申请人:IMPERIAL CHEMICAL INDUSTRIES PLC
公开号:EP0052459A1
公开(公告)日:1982-05-26
High molecular weight copolymers containing β-hydroxybutyric acid residue, i.e. units of the formula
and up to 50 mole % of residues of other hydroxy acids, viz units of the formula
where n is 0 or 1 and, if n = 1 and R2, R3, and R4 = H, R2 is not methyl.
The copolymers are made microbiologically: for part of the cultivation the micro-organism is under conditions of limitation of a nutrient, e.g. nitrogen source, required for growth but not polyester accumulation. For at least part of this period of growth limitation the substrate is an acid or a salt thereof that tives the comonomer units. Propionic acid, which gives polymers where n = 1, R2=R3=R4=H and R1= C2H2, is the preferred acid.
高分子量共聚物,含有 β-羟基丁酸残基(即式中的单元)和高达 50 摩尔 % 的其他羟基酸残基(即式中的单元)。
和最多 50 摩尔%的其他羟基酸残基,即式中的单位
其中 n 为 0 或 1,如果 n = 1 且 R2、R3 和 R4 = H,则 R2 不是甲基。
共聚物是通过微生物方法制成的:在部分培养过程中,微生物处于生长所需的养分(如氮源)受限的条件下,但不积累聚酯。至少在生长受限的部分时间内,底物是一种酸或其盐,这种酸或盐可以生成共聚单 元。丙酸是首选的酸,它可以产生 n=1, R2=R3=R4=H 和 R1=C2H2 的聚合物。