Synthesis and Characterization of Block Copolymers of <i>ε</i>‐Caprolactone and <scp>DL</scp>‐Lactide Initiated by Ethylene Glycol or Poly(ethylene glycol)

Abstract

Abstract Biodegradable copolymers were prepared by ring‐opening polymerization of sequentially added ε ‐caprolactone and DL ‐lactide in the presence of ethylene glycol or poly(ethylene glycol), using zinc metal as catalyst. Polymerization was performed in bulk and yielded block copolymers with predetermined PEG/PCL/PLA segments. The obtained polymers were characterized by 1 H NMR, SEC, IR, DSC, TGA, and X‐ray diffraction. Data showed that the copolymers preserved the excellent thermal behavior inherent to PCL. The crystallinity of PLA‐containing copolymers was reduced with respect to PCL homopolymer. The presence of both hydrophilic PEG and fast degrading PLA blocks should improve the biocompatibility and biodegradability of the materials, which are of interest for applications as substrate in drug delivery or as scaffolding in tissue engineering. Block copolymerization of ε ‐caprolactone and DL ‐lactide initiated by dihydroxyl PEG. magnified image Block copolymerization of ε ‐caprolactone and DL ‐lactide initiated by dihydroxyl PEG.