Dual Dynamic Chemistries Enable Tough and Degradable Bio‐Based Vitrimers

The pursuit of high‐performance thermosets and carbon fiber reinforced polymers (CFRPs) with enhanced sustainability is hampered by a tradeoff: performance or recyclability. Here we explore a novel bio‐based formulation utilizing disulfide and silyl ether chemistries (DVSS 50 SiO 50 ) alongside the mono‐dynamic resins. Carbon fiber recovery is shown in the case of the dual‐dynamic resin (some residue) and the pure silyl ether resin (complete) under chemoselective recycling conditions, confirming the potential for Si─O bonds to enable facile degradability. Incorporation of disulfide linkages via an aniline‐based aryl disulfide monomer enhances stress relaxation, unlocking faster reformability without sacrificing structural integrity. Mechanical reprocessing of the resins yielded materials with similar stiffness but a slight decrease in the T g of the resins. High K Q fracture toughness values were observed, driven by the vanillyl alcohol‐derived epoxy monomer and proposed mechanochemical activation of dynamic bonds at the crack tip. This initial investigation shows that a combination of dynamic and selectively cleavable chemistries could enable high‐performance thermosets with reformability, mechanical recyclability, and mild chemical degradation for fiber recovery. Additionally, the tradeoff between enhanced chemical degradability and stress relaxation arising from Si─O and S─S bonds is shown.