TY - GEN
T1 - Melt polycondensation and analysis of hydroxyl-terminated poly(L-lactic acid) using small molecular diols as terminating agents
AU - Che, Jing
AU - Yang, Rong Jie
PY - 2013
Y1 - 2013
N2 - The synthesis of hydroxyl-terminated poly(L-lactic acid) (PLLA) by direct melt polycondensation of L-lactic acid and use of small molecular diols as terminating agents was investigated. L-lactic acid was dewatered to prepare the dehydrated prepolymer at first. Then PLLA was prepared through melt polycondensation in a melt with catalyst system including TSA, SnCl2 and Sn(Oct)2. Finally, ethylene glycol, 1,4-butanediol, and 1,8-octanediol, respectively, were used in hydroxyl termination of the PLLA. The molecular weights and end-group structures of all products were characterized by gel permeation chromatography (GPC) and 1H-NMR. DSC and Disc Polarimeter were used to characterize crystallinity and racemization, respectively. The results show that two kinds of hydroxyl-terminated PLLA polymers were obtained: complete hydroxyl-terminated PLLA prepared by using ethylene glycol or 1,4-butanediol, incomplete hydroxyl-terminated PLLA prepared by using 1,8-octanediol or combination of two kinds of diols. Combination of ethylene glycol or 1,4-butanediol with 1,8-octanediol can reach high hydroxyl termination of PLLA, and maintain the molecular weight by decrease of alcoholysis at the same time. 1H-NMR was found as an effective estimating way for extents of reactions. The hydroxyl-terminating reactions of PLLA by the diols reduced the crystallinity and resulted in racemization to some extent.
AB - The synthesis of hydroxyl-terminated poly(L-lactic acid) (PLLA) by direct melt polycondensation of L-lactic acid and use of small molecular diols as terminating agents was investigated. L-lactic acid was dewatered to prepare the dehydrated prepolymer at first. Then PLLA was prepared through melt polycondensation in a melt with catalyst system including TSA, SnCl2 and Sn(Oct)2. Finally, ethylene glycol, 1,4-butanediol, and 1,8-octanediol, respectively, were used in hydroxyl termination of the PLLA. The molecular weights and end-group structures of all products were characterized by gel permeation chromatography (GPC) and 1H-NMR. DSC and Disc Polarimeter were used to characterize crystallinity and racemization, respectively. The results show that two kinds of hydroxyl-terminated PLLA polymers were obtained: complete hydroxyl-terminated PLLA prepared by using ethylene glycol or 1,4-butanediol, incomplete hydroxyl-terminated PLLA prepared by using 1,8-octanediol or combination of two kinds of diols. Combination of ethylene glycol or 1,4-butanediol with 1,8-octanediol can reach high hydroxyl termination of PLLA, and maintain the molecular weight by decrease of alcoholysis at the same time. 1H-NMR was found as an effective estimating way for extents of reactions. The hydroxyl-terminating reactions of PLLA by the diols reduced the crystallinity and resulted in racemization to some extent.
KW - Diols
KW - Hydroxyl-terminated
KW - Melt polycondensation
KW - Poly(L-lactic acid)
UR - http://www.scopus.com/inward/record.url?scp=84880142754&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/AMM.328.890
DO - 10.4028/www.scientific.net/AMM.328.890
M3 - Conference contribution
AN - SCOPUS:84880142754
SN - 9783037857120
T3 - Applied Mechanics and Materials
SP - 890
EP - 894
BT - Mechanical Science and Engineering III
T2 - 2013 3rd International Conference on Mechanical Science and Engineering, ICMSE 2013
Y2 - 1 March 2013 through 3 March 2013
ER -