文献类型：期刊文献

英文题名：Copolymerization of L-lactide and ε-caprolactone catalyzed by mono-and dinuclear salen aluminum complexes bearing bulky 6,6′ dimethylbipheyl-bridge: random and tapered copolymer

作者：Kan, Chao;Ma, Haiyan[1]

机构：[1]E China Univ Sci & Technol, Shanghai Key Lab Funct Mat Chem, 130 Meilong Rd, Shanghai 200237, Peoples R China; E China Univ Sci & Technol, Lab Organometall Chem, 130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2016

卷号：6

期号：53

起止页码：47402

外文期刊名：RSC ADVANCES

收录：;EI(收录号：20162302454733);WOS:【SCI-EXPANDED(收录号:WOS:000377253400025)】；

基金：This work is subsidized by the National Natural Science Foundation of China (NNSFC, 21074032 and 21474028), the Program for New Century Excellent Talents in University (for H. Ma, NCET-06-0413) and the Fundamental Research Funds for the Central Universities (WD1113011). All the financial supports are grate fully acknowledged. H. Ma also thanks the very kind donation of a Braun glove-box by AvH foundation.

语种：英文

外文关键词：Catalysis - Monomers - Aluminum compounds

摘要：The mono-and dinuclear salen aluminum complexes L1-3AlMe (1, 2, 5), (LAlOPr)-Al-2-Pr-i (3), (LAlOBn)-Al-2 (4) and L1-3Al2Me4 (6-8) (L = 6,6'-[(6,6'-dimethyl-[ 1,1'-biphenyl]-2,2'-diyl) bis(nitrylomethilidyne)]-bis(2-R-1-4-R-2-phenol): L-1, R-1 = R-2 = Me; L-2, R-1 = Bu-t, R-2 = Me; L-3, R-1 = R-2 = cumyl) with a racemic 6,6'-dimethylbiphenyl bridge were tested as initiators for the copolymerization of L-LA and epsilon-CL. In the presence of alcohol, the mononuclear aluminum complexes catalyzed the controlled copolymerization in the melt at 110 degrees C, producing practically random copolymers with narrow polydispersity indices (D = 1.03-1.07). Notably, the component of the copolymer produced by complex 3 strictly correlated with the feed ratio of the monomers at different stages of the copolymerization. In a 50/50 feed ratio of L-LA/ epsilon-CL, the reactivity ratios of the two monomers are r(LA) = 1.17, r(CL) = 0.80. The average lengths of the lactidyl and caproyl sequences in the resultant copolymer are L-LA = 1.91, L-CL = 1.93. Even at 180 degrees C, the copolymerization initiated by complex 3 was still well-controlled, producing random copolymers with narrow dispersity indices (D = 1.07-1.09). Compared with the mononuclear counterparts, the dinuclear aluminum methyl complexes enable a few fold boost in activity because of the lower steric hindrance around the aluminum centers, but gave tapered copolymers with broadened D values (D = 1.12-1.22).