Multi-Generation Recycling of Thermosets Enabled by Fragment Reactivation

• DOI: 10.1021/jacs.4c17395
• Publication Date: 2025-04-04T05:39:52Z
• Authors: Kwangwook Ko; Edgar B. Mejia; Hayden E. Fowler; Suong T. Nguyen; Yasmeen AlFaraj; Yuyan Wang; Samuel C. Leguizamon; Nancy R. Sottos; Jeremiah A. Johnson
• Keywords: Fragment (logic); Thermosetting polymer

Thermosets are used in numerous industrial applications due to their excellent stabilities and mechanical properties; however, covalently cross-linked structures limit chemical circularity. Cleavable comonomers (CCs) offer a practical strategy impart new end-of-life opportunities, such as deconstructability or remoldability, thermosets without altering critical properties, cost, manufacturing workflows. Nevertheless, CC-enabled recycling of has so far been limited one cycle with 25% recycled content. Here, we introduce "fragment reactivation" strategy, wherein the oligomeric fragments obtained from thermoset deconstruction activated functional groups that improve fragment solubility reactivity for subsequent rounds recycling. Using polydicyclopentadiene (pDCPD), an hydrocarbon material, containing low loadings siloxane-based CC, first demonstrate two by incorporating 40 wt % norbornene silyl ether-reactivated derived prior generation's deconstruction. Then, show two-step sequence reactivation can be unified into single-step process, referred "deconstructive reactivation." this approach, three 40-45 incorporated per while maintaining key material properties deconstructability. These generations effectively extend lifespan deconstructable pDCPD ∼2.6 times. Combined CCs, presents promising potentially generalizable efficiency thermosets.