Chem. J. Chinese Universities ›› 2006, Vol. 27 ›› Issue (2): 352.

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Stereoselective Polymerization of rac-Lactide Initiated by Achiral Schiff-base Isopropoxide Aluminum Complex

YANG Yong-Kun,  Tang-Chao-Hui,  PANG-Hui,  Du-Hong-Zhi,  Chen-Xue-Si,  Jing-Xia-Bin   

  1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of  Applied Chemistry,
    Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022, China
  • Received:2005-04-08 Online:2006-02-10 Published:2006-02-10
  • Contact: Chen-Xue-Si,E-mail: xschen@ciac.jl.cn

Abstract:

Abstract An achiral Schiff-base isopropoxide aluminum complex(Ⅱ) was used for the stereoselective ring-opening polymerization of rac-lactide. The kinetics studies indicated that rac-lactide polymerization was first order kinetics to monomer concentration. There was linear relationship between the monomer conversion and molecular weights(Mn) of the polymer with a narrow molecular distribution. These phenomena indicated that the polymerization was well controllable. Moreover, the obtained poly(rac-lactide) was crystalline polymer with relative high tm(179 ℃). 13C NMR and homonuclear decoupled 1H NMR spectra revealed that the polymerization of rac-lactide initiated by complex(Ⅱ) resulted in the isotactic stereoblock polymer, which contained blocks with an average of 11 units of enantiomerically pure lactic acid.

Key words: KeywordsAchiral Schiff-base isopropoxide aluminum complex; rac-Lactide; Stereoselective polymerization;Biodegradable polymer

CLC Number: 

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