanoadditive and dissolving the matrix polymer in a solvent or a solvent mixture. Three parameters have been considered to be important, particularly for clays, in choosing the surface treatment of the nanoadditives with this process The structure of the modifier, its miscibility with the polymer, and its thermal stability. The miscibility of the modifier here has two meanings miscibility with both the final polymer and the solvent chosen to dissolve the polymer. The modifier structure and its miscibility are perhaps more important than the thermal... 

In the case of PNs containing nanoadditives other than nanolayers, such as CNTs and POSS, the terms above are not used. They also show similar observations as those seen for the clay in the polymer matrix Aggregated to a large extent (immiscible or partially immiscible) or a few nanoadditive nanoparticles or separated into single nanoparticle, and all of these may coexist in the same PN. 

Examples of the use of nanostructured materials for packaging applications have been given in Chaudhry et al. (2008) and references therein. One of the first market entries into the food packaging arena was polymer composites containing clay nanoparticles (montmorillonite). The natural nanolayer structure of the clay particles impart improved barrier properties to the clay-polymer composite material. Some of the polymers which have been used in these composites for production of packaging bottles and films include polyamides, polyethylene vinyl acetate, epoxy resins, nylons, and polyethylene terephthalate. 

The term polymer clay nanocomposite (PCN) refers to a material composed of two-phase materials, where one phase (clay) is dispersed in the second phase (polymer matrix) at a nanometer level. Composites exhibiting structural and compositional changes at the molecular scale have demonstrated several physical property enhancements that are otherwise unavailable in conventional composites. Of these, layered silicates have proven themselves vital as a reinforcing agent when dispersed into engineering plastics. Nanolayers, however, are extremely difficult to disperse in polymer matrices because of their tendency for face-to-face... 

Fu, X.-A., and Qutubuddin, S., Polymer-clay nanocomposites exfohation of organophUic montmoriUonite nanolayers in polystyrene. Polymer, 42, 807-813 (2001). 

Massam J, Pinnavaia TJ (1998) Clay Nanolayer Reinforcement of a Glassy Epoxy... 

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