Protein/Clay Nano-Biocomposites

In the current context, protein-based materials might be considered as an alternative to the petroleum-based plastics since fully biodegradable and characterized by remarkable functional properties that can be exploited in a wide range of non-food applications. To improve their performances that are often restricted by high water sensitivity and low mechanical properties, a relevant strategy consisted in the development of protein/clay nanocomposite. For this purpose, several examples of protein-based nano-biocomposites were presented with a special attention for the methods used for the incorporation of layered silicates (organically modified or not) into the matrices and the ultimate functional properties exhibited by the resulting materials. In terms of mechanical properties, the addition of nanoclays leads to a significant improvement of material performance with an increase of Young's modulus and tensile strength ranging between 1.5 and 2 times. As regards as barrier properties, the improvement appeared quite moderate in spite of a rather good dispersion of layered silicates that would be expected to result in a tortuous pathway limiting diffusion of gases molecules. Thus, a two-fold reduction in water vapour permeability was obtained, and the same or no effect in the case of permeability toward O2 and CO2.