Chitosan is a carbohydrate obtained by treating shells of shrimp and other shellfish with an alkaline solution. It is being increasingly used as an alternative material for packaging films. Alginates are salts (mostly sodium) of alginic acid, a polysaccharide consisting of glycosidic linkages of mannuronic acid and guluronic acid found in brown algae. While traditionally used as food additives and edible films, alginates recently found applications as plastics, mostly bags, although their potential in biomaterials and flexible electronics have also been reported. The above discussed naturally occurring polysaccharides have inadequate mechanical strength compared to most fossil-based plastics. Even when formulated with reinforcing fillers, impact modifiers, and/or other polymers, as they typically are, their applications as bioplastics have largely been limited to packaging materials. Other naturally occurring plant-based polymers, such as chitin and lignin, are used predominantly as fillers rather than as plastic matrices. 31, 32