Patent ID: 7528211
Filing Date: 2009-05-05
Classification: C08G

Abstract:
1. A method for preparing poly(α-hydroxy acids) comprising the following successive steps: i) controlled polymerization of OCA monomers of formula (I) in an anhydrous organic solvent at a temperature in a range of from −20 to 200° C., wherein R 1 and R 2 either identical or different, independently of each other, represent a radical selected from the group formed by hydrogen, C C C C C C R 1 and R 2 form together a radical selected from the group consisting of C 4 -C 14 cycle and fused C 3 -C 14 heterocycle, iii) recovery of the obtained polymer following step i), wherein the polymerization reaction of step i) is performed in a controlled manner in presence of a catalytic system comprising a base, said base being a 5- or 6-membered aromatic heterocycle comprising at least one endocyclic nitrogen atom, with the proviso that when the base is used alone in the catalytic system, it does not represent pyridine, 2-methylpyridine, 2,6-dimethylpyridine, or 2-methoxy-pyridine.