[Composite biodegradable materials based on polyhydroxyalkanoate]

Conditions for the processing and mixing of biodegradable polymers at temperatures less than their thermal destruction (130-150 degrees C) using standard equipment have been identified. The structure of the polyhydroxybutyrate/valerate (PHB/V) copolymer has been revealed and peculiarities of the crystal phase formation at different monomer ratios have been investigated. It was shown that pure PHB with molecular mass 180-270 kDa has elastic module approximately 1.2 GPa, strength approximately 25 MPa, and elongation at break approximately 10%. The most active biodestructors of PHB, PHB/V, and their composites have been selected (Aspergillus caespitosus), and the ability of basidiomycete Panus tigrinus to biodegrade polyalkanoates was demonstrated for the first time. It was shown that A. caespitosus degraded PHB/V and Biopol films along with the PHB with the destruction rate depending on the technology of the film production, on the molecular mass, and on the extend of the polymer crystallinity.