Covalent Adaptable Networks with Tailorable Material Properties Based on Divanillin Polyimines.

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Chemistry

Background:

• Thermosets offer high mechanical and chemical robustness but are not reprocessable.
• Covalent adaptable networks (CANs) aim to combine thermoset properties with reprocessing capabilities.
• Developing sustainable alternatives to fossil-based thermosets is crucial.

Purpose of the Study:

• To design and synthesize novel polyimine-based covalent adaptable networks (CANs) with high renewable content.
• To investigate the structure-property relationships and tailor the thermomechanical performance of these CANs.
• To evaluate the reprocessing and chemical recycling potential of the developed CANs.

Main Methods:

• Synthesis of polyimine-based CANs using divanillin derivatives and aliphatic fatty acid-based amines.
• Characterization of thermomechanical properties including tensile strength and glass transition temperature.
• Assessment of reprocessing cycles and chemical recycling via monomer recovery.

Main Results:

• CANs with varying ratios of flexible and rigid amines exhibited tunable tensile strength (1.07-18.7 MPa) and glass transition temperatures (16-61 °C).
• The synthesized CANs demonstrated fast stress relaxation due to reversible imine functionality.
• Materials were successfully reprocessed up to three times without significant performance loss and chemically recycled to recover the divanillin monomer.

Conclusions:

• Polyimine-based CANs with high renewable content offer a promising, sustainable alternative to conventional thermosets.
• The ability to reprocess and chemically recycle these materials addresses end-of-life concerns for polymers.
• These adaptable networks pave the way for environmentally friendly materials with tunable properties.