Types of Techniques for Modifying Starch-Based Biodegradable Plastics

The growing concerns about wasting natural resources and the increasing enviromental issues in the world due to the usage of petro-based materials, have led to the advent of bio-degeradable material usage for food packaging.Starch is one the most important polysaccharides which has been widely used for bio-degeradable-film production. the starch-based films are flexible and strong, but the presence of free hydroxyl groups in starch structure, is the reasonf for these films to be hydrophil and due to reduced mechanical strenght and low elasticity is limiting the usage of starch in packaging industries.The purpose of this study is to find ways to improve the properties of films composed of starch. In general, modification techniques, including plastic softners, co-polymers, nano-composites and mixing with other bio-polymers it is possible to modify the functional properties of starch to obtain better films from it. some of these favorable properties are: reducing moisture absorption, water vapour permiability, heat stability, increasing the hydrophobicity, etc. recently,   Non-thermal processes specially cold-plasma have been used for modifying the starch films with good results.