Abstract: L-Lactide/ε-caprolactone copolymers with varying compositions and molecular weight were synthesized via ring-opening polymerization using Sn(Ⅱ)octoate as a catalyst and ethylene glycol as an initiator. The structure of the copolymers was characterized using Fourier transform infrared spectrometer, nuclear magnetic resonance spectra, and gel permeation chromatography, the thermal properties using differential scanning calorimeter, and the hydrophilicity using contact angle. Changing the monomer molar ratios and using ethylene glycol as an initiator in feed could adjust the chemical compositions，molecular weight and thermal properties of the copolymers, however, had little effect on the hydrophilicity.

Key words: L-lactide, ε-caprolactone, ring-opening polymerization, copolymer, property