Reprocessible Triketoenamine-Based Vitrimers with Closed-Loop Recyclability.

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Chemistry

Background:

• Thermosets are widely used but difficult to recycle, posing environmental challenges.
• Developing recyclable thermosets via chemical and thermo-mechanical methods is crucial for sustainability.

Purpose of the Study:

• To design and synthesize a novel dynamic covalent network based on triketoenamine for recyclable thermosets.
• To investigate the recyclability, mechanical properties, and adaptability of the developed polymer network.

Main Methods:

• Synthesis of a triketoenamine-based dynamic covalent network from 2,4,6-triformylphloroglucinol and secondary amines.
• Characterization of the network's dynamic features, mechanical properties (tensile strength, Young's modulus), and recyclability.
• Evaluation of the material's ability to form a catalyst-free, low-temperature reprogrammable covalent adaptable network (vitrimer).

Main Results:

• The triketoenamine network exhibits dynamic covalent bonding due to reduced intramolecular hydrogen bonding and tautomer stability.
• The polymer shows high mechanical properties (79.4 MPa tensile strength, 571.4 MPa Young's modulus).
• Achieved up to 90% monomer yield recycling via an aqueous solution, restoring original material strength; developed a catalyst-free vitrimer.

Conclusions:

• A novel, highly recyclable thermoset was developed using a triketoenamine dynamic covalent network.
• The material demonstrates excellent mechanical performance and recyclability, enabling monomer-network-monomer transformation.
• The design approach offers a pathway for creating sustainable polymers and vitrimers with enhanced repressibility and recyclability.