Toward versatile biobased epoxy vitrimers by introducing aromatic N-heterocycles with stiff and flexible segments

Recyclable materials with simultaneous multifunctionality and high performance, especially polymers synthe-sized from biobased monomers, have recently attracted a great deal of interest. However, current traditional vitrimers exhibit trade-offs between high performance and reprocessing. To circumvent this inherent contra-diction, we report the first attempt to introduce an aromatic N-heterocycles (the fixed 'stiff' segments) derived from biomass functionalized with ester groups (the dynamic 'flexible' segments) into a thermoset system. The resulting resins exhibited high flexural strength (151 MPa) and toughnesses, a high glass transition temperature (205 celcius), intrinsic flame retardancy (UL-94 V-0) and acid/base resistance. In addition, the ester groups and aromatic N-heterocycles enabled dissolution of the network in ethylene glycol without additional catalyst. Importantly, the degradation solution could be directly reused into high-value photothermal conversion coatings and adhesives with 100% recyclability just by evaporating the ethylene glycol at elevated temperatures. Addi-tionally, the conjugated aromatic N-heterocycles enhanced the adhesive properties and photothermal conversion of the system. The ease with which biobased materials bearing N-heterocycles and ester groups can be synthe-sized, recycled, and reused without losing value provides a new direction for closed-loop, high-performance and versatile polymer life cycles.

Automated summary

Recyclable materials, particularly polymers synthesized from biobased monomers, have gained significant attention due to their multifunctionality and high performance. In order to overcome the trade-off between high performance and reprocessing in traditional materials, an aromatic N-heterocycles derived from biomass functionalized with ester groups were introduced into a thermoset system. The resulting resins showed exceptional flexural strength, high glass transition temperature, flame retardancy, and acid/base resistance. Additionally, the ester groups and aromatic N-heterocycles enabled easy dissolution of the network in ethylene glycol without additional catalyst. The ability to synthesize, recycle, and reuse biobased materials bearing N-heterocycles and ester groups without losing value opens up new possibilities for closed-loop, high-performance, and versatile polymer life cycles.