Anionic polymerisation lactones

By the attack of an anion to the lactone cycle (anionic polymerisation), carbonyl - oxygen scission and carbon - oxygen scission are possible ... 

The anionic polymerisation of small- and medium-sized lactones was reported to be fast (4-, 6- and 7-membered) when compared with macrolactones (12-, 13- and... 

The lactones, the cyclic esters of hydroxy acids have been polymerised with various catalysts anionic catalysts, cationic catalysts and organometallic catalysts [28, 29, 39, 45, 54]. Five member lactone rings are unpolymerisable. Four, seven or eight member lactones are polymerisable [28, 29, 39, 45, 54]. 

During the anionic or anionic coordinative polymerisation of lactones, there is a permanent equilibrium (8.31) between the alcoholate groups and hydroxyl groups from the reaction system ... 

Figure 21.1 Possible mechanisms for anionic ring-opening polymerisations of non-substituted lactones showing both acyl-oxygen scission (a) as well as alkyl-oxygen scission (b).

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