Controlled “one-pot” block copolymerization of β-butyrolactone and oxiranes via quantitative active centers transformation

Abstract

The synthesis of block copolymers of oxiranes and β-butyrolactone based on a method of sequential monomer addition was developed. The anionic controlled polymerization of protected glycidol - ethoxyethyl glycidyl ether (EEGE) and β-butyrolactone (BBL) was used. By quantitatively transforming the hydroxyl groups at the ends of the polyoxirane chains to the carboxylate centers, a one-pot synthesis was possible without further purification of the intermediates. The main part of the study was directed toward verifying the degree of precision of the transformation step and copolymer synthesis and clarifying the role of hydroxyl groups potentially present during the polymerization of BBL. It was also found that the presence of a small excess of anhydride during the transformation reaction did not affect the subsequent synthesis steps. The use of a macroinitiator in the form of poly(ethylene glycol) allowed us to obtain well-defined block copolymers of oxiranes and BBL of di-, tri- and pentablock structures.