Harnessing Cyclopentadiene-Maleimide Chemistry and Cyclic Polymer Networks for Stimuli-Responsive and Adaptable Thermosets

The development of high-performance thermoset materials is essential for applications requiring superior mechanical strength, chemical resistance, and thermal stability, such as in the aerospace and automotive industries. This work leverages cyclopentadiene (Cp)-maleimide chemistry, a powerful approach for synthesizing well-defined polymer networks, to investigate how crosslinked topology affects material properties. To manage the high reactivity of Cp, we employ norbornadiene (NBD) as a masked Cp unit, which is deprotected via an inverse electron-demand Diels–Alder (IEDDA) reaction, allowing for the efficient synthesis of pure Cp monomers. Our research focuses on integrating Cp-Maleimide crosslinking with cyclic polymer structures, creating a unique network featuring macrocyclic loops within the thermoset material. By further incorporating reversible disulfide bonds, we aim to establish a dual covalent network capable of redox-induced transformations between rigid and flexible states, providing tunability in mechanical performance. In this work, we will describe the differences in properties such as elastic modulus and toughness between cyclic and linear analogues, as well as the synthetic preparation of these materials. We believe this novel approach opens new possibilities for controlling material rigidity and adaptability through reversible network disruptions, laying the foundation for stimuli-responsive thermosets.