From Levulinic Acid to Imines: Creating Biobased, Recyclable, Cross-linked Rubbers through Covalent Adaptive Networks

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Materials

Background:

• Dynamic covalent bonds enable the design of recyclable materials.
• Imine chemistry is a key strategy for creating adaptive polymer networks.
• Developing sustainable and recyclable rubber-based materials is crucial.

Purpose of the Study:

• To create a fully biobased and recyclable rubber network using imine chemistry.
• To investigate the use of biobased ketones and amines as cross-linkers.
• To evaluate the recyclability and mechanical performance of the novel rubber network.

Main Methods:

• Cross-linking epoxidized natural rubber (ENR) with glycerol trilevulinate (GT) and hexamethylene diamine (HMDA).
• Characterization using mechanical tests, swelling measurements, and dielectric investigations.
• Assessing network reconstruction and performance after reprocessing.

Main Results:

• A hybrid adaptive network based on imine and hydrogen bonds was successfully formed.
• The optimal formulation (5 phr GT and 5 phr HMDA) showed improved tensile strength after recycling.
• Network integrity and mechanical properties were preserved through synergistic covalent and noncovalent interactions.

Conclusions:

• The developed biobased rubber network exhibits excellent recyclability and adaptability.
• Levulinic acid derivatives are effective for creating sustainable rubber materials.
• This approach offers a promising route for producing high-performance, eco-friendly rubber products.