Closed‐Loop Recycling of Covalent Adaptable Network (<scp>CAN</scp>) Derived From Dopamine and Waste <scp>PET</scp>

ABSTRACT Covalent adaptable networks (CANs) have established a unique paradigm for developing recyclable thermosets. However, the majority of the CANs are derived from non‐renewable resources. Incorporating bio‐based feedstock in the design of CANs would further enhance sustainability. To this end, this work introduces a strategy to construct a CAN from bio‐based dopamine and plastic (PET) waste. The pursuit of novel molecules for the derivation of CAN motivated us to introduce dopamine in this report. The dopamine was transformed into a tetra‐functional alcohol monomer, which resulted in CAN upon polymerization with pyromellitic dianhydride. The CAN exhibited appreciable thermal stability, noteworthy mechanical properties, and excellent chemical and solvent resistance. The catalyst‐free reprocessing of the CAN was demonstrated. The viscoelastic behavior of the CAN was examined using rheological measurements. Finally, toward achieving the closed‐loop circular economy, the CAN was chemically degraded, and the monomer was recovered in high yield (91%) and purity, allowing the remaking of CAN. Our exploration expands the scope of diverse bio‐derived feedstock toward the synthesis of CANs. To the best of our knowledge, this is the first report that describes the derivation of reprocessable thermoset‐like CAN from dopamine and waste plastic and their subsequent chemical recycling.