Ring-opening polymerization and block copolymerization of L-lactide with divalent samarocene complex
writer：Cui, DM；Tang, T；Bi, WG；Cheng, JH；,Chen, WQ；Huang, BT
keywords：ring-opening polymerization，copolymerization， block copolymers， catalysts， L-lactide， lanthanocene complexes
source：期刊
specific source：http://onlinelibrary.wiley.com/doi/10.1002/pola.10814/abstract;jsessionid=41B4E08AF8F394E927C3DE5757
Issue time：2003年
Divalent samarocene complex [(C5H9C5H4)2Sm(tetrahydrofuran)2] was prepared and characterized and used to catalyze the ring-opening polymerization of L-lactide (L-LA) and copolymerization of L-LA with caprolactone (CL). Several factors affecting monomer conversion and molecular weight of polymer, such as polymerization time, temperature, monomer/catalyst ratio, and solvent, were examined. The results indicated that polymerization was rapid, with monomer conversions reaching 100% within 1 h, and the conformation of L-LA was retained. The structure of the block copolymer of CL/L-LA was characterized by NMR and differential scanning calorimetry. The morphological changes during crystallization of poly(caprolactone) (PCL)-b-P(L-LA) copolymer were monitored with real-time hot-stage atomic force microscopy (AFM). The effect of temperature on the morphological change and crystallization behavior of PCL-b-P(L-LA) copolymer was demonstrated through AFM observation.