ABSTRACT
Biodegradable compositions based on natural polymers are widely used in practice. Because of mixing, new physicochemical properties of compositions can arise, which are not inherent to the original components. Innovative technologies use biodegradable system for producing clean construction materials and packagings [4, 5, 10, 11, 12,]. A typical representative of polyhydroxyalkanoates [6] is polyhydroxybutyrate (PHB), along with its useful properties has some undesirable сharacteristics: high cost and fragility. To overcome these limitations its copolymers with poly-(3 hydroxyvalerate) (PHBV), as well as compositions with other biomedical polymers, in particular chitosan. Chitosan, a natural non-toxic biodegradable polymer, produced by deacetylation of chitin, is the second most common biopolymer in nature after cellulose. Chitosan is used in film coatings and membranes to extend the shelf life of foodstuffs. However, a high sensitivity chitosan to moisture limits its applications. This disadvantage can be overcome by mixing chitosan with moisture proof polymers. In this case, however, the material remains biodegradable.
