Synthesis and Characterization of Sodium Complexes Supported with NNO-Tridentate Schiff Base Ligands and Their Application in the Ring-Opening Polymerization of L-Lactide

• Main Authors: Kai-Hsuan Lo, 羅開軒
• Other Authors: Chu-Chieh Lin
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/90896811387546751008

碩士 === 國立中興大學 === 化學系所 === 103 === A series of sodium complexes supported by NNO-tridentate schiff base ligands were synthesized and characterized by NMR spectroscopy and Elementary Analysis (EA).Single crystal of 1, 2, and 5 X-ray diffraction revealed that the molecular structures of three complexes were dinuclear binding phenolate-O-bridged. The application of these complexes in ring-opening polymerization (ROP) of L-Lactide (L-LA) has been investigated. Experimental results indicated that the polymerization of L-Lactide catalyzed by complex 1 ~ 8 in the presence of benzyl alcohol (BnOH) showed high reactivity and yielded polylactide with low polydispersity index (PDI = 1.12 ~ 1.20).It was found that complex with the higher sterically hindered group and higher electron-donating ability substitution groups, the higher reactivity in ROP it will be. The number averge molecular weight (Mn) of polylactides is linearly increasing by increasing the monomer-to-initiator ratios.The polymerization kinetics using complex 5 as catalyst in the presence of benzyl alcohol was studied in detail. The mechanism was proposed based on the kinetics studies, NMR and DOSY-PGSE evidence.