A Fully Bio-Based Elastomer with Ultrahigh Lignin Content and Performance Rivaling Nitrile Rubber

Area of Science:

• Materials Science
• Green Chemistry
• Polymer Science

Background:

• Renewable, high-performance elastomers are crucial for sustainable materials.
• Industrial Kraft lignin is an abundant, underutilized lignocellulosic byproduct.
• Developing eco-friendly alternatives to petroleum-based elastomers is a key scientific goal.

Purpose of the Study:

• To create a high-performance, recyclable elastomer directly from industrial Kraft lignin.
• To investigate a one-pot in situ graft copolymerization strategy for lignin valorization.
• To evaluate the properties and recyclability of the resulting lignin-based elastomer.

Main Methods:

• Utilized a deep eutectic solvent (oxalic acid and 1,6-hexanediol) for lignin dissolution and graft copolymerization.
• Employed a catalyst-free esterification process at 110°C to form an interpenetrating rigid-flexible network.
• Incorporated 50-75 wt.% lignin into the elastomer structure.

Main Results:

• The optimal elastomer achieved a tensile strength of 12.0 MPa, 878% elongation, and 85.1 MJ m⁻³ fracture energy.
• Properties rivaled or exceeded those of petroleum-derived nitrile butadiene rubber.
• Demonstrated excellent oil and abrasion resistance, electrical insulation, photothermal conversion, and infrared-induced self-healing.
• The material exhibited efficient closed-loop recyclability through reprocessing.

Conclusions:

• A scalable route to high-performance, recyclable elastomers from abundant lignin byproduct was established.
• This lignin-based elastomer presents a sustainable alternative to conventional synthetic rubbers.
• The developed material holds significant potential for broad applications in eco-friendly materials.