“Green” nano-composite materials - new possibilities for bioplastics 1

Research in the area of biological renewable materials has shown that the main building blocks of life – carbohydrates, fats, proteins, and their derivatives - could substitute products from traditional nonrenewable sources. However its realization will need significant and continuous improvement of those materials. Problems of applications of bioplastics arise not only from the (price) competition with the highly developed synthetic polymers but also from their, up to now not sufficient property levels. Possibilities to decrease the hydrophilicity and to increase the values of mechanical properties so far are: i) application of hydrophobic coating(s); ii) blending with different, biodegradable synthetic polymers (polyesters) and iii) new ways of reactive extrusion of natural. A new possibility in this direction is seen in the creation of composite materials of thermoplastic organic biopolymer and nanoscopic inorganic particles incorporated on a molecular scale. This paper will show the results of the first experiments to get nano-scale starch/clay composites. The starch will be fully gelatinized and the modified clay can be dispersed homogeneously on a truly nanoscale. Therefore all requirements of a significant increase in mechanics and a decrease in permeability of this composite material are present.