TY - JOUR
T1 - Composition analysis of poly(ethylene glycol)-poly(L-lactide) diblock copolymer studied by two-dimensional column chromatography
AU - Lee, Dean
AU - Teraoka, Iwao
AU - Fujiwara, Tomoko
AU - Kimura, Yoshiharu
N1 - Funding Information:
DL and IT appreciate financial support from NSF-DMR 9975650. TF and YK acknowledge the support received through a Grant-in-Aid for Scientific Research on Priority Areas, “Sustainable Biodegradable Plastics” No. 11217210, from the Japanese Ministry of Education, Culture, Sports, Science, and Technology.
PY - 2002/8/9
Y1 - 2002/8/9
N2 - We used two-dimensional column chromatography to analyze the composition of a sample of presumably a diblock copolymer of poly(ethylene glycol) (PEG) and poly(L-lactide) synthesized from monomethoxy-terminated PEG. The first dimension of the separation is phase fluctuation chromatography to prepare fractions that contain various components of the copolymer in different ratios. The second dimension is size-exclusion chromatography, NMR, and HPLC at the critical condition of PEG. The PEG initiator has small amounts of diol-terminated dimeric components. We found that the copolymer sample contains a triblock copolymer and low-molecular-mass components in addition to the main part of the diblock copolymer. The SEC chromatograms show that the main part consists of two components with distinct peak lengths for the PLLA block. The low-molecular-mass components have a broad distribution in chemical composition. Phase fluctuation chromatography enriched the triblock copolymer and the diblock copolymer with the longer PLLA block in early fractions when the column was packed with carboxymethyl-modified porous silica. When the porous medium was PLLA-grafted silica, size exclusion dominated, but the low-molecular-mass components were separated according to their chemical composition.
AB - We used two-dimensional column chromatography to analyze the composition of a sample of presumably a diblock copolymer of poly(ethylene glycol) (PEG) and poly(L-lactide) synthesized from monomethoxy-terminated PEG. The first dimension of the separation is phase fluctuation chromatography to prepare fractions that contain various components of the copolymer in different ratios. The second dimension is size-exclusion chromatography, NMR, and HPLC at the critical condition of PEG. The PEG initiator has small amounts of diol-terminated dimeric components. We found that the copolymer sample contains a triblock copolymer and low-molecular-mass components in addition to the main part of the diblock copolymer. The SEC chromatograms show that the main part consists of two components with distinct peak lengths for the PLLA block. The low-molecular-mass components have a broad distribution in chemical composition. Phase fluctuation chromatography enriched the triblock copolymer and the diblock copolymer with the longer PLLA block in early fractions when the column was packed with carboxymethyl-modified porous silica. When the porous medium was PLLA-grafted silica, size exclusion dominated, but the low-molecular-mass components were separated according to their chemical composition.
KW - Diblock copolymer
KW - Phase fluctuation chromatography
KW - Poly(L-lactide)
KW - Poly(ethylene glycol)
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U2 - 10.1016/S0021-9673(02)00751-3
DO - 10.1016/S0021-9673(02)00751-3
M3 - Article
C2 - 12214703
AN - SCOPUS:0037047254
SN - 0021-9673
VL - 966
SP - 41
EP - 51
JO - Journal of Chromatography A
JF - Journal of Chromatography A
IS - 1-2
ER -