CO2-Derived methylene oxazolidinone: a platform building block for functionalizing ethylene–vinyl alcohol copolymers

Ethylene−vinyl alcohol copolymers (EVOHs) are important materials available in a variety of compositions and valued in countless applications. In spite of their great adaptability offered by the adjustment of their ethylene content, the chemical modification ofEVOHs is often considered to tune their properties and functionalities in order to meet the stringent requirements of today’s applications. While post-polymerization modification of the pendant hydroxyl groups of EVOHs is the prevailing functionaliz- ing strategy, this multistep approach consumes part of the alcohols of EVOHs and remains limited in terms of functions. This work reports a straightforward platform for the synthesis of functional EVOHs, in particular, amino derivatives, involving a CO2-derived oxazolidinone-containing methylene heterocycle, namely, 4,4-dimethyl-5-methyleneoxazolidin-2-one (DMOx). The ethylene/ DMOx and ethylene/vinyl acetate/DMOx copolymerizations were implemented by conventional and reversible deactivation radical copolymerization. The resulting oxazolidinone-containing ethylene-based copolymers were then converted into novel vicinal amino alcohol-functional EVOHs via hydrolysis of esters and oxazolidinones. A selective post-modification method of these 1,2-amino alcohol-functional EVOHs into their oxazolidine counterparts is also reported. Finally, the peculiar thermal and solution properties, including pH-responsiveness, of these novel vicinal amino alcohol- and oxazolidine-functional EVOHs as well as oxazolidinone EVAs are discussed.