ICCAS OpenIR
Synthesis and characterization of biocompatible triblock copolymers poly(2-ethyl-2-oxazoline)-b-poly(epsilon-caprolactone)-b-poly (L-glutamic acid) with thermal- and pH-sensitivities
Wang Huanbing1; Chen Xuesi2; Pan Caiyuan1
2008-02-01
Source PublicationACTA POLYMERICA SINICA
ISSN1000-3304
Issue2Pages:161-167
AbstractTriblock copolymers, poly ( 2-ethyl-2-oxazoline)-b-poly (epsilon-caprolactone)-b-poly ( L-glutamic acid) (PEOz-b-PCL-b-PLGlu)s with thermo- sensitive PEOz and pH-sensitive PLGlu have been successfully synthesized. Synthetic procedure includes the following Steps. (1) PEOz capped with hydroxyl groups was prepared by ring-opening polymerization of 2-ethyl-2-oxazoline using methyl-p-toluenesulfonate as initiator, and following transformation of terminal cationic ions into hydroxyl groups in the presence of KOH. The molecular weights of the resultant polymers increased with increasing the molar ratio of monomer to initiator. (2) The block copolymers, PEOz-b-PCL were synthesized by ring-opening polymerization of E-caprolactone using PEOz-OH as macroinitiator and Sn(Oct), as catalyst. Their structure was confirmed by their H-1-NMR and FT-IR spectra. In comparison with FT-IR spectrum of its precursor PEOZ, a new absorption band at u = 1734 cm(-1) was observed, and the characteristic signals of PEOz and PCL could be found in the H-1-NMR spectra, delta = 3.47,2.21 similar to 2.56 and 1. 14 for PEOz, 8 = 4.12,2.35, 1.68 and 1.43 for PCL. The relative amount of the two monomer units in the resultant copolymers is determined by their molar ratio in the feed. Their Mn (NMR) agrees well with the theoretical number-average molecular weight, and their molecular weight distribution is relatively narrow. (3) For application of PEOz-b-PCL-OH as macroinitiator in the ring-opening polymerization of N-carboxyl anhydride of gamma-benzyl-L-glutamate (BLG-NCA), it is necessary to convert the terminal hydroxyl group into primary amine. This transformation was achieved by condensation reaction of PEOz-b-PCL-OH with Phe-(BOC)-B-N in the presence of DCC,and successively the protective group BOC was removed to produce amine -terminated copolymer after treated with TFA. Based on the integration ratio of ester methylene protons in PCL to the new signal at 6 = 7.38 corresponding to phenyl protons in the terminal phenylalanine group, we can estimated that this reaction efficiency was very high. (4) The triblcok copolymer, PEOz-b-PCL-b-PBLG was obtained by ring-opening polymerization of BLG-NCA derived from benzyl glutamate using PEOz- b -PCL-NH2, as macroinitiator, and the polymerization was carried out in CH, Cl at 30 degrees C for 72 h. Its FT-IR spectrum showed the absorption bands of NH and benzene ring at u = 3292, 697 and 749 cm(-1), indicating the occurrence of the block copolymerization. The structure of the resultant triblock copolymer was further verified by its H-1-NMR spectrum, the characteristic signals of PEOz, PCL and PBLG appeared at 8 = 3.47 (-NHCH2 in PEO2.),4.12 D (COOCH2,F in PCL) and 5.07 D (PhCH2,F in PBLG) respectively. Based on their integration ratio, their relative amount in the copolymer can be calculated. (5) The protective benzyl groups in PEOz-b-PCL-b-PBLG was removed and the target triblock copolymer, PEOz-b-PCL-b-PLGlu was obtained after treated with HBr. Complete disappearance of benzyl signals at 8 = 5.07 and 7.28 in their H-1-NMR spectra indicates the complete removal of benzyl groups.
KeywordBlock Copolymer Peoz Plglu Pcl Temperature-sensitivity Ph-sensitivity
Indexed BySCI
Language英语
WOS IDWOS:000254640200011
PublisherSCIENCE CHINA PRESS
Citation statistics
Cited Times:4[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.iccas.ac.cn/handle/121111/64794
Collection中国科学院化学研究所
Corresponding AuthorWang Huanbing
Affiliation1.Univ Sci & Technol China, Dept Polymer Sci & Engn, Hefei 230026, Peoples R China
2.Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Peoples R China
Recommended Citation
GB/T 7714
Wang Huanbing,Chen Xuesi,Pan Caiyuan. Synthesis and characterization of biocompatible triblock copolymers poly(2-ethyl-2-oxazoline)-b-poly(epsilon-caprolactone)-b-poly (L-glutamic acid) with thermal- and pH-sensitivities[J]. ACTA POLYMERICA SINICA,2008(2):161-167.
APA Wang Huanbing,Chen Xuesi,&Pan Caiyuan.(2008).Synthesis and characterization of biocompatible triblock copolymers poly(2-ethyl-2-oxazoline)-b-poly(epsilon-caprolactone)-b-poly (L-glutamic acid) with thermal- and pH-sensitivities.ACTA POLYMERICA SINICA(2),161-167.
MLA Wang Huanbing,et al."Synthesis and characterization of biocompatible triblock copolymers poly(2-ethyl-2-oxazoline)-b-poly(epsilon-caprolactone)-b-poly (L-glutamic acid) with thermal- and pH-sensitivities".ACTA POLYMERICA SINICA .2(2008):161-167.
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