Reprocessability in Engineering Thermosets Achieved Through Frontal Ring-Opening Metathesis Polymerization.

While valued for their durability and exceptional performance, crosslinked thermosets are challenging to recycle and reuse. Here, inherent reprocessability in industrially relevant polyolefin thermosets is unveiled. Unlike prior methods, this approach eliminates the need to introduce exchangeable functionality to regenerate the material, relying instead on preserving the activity of the metathesis catalyst employed in the curing reaction. Frontal ring-opening metathesis polymerization (FROMP) proves critical to preserving this activity. Conditions controlling catalytic viability are explored to successfully reclaim performance across multiple generations of material, thus demonstrating long-term reprocessability. This straightforward and scalable remolding strategy is poised for widespread adoption. Given the anticipated growth in polyolefin thermosets, these findings represent an important conceptual advance in the pursuit of a fully circular lifecycle for thermoset polymers.