POLYMERIZATION OF LACTONES .17. SYNTHESIS OF ETHYLENE GLYCOL-L-LACTIDE BLOCK-COPOLYMERS

The anionic polymerization of L-lactide in the presence of the sodium poly(ethylene glycol)ate in tetrahydrofuran at 25-degrees-C yields ''t ailored'' ABA triblock copolymers having the expected compositions and molecular weights. During the polymerization, a slight racemization o f L-lactide was observed. The water absorption experiments indicate th at the introduction of the poly(ethylene glycol) block into the L-lact ide polymer chain markedly increases its hydrophilicity. It was reveal ed that the morphology and mechanical properties of block copolymers d epend strongly on their composition and thermal treatment.