Lactone End-Capped Poly(ethylene oxide) as a New Building Block for Biomaterials

Abstract

This paper reports on the synthesis of a novel poly(ethylene oxide) (PEO) macromonomer, which can be copolymerized with ε-caprolactone (ε-CL) by ring-opening polymerization (ROP). PEO chains end-capped by an ε-caprolactone unit (γPEO·CL) have been synthesized by living anionic ring-opening polymerization of ethylene oxide (EO) initiated by the potassium alkoxide of 1,4-dioxaspiro[4.5]decan-8-ol, followed by derivatization of the acetal into a ketone and the Baeyer−Villiger oxidation of the ketone into a lactone. The end-capping of PEO by ε-CL was assessed by FTIR, MALDI−TOF, and 1H NMR spectroscopy.This type of macromonomer is a precursor of amphiphilic comblike copolymers consisting of a biodegradable hydrophobic backbone of poly-(ε-caprolactone) (PCL) and hydrophilic PEO grafts. Copolymerization of γPEO·CL with ε-CL was successfully initiated by aluminum alkoxide.