Synthesis of three-armed poly(trans-4-hydroxy-N-benzyloxycarbonyl-L- proline)-block-poly(ε-caprolactone) copolymers

Ren Shen Lee*, Jen Ming Yang

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

5 Scopus citations


A series of novel types of three-armed poly(trans-4-hydroxy-N- benzyloxycarbonyl-L-proline)-block-poly(ε-caprolactone) (PHpr-b-PCL) copolymers were successfully synthesized via melt block copolymerization of trans-4-hydroxy-N-benzyloxycarbonyl-L-proline (N-CBz-Hpr) and ε-caprolactone (ε-CL) with a trifunctional initiator trimethylolpropane (TMP) and stannous octoate (SnOct2) as a catalyst. For the homopolycondensation of N-CBz-Hpr with TMP initiator and SnOct 2 catalyst, the number-average molecular weight (Mn) of prepolymer increases from 530 to 3540 g mol-1 with the molar ratio of monomer to initiator (3-30), and the molecular weight distribution (M w/Mn) is between 1.25 to 1.32. These three-armed prepolymer PHpr were subsequently block copolymerized with ε-caprolactone (ε-CL) in the presence of SnOct2 as a catalyst. The M n of the copolymer increased from 2240 to 18,840 g mol-1 with the molar ratio (0-60) of ε-CL to PHpr. These products were characterized by differential scanning calorimetry (DSC), 1H NMR, and gel permeation chromatography. According to DSC, the glass-transition temperature (Tg) of the three-armed polymers depended on the molar ratio of monomer/initiator that were added. In vitro degradation of these copolymers was evaluated from weight-loss measurements and the change of M n and Mw/Mn.

Original languageEnglish
Pages (from-to)1708-1717
Number of pages10
JournalJournal of Polymer Science, Part A: Polymer Chemistry
Issue number8
StatePublished - 15 04 2005
Externally publishedYes


  • Degradation
  • Three-armed block copolymer
  • Trifunctional initiator


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