| abstract |
Process for the preparation of a polyhydroxyalkanoate (PHA) polymer by ring-opening polymerization of a lactone such as beta-butyrolactone, preferably racemic, in which the polymerization is carried out in the presence of an initiator of formula (II) : in which: - R <3> represents an alkyl group from 1 to 15C such as a methyl, ethyl, i-propyl, n-propyl, n-butyl, i-butyl, t-butyl group; a benzyl group; - R1 and R2 which are identical or different each represent a group chosen from alkyl groups from 1 to 15C, such as methyl, t-butyl; cumyle; (alpha, alpha-dimethylbenzyl); adamantyl; trityl; and trialkylsilyl; - X represents O (R4), S (R4) or N (R4) (R5) where R4 and R5 each independently represent an alkyl group of 1 to 15C such as a methyl or ethyl group; or benzyl group, - M is a metal from group 3 of the periodic table of the elements such as Y, La or Nd.Polymers obtainable by this process, compositions using them and use of these polymers and compositions. |