Re-Assemblable, Recyclable, and Self-Healing Epoxy Resin Adhesive Based on Dynamic Boronic Esters

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Chemistry

Background:

• Thermosetting adhesives, while widely used, are difficult to re-process due to permanent covalent cross-links.
• Current adhesive production relies heavily on non-renewable petroleum resources, posing environmental and sustainability challenges.

Purpose of the Study:

• To develop a recyclable and sustainable thermosetting adhesive.
• To incorporate dynamic covalent chemistry into bio-based epoxy resins for re-processability.

Main Methods:

• Synthesis of epoxidized soybean oil and dynamic boronic esters.
• Characterization using proton nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC).
• Evaluation of network properties via swelling tests and tensile measurements, alongside self-healing and reprocessing experiments.

Main Results:

• Successful synthesis and characterization of the bio-based epoxy resin and boronic esters.
• Confirmation of covalently cross-linked networks within the adhesive material.
• Demonstration of self-healing capabilities and successful reprocessing under mild conditions.

Conclusions:

• A novel, recyclable thermosetting adhesive was successfully developed using soybean oil-derived epoxy resin and dynamic boronic esters.
• The dynamic nature of the boronic ester linkages allows for network re-assembly, enabling self-healing and reprocessing.
• This work presents a sustainable alternative to petroleum-based adhesives with enhanced re-processability.