Preparation, properties, and utilization of biobased biodegradable Nodax copolymers

Bio-catalytic preparation, physical and biological properties, and potential utilization of novel Nodax copolymers are discussed. Nodax is a family of bacterially produced polyesters comprising 3-hydroxybutyrate (3HB) andmedium-chain-length 3-hydroxyalkanoate (mcl-3HA) units. The biosynthesis of PHA copolymers involve parallel enzymatic production of 3-hydroxybutyryl CoA and 3-hydroxyacyl CoA units via fatty acid biosynthesis and fatty acid oxidation followed by enzymatic copolymerization. PHAs are fully biodegradable under both aerobic and anaerobic conditions. The incorporation of mcl-3HA units effectively lowers the crystallinity and T m in a manner similar to the effect of alpha olefins in linear low density polyethylene. The lowered T m well below the thermal decomposition temperature of PHA makes this material easier to process. The reduced crystallinity provides the ductility and toughness required for many applications. Versatile physical properties of Nodax PHA copolymers are well suited for the production of broad ranges of articles. Furthermore, ductile PHA can be blended with other degradable polymers like polylactic acid to greatly enhance their properties.