Abstract
1.A series of aluminum catalysts supported by various amide ligands was synthesized and applied in ring-opening polymerization of e-caprolactone (CL). The results indicated all aluminum complexes exhibited catalytic activity in polymerization of e-caprolactone. The catalytic activity of Al complexes was highly influenced by different amide ligands and the catalyst, LMeO-C-OMeAlMe2, showed highest catalytic activity in the ROP of CL (conv.= 90% in 1 h, kobs. = 4.23×10-2 min-1) using benzyl alcohol as initiator. Other cycloester monomers such as valerolactone and 2-bromo-e-caprolactone were also be catalyzed effectively by LMeO-C-OMeAlMe2 to afford polyvalerolactone and poly-2-bromo-e-caprolactone. In addition, various initiators with special target molecules such as N,N-dimethyl-ethanolamine, 2-((2-hydroxyethyl)disulfanyl)ethyl-2-bromo-2-methylpropanoate (HOSSBr), 6-hydroxyhexyl-2-bromo-2-methyl propanoate(HOCCBr), and PEG600 derivative (OHSSOH) bis(2-hydroxyethyl)disulfide, PEG200 were also successfully used in polymerization with CL by LMeO-C-OMeAlMe2. This study proved LMeO-C-OMeAlMe2 was the best choice of catalyst owning high catalytic activity toward e-caprolactone polymerization. 2.Highly polar organic molecules, such as diols, were too protic to undergo ring-opening polymerization (ROP) with lactide (L-LA) homogenously. This study is the first breakthrough that diols can be co-polymerized with LA precursor effectively by using the sodium-typed amide catalysts, whichs are low Lewis acidic, combined with the THF/DMSO co-solvent method. A series of sodium catalysts supported by various amide ligands was synthesized and applied in ring-opening polymerization of L-LA. The results indicated all sodium complexes exhibited catalytic activity in polymerization of L-LA. The catalytic activity of Na complexes was highly influenced by different amide ligands and the catalyst, LMeO-C-TolNa, showed the highest catalytic activity in ROP of L-LA. In addition, various diols such as 1,4-benzenedimethanol, ethylene glycol, 2-hydroxyethylether, and pentarythritol were also successfully co-polymerized with LA by LMeO-C-TolNa. This study initiated the co-ROP of LA and diols under protic condition and LMeO-C-TolNa was the best catalyst due to its high catalytic activity and low toxicity suitable for medical polymer materials production.
Published Version
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