A series of rare earth phenolates substituted by alkyl groups for D,L-lactide ring-opening polymerization

Abstract

Single component rare earth phenolates substituted by various alkyl groups have been prepared and the correlation between the aryloxides’ structure and catalytic activity in the ring-opening polymerization of D, L-lactide has also been investigated. The catalytic activity of all rare earth aryloxides, characteristics of the ring-opening polymerization as well as polymerization kinetics and mechanism were investigated. The results showed that both phenolates’ catalytic activities and polymerization characteristics changed regularly, keeping in good concordance with variations in substitutents’ number on phenol and structure of aryloxide ligands. The stronger ability of electron-donation of alkyl groups, the higher catalytic activity. Moreover, the more numbers of substituted alkyl on phenyl ring, the higher catalytic activity. The analyses of polymer ends revealed that the polymerization proceeded via a coordination-acyl-oxygen bond cleavage-insertion mechanism.

Keywords

ring-opening polymerization / D, L-lactide / rare earth phenolates

References

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