ICCAS OpenIR
Stereoselective polymerization of rac-lactide with a bulky aluminum/Schiff base complex
Tang, ZH; Chen, XS; Yang, YK; Pang, X; Sun, JR; Zhang, XF; Jing, XB
2004-12-01
Source PublicationJOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
ISSN0887-624X
Volume42Issue:23Pages:5974-5982
AbstractAn aluminum/Schiff base complex {[2,2-dimethyl-1,3-propylenebis(3,5-di-tert-butylsalicylideneiminato)](isopropanolato)aluminum(III) (2)} based on a bulky ligand and aluminum isopropoxide was prepared and employed for the stereoselective ring-opening polymerization (ROP) of rac-lactide (rac-LA). The initiator was characterized with nuclear magnetic resonance (NMR), crystal structure measurements, and elemental analysis. It contained a five-coordinate aluminum atom that was trigonal bipyramidal in the solid state according to the crystal structure measurements. The two conformational stereoisomers of 2 exchanged quickly on the NMR scale. Compound 2 polymerized rac-LA into a crystalline polymer that was characterized with H-1 NMR, wide-angle X-ray diffraction, electrospray ionization mass spectrometry, and gel permeation chromatography. The kinetics of the polymerization were first-order in both the monomer and initiator, and there was a linear relationship between the rac-LA conversion and the number-average molecular weight of poly(rac-LA) with a narrow molecular distribution (1.04-1.08). These features showed that the polymerization was well controlled. The high melting temperature (196-201 degreesC) and isotacticity of poly(rac-LA) indicated that complex 2 was a highly stereoselective initiator for the ROP of rac-LA. The stereoselectivity was as high as 90%, and the stereoblocks of poly(rac-LA) by complex 2 contained an average of 20 units (average block length = 20) of enantiomerically pure lactic acid. The activation energy (23.6 kJ mol(-1)) was obtained according to an Arrhenius equation. (C) 2004 Wiley Periodicals, Inc.
KeywordInitiators Rac-lactide Ring-opening Polymerization Kinetics Stereoselective
Indexed BySCI
Language英语
WOS IDWOS:000225201300014
PublisherJOHN WILEY & SONS INC
Citation statistics
Document Type期刊论文
Identifierhttp://ir.iccas.ac.cn/handle/121111/81580
Collection中国科学院化学研究所
Corresponding AuthorChen, XS
AffiliationChinese Acad Sci, Grad Sch, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Peoples R China
Recommended Citation
GB/T 7714
Tang, ZH,Chen, XS,Yang, YK,et al. Stereoselective polymerization of rac-lactide with a bulky aluminum/Schiff base complex[J]. JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY,2004,42(23):5974-5982.
APA Tang, ZH.,Chen, XS.,Yang, YK.,Pang, X.,Sun, JR.,...&Jing, XB.(2004).Stereoselective polymerization of rac-lactide with a bulky aluminum/Schiff base complex.JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY,42(23),5974-5982.
MLA Tang, ZH,et al."Stereoselective polymerization of rac-lactide with a bulky aluminum/Schiff base complex".JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 42.23(2004):5974-5982.
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