Comonomer‐Unit Compositions, Physical Properties and Biodegradability of Bacterial Copolyhydroxyalkanoates

Summary: The comonomer‐unit compositions and their distribution of as‐produced bacterial copolyesters, including poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate), poly(3‐hydroxy‐butyrate‐co‐3‐hydroxypropionate), poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) and poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) are described in this paper. Each copolyester sample can be comonomer‐unit compositionally fractionated into several fractions, indicating that the original copolymers are mixtures of copolymers with different comonomer‐unit compositions. The effects of comonomer‐unit compositional distribution on thermal properties, crystallization, biodegradability and solid‐state phase behavior are investigated using comonomer compositionally fractionated copolymers. The trend shown by the Tm values of the copolymers, P(3HB‐co‐3HV), P(3HB‐co‐3HP), P(3HB‐co‐3HH) and P(3HB‐co‐4HB), plotted against the content of the second monomer unit. image The trend shown by the Tm values of the copolymers, P(3HB‐co‐3HV), P(3HB‐co‐3HP), P(3HB‐co‐3HH) and P(3HB‐co‐4HB), plotted against the content of the second monomer unit.