Copolyesters and process for their production

摘要: High molecular weight copolymers containing 3-hydroxybutyrate residues, i.e. units of the formula and up to 50 mole % residues other hydroxy acids, viz where n is 0 or an integer and, if = 1 R 2 , 3 4 H, R' not methyl. The are made microbiologically: for part cultivation micro-organism under conditions such that polymer accumulated, e.g. by limitation a nutrient, nitrogen source, required growth but polyester accumulation. For at least this period accumulation substrate acid derivative thereof gives comonomer units. Propionic acid, which polymers 1, =R =H C H s preferred acid.