Premium
Lipase‐catalyzed polymerization of L ‐lactide in ionic liquids
Author(s) -
YoshizawaFujita Masahiro,
Saito Chihiro,
Takeoka Yuko,
Rikukawa Masahiro
Publication year - 2008
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1217
Subject(s) - lipase , yield (engineering) , polymerization , ionic liquid , catalysis , materials science , solvent , toluene , polymer , polymer chemistry , molar mass distribution , lactide , nuclear chemistry , organic chemistry , chemistry , enzyme , composite material
Lipase‐catalyzed polymerizations of L ‐lactide were carried out in four kinds of ionic liquids (ILs) in order to investigate the effect of ILs on the conversion, molecular weight, and yield of the obtained poly(lactide) (PLLA). PLLA could be synthesized in ILs of 1‐butyl‐3‐methylimidazolium ([C 4 mim]) except in [C 4 mim][N(CN) 2 ]. While the number‐average molecular weight ( M n ) of the PLLA obtained in [C 4 mim][PF 6 ] was below 4000 g mol −1 and the yield was below 10%, the M n and yield of the PLLA obtained in [C 4 mim][BF 4 ] reached 55000 g mol −1 and 35%, respectively. The M n values of PLLAs in the ILs were clearly higher than those of PLLAs obtained in bulk and in toluene (<44000 g mol −1 ). The polymerization in the ILs proceeds even at lower temperatures as compared with that in bulk. The effect of lipase content on the M n of PLLA was also investigated. When [C 4 mim][BF 4 ] was used as the solvent, the highest M n was obtained at a lipase content of 10 wt%. In the case of [C 4 mim][NTf 2 ], the most suitable lipase content depended on the polymerization temperature. [C 4 mim][BF 4 ] was suitable to obtain higher molecular weight PLLA and higher polymer yield at lower lipase contents. Copyright © 2008 John Wiley & Sons, Ltd.