Benzyl β-malolactonate: synthesis, copolymerization and design of novel biodegradable macromolecular surfactants

Olivier Coulembier,Philippe Degée,Philippe Dubois,Jessica Ghisdal,Girolamo Cirrincione

doi:10.3998/ark.5550190.0008.a07

Abstract

Racemic [R,S] benzyl β-malolactonate monomer (MLABz) was synthesized according to the well-established “aspartic acid” route and purified to such an extend that it allowed the controlled synthesis of poly([R,S] β-malic acid)-b-poly((D,L)-lactide) diblock copolymers by a versatile three-step pathway combining anionic and coordination-insertion ROP of MLABz and lactide monomers, respectively. For the sake of comparison, amphiphilic poly([R,S] β-malic acid)-b-poly(e-caprolactone) diblock copolymers of identical composition were synthesized as well. The associating behavior of monodisperse diblock copolymers consisting of water-soluble poly(β-malic acid) block and hydrophobic polylactide or poly(e-caprolactone) block was studied in aqueous solution. Accordingly, both types of copolymers were dissolved directly in water and (dynamic) surface tension measurements were carried out. It came out that poly(β-malic acid)-bpoly((D,L)-lactide) amphiphilic diblock copolymers showed tensioactive properties with a lower critical micellar concentration, a higher efficiency of adsorption and a better monomer coefficient diffusion compared to corresponding poly(β-malic acid)-b-poly(e-caprolactone) diblock copolymers of comparative composition.

Highlights

The controlled synthesis and thorough characterization of well-definedmolecular structures is prerequisite to the development of new polymeric materials with tunable properties, whatever the application
Material properties that can only be reached by controlling the polymerization and macromolecular parameters. The synthesis of such diblock copolymers can be achieved by sequential addition of hydrophobic and hydrophilic monomers starting from an asymmetric difunctional initiator
This paper aims at reporting on the synthesis procedure for producing well-defined biodegradable and biocompatible poly(β-malic acid)-b-polylactide diblock copolymers (PMLAb-PLA) with controlled composition and molecular weight

Summary

Introduction

The controlled synthesis and thorough characterization of well-defined (macro)molecular structures is prerequisite to the development of new polymeric materials with tunable properties, whatever the application. After a given reaction time, the diethylaluminum alkoxide growing species have been selectively deactivated by the addition of a few drops of a HCl aqueous solution (0.1 mol.L-1), and the poly(benzyl β-malolactonate)-b-poly((D,L)-lactide) diblock copolymers (PMLABz-b-PLA) have been recovered by precipitation from cold methanol.

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Conclusion