Controlled Polymerization of Ethyl Glyoxylate Using Alkyllithium and Alkoxide Initiators

The synthesis of poly(ethyl glyoxylate)s (PEtGs) by anionic polymerization was explored. PEtGs are a subclass of stimulus-responsive self-immolative polymers with promising properties for applications as coatings, sensors, and drug delivery vehicles. In this paper, a new purification procedure for the preparation of highly pure ethyl glyoxylate (EtG), suitable for anionic polymerization reactions, and the first successful examples of controlled polymerization of EtG are described. n-BuLi, PhLi, and t-BuLi were employed as initiators under different experimental conditions, and their behavior was examined using NMR spectroscopy, size exclusion chromatography, and thermal analysis to develop an optimized procedure. As functional alkoxide initiators, propargyl alkoxide was employed in optimization studies and poly(ethylene glycol) (PEG) dialkoxide was utilized for the direct synthesis of PEtG-PEG-PEtG copolymers. The new polymerization method revealed many features of controlled polymerization reactions, yielding PEtGs with predictable molar masses and relatively low dispersity values.