文献类型：期刊文献

英文题名：Polymerization of ε-Caprolactone and Copolymerization with rac-Lactide Catalyzed by Mono(amidinate) Aluminum Complexes

作者：Qian Feng[1];Liu Keyin[1];Ma Haiyan[1]

机构：[1]E China Univ Sci & Technol, Inst Appl Chem, Lab Organometall Chem, Shanghai 200237, Peoples R China

年份：2011

卷号：32

期号：1

起止页码：189

外文期刊名：CHINESE JOURNAL OF CATALYSIS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000287107200031)】；

语种：英文

外文关键词：aluminum amidinate complex; epsilon-caprolactone; rac-lactide; ring-opening polymerization; copolymerization

摘要：Mono(amidinate) aluminum complexes showed high catalytic activity for the ring-opening polymerization of e-caprolactone in toluene at ambient temperature. Monomer conversion up to 91% could be reached within 1 h when using [{PhC(N-2,6-(Pr2C6H3)-Pr-i)(2)}AlMe2] (C1) as initiator at 25 degrees C. The electron-donating groups on the ortho-positions of the N-substituted phenyl ring were superior to the electron-withdrawing groups for the enhancement of the catalytic activity, but both brought an increase in activity when compared with the un-substituted complex C7. The complexes bearing two ortho-substituents on one of the N-phenyl rings were more active than the analogues bearing one ortho-substituent. Although high molecular weight poly(epsilon-caprolactone)s were obtained by using these aluminum catalysts, the polymerization of epsilon-caprolactone was not well controlled as indicated by the broad molecular weight distributions (PDI = 1.43-1.85) and the deviation of the number average molecular weight from the theoretical values. Sequential copolymerization of e-caprolactone and rac-lactide using mono(amidinate) aluminum complexes afforded poly(epsilon-caprolactone)-poly(rac-lactide) diblock copolymer, which was characterized well by NMR spectroscopy and gel permeation chromatography analysis.