More about the polymerization of lactides in the presence of stannous octoate

摘要: The ring-opening polymerization of lactide cyclic monomers in the bulk presence tin(II) 2-ethylhexanoate (stannous octoate or SnOct2) was reexamined under conditions allowing for end group characterization growing chains by high-resolution 1H-NMR. Data collected low values monomer/initiator (M/I) ratio showed that DL-lactide ring opened to yield lactyl octoate-terminated short chains. A cationic-type mechanism involving co-initiation octanoic acid proposed account experimental findings. formation a side product, hydroxytin(II) lactate (HTL), found which appeared able initiate and high molecular weight PLA50 polymer. However with stannous faster than HTL one. Anyhow, data suggested both SnOct2 are likely act simultaneously as initiators during lactides SnOct2. complete reaction scheme various compounds be formed these conditions. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Chem 35: 3431–3440,