Polysaccharides, modified polysaccharides and polysaccharide blends for biodegradable materials

Abstract

The authors have focused on the production and characterization of biopolymers, followed by chemical derivatization of these polymers to obtain new functional characteristics including higher strength and reduced solubility in water. The two primary polysaccharide polymers under study are pullulan (linear alpha-linked D-glucan with 1,4-linked maltotriose and maltotetraose units connected by 1,6-linkages) and chitosan (linear beta-1,4 linked 2-amino-2-deoxy-D-glucose). Chemical derivatization and crosslinking reactions were developed to improve the properties. Blends of pullulan with another biodegradable polymer, polyhydroxybutyrate/polyhydroxyvalerate (PHBV), a bacterial polyester, were made to see if the PHBV component would improve film flexibility while the pullulan component would increase biodegradability and adhesiveness to other natural polymers such as cellulose. Crosslinked chitosan was synthesized to overcome the problem with water uptake and improve mechanical properties of films.