Combination of Fluorine and Tertiary Amine Activation in Catalyst-Free Thia-Michael Covalent Adaptable Networks

A series of catalyst-free covalent adaptable networks (CANs) have been developed using a reversible thia-Michael reaction activated by fluorine atom substitution and by an intramolecular tertiary amine. The thia-Michael exchange rate was first evaluated by a preliminary molecular study coupled to density functional theory (DFT) calculations. This study enabled us to highlight the necessity of combining fluorine and tertiary amine activation to observe the thia-Michael exchange. Then, by modulating the structure, nature, and functionality of the thiol monomers, a wide range of mechanical properties and thermal properties were achieved. Relationships between the monomer structure and the dynamic properties were also highlighted through the dynamic study of these materials. Finally, the ability of the fluorinated thia-Michael CANs to be reprocessed was assessed by thermal and mechanical analyses of up to three reshaping cycles.