CO₂-Derived Methylene Oxazolidinone: A Platform Building Block for Functionalizing Ethylene–Vinyl Alcohol Copolymers

Abstract

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 of EVOHs 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 functionalizing 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.

Radical Polymerization of Methylene Heterocyclic Compounds: Functional Polymer Synthesis and Applications

“…In this respect, another CO2-sourced MHC appeared as a valuable comonomer, namely 4,4dimethyl-5-methyleneoxazolidin-2-one 34 (DMOx) (Figure 30). 116,117 The latter was produced via carboxylative cyclization of dimethylpropargylamine and copolymerized radically in a controlled manner with VAc and ethylene. Well-defined DMOx-containing PVAc 116 and EVAs 117 were prepared by OMRP and RAFT, but the latter technique appeared more suited for the production of copolymers with high DMOx content.…”

“…Various postpolymerization modifications of these MHC-based copolymers, such as hydrolysis and aminolysis reactions, gave access to unique stimuli responsive materials including pH/thermo/metal ion-responsive amino alcohol-functional poly(vinyl alcohol) as well as unprecedented pH-responsive amino-functional ethylene/vinyl alcohol (EVOHs) copolymers. 116,117 A selective post-polymerization modification of the 1,2-amino alcohol functions into oxazolidines was also reported and exploited for the preparation of EVOH gels under mild conditions. 117 116,117…”

“…116,117 A selective post-polymerization modification of the 1,2-amino alcohol functions into oxazolidines was also reported and exploited for the preparation of EVOH gels under mild conditions. 117 116,117…”

Advances in the Synthesis of Copolymers from Carbon Dioxide, Dienes, and Olefins

“…Although there is still a lack of methods for direct olefin/CO 2 copolymerization, continuous efforts have been devoted to the synthesis of copolymers from olefins and CO 2 . In this regard, copolymerization of CO 2 -based comonomers with olefins has received increasing attention. , Due to the importance of polyolefins, we believe that olefin/CO 2 copolymerization will remain a hot research topic. The key motivation for achieving this transformation is to produce sustainable polyesters that exhibit similar mechanical properties of polyolefins but are degradable because of the ester functionality located in the polymer backbone.…”

“…Synthesis of CO 2 /Ethylene/Butadiene Copolymers via EVP/Ethylene Copolymerization Scheme 6. Modification of the CO 2 /Ethylene/Butadiene Copolymers of CO 2 -based comonomers with olefins has received increasing attention 56,57. Due to the importance of polyolefins, we believe that olefin/CO 2 copolymerization will remain a hot research topic.…”