From the Design of Novel Tri- and Tetra-Epoxidized Ionic Liquid Monomers to the End-of-Life of Multifunctional Degradable Epoxy Thermosets
Résumé
The design and development of multifunctional
epoxy thermosets have recently stimulated continuous research on
new degradable epoxy monomers. Herein, tri- and tetra-epoxidized
imidazolium monomers were rationally designed with cleavable
ester groups and synthesized on a multigram scale (up to 100 g),
yielding room-temperature ionic liquids. These monomers were
used as molecular building blocks and cured with three primary
amine hardeners having different reactivities, leading to six different
network architectures. Overall, the resulting epoxy−amine networks
exhibit high thermal stability (>350 °C), excellent
mechanical properties combined with a shape memory behavior,
glass transition temperatures (Tgs) from 55 to 120 °C, and
complete degradability under mild conditions. In addition,
nonpolarizable, all-atom molecular dynamics simulations were applied in order to investigate the molecular interactions during
the polyaddition reaction-based polymerization and then to predict the thermomechanical and mechanical properties of the resulting
networks. Thus, this work employs computational chemistry, organic synthesis, and material science to develop high-performance as
well as environmentally friendly networks to meet the requirements of the circular economy.