Bimetallic Schiff base complexes for stereoselective polymerisation of racemic-lactide and copolymerisation of racemic-lactide with ε-caprolactone

被引：36

作者：

Sun, Zhiqiang ^{[1
]}

Duan, Ranlong ^{[1
]}

Yang, Jingwei ^{[1
]}

Zhang, Han ^{[1
]}

Li, Shuai ^{[1
]}

Pang, Xuan ^{[1
]}

Chen, Wenqi ^{[1
]}

Chen, Xuesi ^{[1
]}

机构：

[1] Chinese Acad Sci, Changchun Inst Appl Chem, Key Lab Polymer Ecomat, Changchun 130022, Peoples R China

来源：

RSC ADVANCES | 2016年 / 6卷 / 21期

基金：

中国国家自然科学基金;

关键词：

RING-OPENING POLYMERIZATION; HALF-SALEN COMPLEXES; ALUMINUM COMPLEXES; RAC-LACTIDE; LIGANDS; ZINC; INITIATOR; STEREOCONTROL; CATALYSTS; POLYLACTIDES;

D O I：

10.1039/c6ra00289g

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Three pairs of bimetallic Schiff base aluminum complexes (1a-6a) with different tetraamine backbone bridging parts and bulky silyl-substituted moieties on salicylidene were synthesized. Using these complexes as catalysts for ring opening polymerisation (ROP) of racemic-lactide (rac-LA), systematical stereoselectivity and kinetic studies on ROP of rac-LA were carried out. The Gibbs free energy difference between homo-propagation and cross-propagation (Delta G not equal) calculated by activation entropy and enthalpy showed that bulky substituents at the 3-position enhanced the stereoselectivity. And the kinetic study results indicated that bulkier substituents with more steric hindrance reduced the ROP reactivity. Moreover, these complexes could also be used for copolymerisation of rac-LA and epsilon-caprolactone (epsilon-CL). Copolymers of poly(LA-co-CL) with various monomer ratios were synthesized. Kinetic research on copolymerisation as well as microstructure analysis demonstrated that poly (LA-co-CL) achieved by these complexes were tapered block copolymers.

引用

页码：17531 / 17538

页数：8

共 54 条

[1] Ring-opening polymerization of lactide with group 3 metal complexes supported by dianionic alkoxy-amino-bisphenolate ligands: Combining high activity, productivity, and selectivity [J].