Bulk polymerization of lactides initiated by aluminium isopropoxide, 2. Beneficial effect of lewis bases and transfer agents

✍ Scribed by Philippe Degée; Philippe Dubois; Robert Jérôme

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 519 KB
• Volume: 198
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1997.021980623

✦ Synopsis

Abstract

A high increase in the bulk polymerization rate of L,L‐lactide and racemic D,L‐lactide is observed when aluminium isopropoxide is added with an equimolar amount of a Lewis base, such as triphenylphosphine (P(ϕ)~3~) and better 4‐picoline (C~6~H~7~N). Polylactide of high molecular weight and narrow molecular weight distribution is accordingly prepared in a controlled manner when the Al(OiPr)~3~ · C~6~H~7~N combination is used as an initiator over a large temperature range from 110 to 180°C. A secondary alcohol, such as 2‐propanol, has proved to be an efficient transfer agent, which allows the amount of Al per kg of polylactide to be advantageously reduced. All the alcohol molecules participate in the ring‐opening polymerization even at an [iPrOH]~0~/[Al] ratio as high as 10^3^.