Clay polymer nanocomposites food packaging

Polymer-clay nanocomposites (PCN) are a class of hybrid materials composed of organic polymer matrices and organophilic clay fillers, introduced in late 1980s by the researchers of Toyota (Kawasumi, 2004). They observed an increase in mechanical and thermal properties of nylons with the addition of a small amount of nano-sized clays. This new and emerging class of pol miers has found several applications in the food and non-food sectors, such as in constmction, automobiles, aerospace, military, electronics, food packaging and coatings, because of its superior mechanical strength, heat and flame resistance and improved barrier properties (Ray et al., 2006). 

Ray, S., Quek, S. Y, Easteal, A., Chen, X. D. (2006). The potential use of polymer-clay nanocomposites in food packaging. International Journal of Food Engineering, 2, 1-11. 

The incorporation of impermeable clay particles into PET (which is a semicrystalline polymer) can improve the barrier properties of PET nanocomposites towards gases and water vapor. This, in turn, results in outstanding property improvements in terms of a decreasing water permeability for food packaging and an increasing flame resistance. When a new system of saturated polyesters... 

The principal used in polymer-clay nanocomposites leads the individual clay layers as well as the polymer chains to function more effectively with numerous improved properties such as high moduli, increased strength and heat resistance, decreased gas permeability and flammability, increased biodegradability of biodegradable polymers, and attractive electrical properties when compared to virgin polymers or conventional micro- and macrocomposites [37]. These properties make them ideal materials for applications in food packaging, structural automotive components, and electronics among others. 

Barrier films of exfoliated clay-polymer composites have been a subject of considerable investigation with some commercial utility (e.g., barrier layer for termis balls).The thin exfoliated clay platelets dispersed in a polymer matrix present a tortuous diffusion path for gas molecules similar to that observed in Figure 12 for biaxially oriented polymer blends. The advantages of exfoliated clay modification for barrier properties are the retention of transparency and low cost. A novel approach utilizing nanocomposites involves dispersion of the exfoliated clay in a water emulsion or suspension and coating a desired substrate. This approach has been commercialized by IntMat for tennis balls, tires, and food packaging applications. For exceptional barrier properties, and where transparency is not required, metalized polymer films or aluminum foil polymer film laminates are usually employed. 

Fang XY, Domenek S, Ducruet V et al (2013) Diffusion of aromatic solutes in aliphatic polymers above glass transition temperature. Macromolecules 46(3) 874-888 Farhoodi M, Mousavi SM, Sotudeh-Gharebagh R et al (2013) Migration of aluminum and silicon from PET/clay nanocomposite bottles into acidic food simulant. Packag Technol Sci. doiilO. 1002/pts.2017... 

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