Abstract: The present invention relates to a process for the preparation of a composition comprising aliphatic polyester by ring-opening polymerization of cyclic ester monomers, said process comprising the steps of: (a) providing cyclic ester monomers and polymerization catalyst to a reactor, (b) melt polymerizing said cyclic ester monomers to form a composition comprising aliphatic polyester, (c) stabilizing the composition against aliphatic polyester depolymerization by incorporating therein or applying thereto at least one stabilizing agent, thereby obtaining a melt-stable composition, and (d) optionally removing at least a portion of the residual cyclic ester monomers; wherein said stabilizing agent is a compound of formula (I) wherein R1, R2, R3, m, R4, R5, and R6 are as defined in the claims.

Abstract: A process for purifying meso-lactide including purifying meso-lactide, wherein the free acid content is at least 30 meq/kg including at least one step of subjecting a feed including at least 75 wt. % meso-lactide to solvent crystallisation followed by product meso-lactide recovery, wherein the solvent crystallisation is carried in a solvent including at least 70 wt. % of at least one compound selected from the group of ketones of the formula R1-C(?O)—R2, the solvent amounts to 5-50 wt. % of feed and solvent total, the solvent crystallisation conditions being at least 15% of the meso-lactide in the feed crystallises in solid form, wherein the solid meso lactide recovered from solvent crystallisation followed by recovery of product meso-lactide has a free acid content of at most 20 meq/kg. The process yields meso-lactide in high purity and high yield in an efficient manner, with minimum formation of lactic and linear lactic acid oligomers.

Abstract: The present invention relates to a process for the preparation of a composition comprising aliphatic polyester by ring-opening polymerization of cyclic ester monomers, said process comprising the steps of: (a) providing cyclic ester monomers and polymerization catalyst to a reactor, (b) melt polymerizing said cyclic ester monomers to form a composition comprising aliphatic polyester, (c) stabilizing the composition against aliphatic polyester depolymerization by incorporating therein or applying thereto at least one stabilizing agent, thereby obtaining a melt-stable composition, and (d) optionally removing at least a portion of the residual cyclic ester monomers; wherein said stabilizing agent is a compound of formula (I) wherein R1, R2, R3, m ,R4 , R5, and R6 are as defined in the claims.