三(2,6-二叔丁基-4-甲基苯氧基)镧配合物催化合成星形聚己内酯

Synthesis of Star Poly(ε-caprolactone) Catalyzed by Lanthanum Tris(2,6-di-tert-butyl-4-methylphenolate)

分别以三乙醇胺和四乙醇乙二胺为引发剂,用三(2,6-二叔丁基-4-甲基苯氧基)镧(La(DBMP)3)作催化剂,催化ε-己内酯开环聚合,制备了三臂和四臂星形聚己内酯.通过1HNMR表征了聚合物的星形结构以及分子量.研究表明,每一个催化剂分子可与多个引发剂分子作用,当三乙醇胺与La(DBMP)3的摩尔比值为1.7～6.4时,均可制得纯净的三臂星形聚己内酯.通过调节ε-己内酯与多元醇的摩尔比值,可以改变星形聚己内酯的分子量,实现聚合产物分子量可控.

Tri- and tetra-arm star poly（ε-caprolactone）s have been successfully synthesized by ring-opening polymerization of ε-caprolactone using triethanolamine or N, N, N＇, N＇-tetrakis- （2-hydroxyethyl） ethylenediamine （HEA） as the multifunctional initiator and lanthanum tris（2,6-di-tert-butyl-4-methylphenolate） （La（DBMP）3） as the catalyst. In ^1H NMR analysis, compared with triethanolamine and HEA molecules, the chemical shifts of the hydrogen （N（CHaCHaO）n, n = 3, 4） in star poly（ε-caprolactone）s moved from 3.65 to 4.10, suggesting the direct linkage between the poly （ε-caprolactone） arm and the initiator. When the molar ratio of triethanolamine to La（DBMP）3 ranged from 1.7 to 6.4, pure tri-arm star poly（ε-caprolactone） could be prepared, which indicates that one catalyst molecule could co-work with several initiator molecules. The molecular weights of star poly（ε-caprolactone） were determined by ^1H NMR end group analysis, which are very close to the values calculated from the molar ratio of ε-caprolactone to the initiator.