27 Mai 2019

Researchers develop biobased, self-healing elastomer derived from lignin

To achieve these results, ORNL researchers developed a unique method to extract a specific form of lignin

Scientists at Oak Ridge National Laboratory (ORNL) have developed a new, stretchy, plant-derived material that outperforms the adhesiveness of the natural chemical that gives mussels the ability to stick to rocks and ships.

This bio-based material—composed of lignin (the substance that gives plants sturdiness) and epoxy—can self-heal and elongate up to 2,000%. Converting lignin into well- defined compounds is often challenged by structural complexation and inorganic contamination induced by the pulping process.

To achieve these results, researchers developed a unique method to extract a specific form of lignin. Instead of breaking down lignin into small molecules, we extracted a uniform and rigid oligomer from the lignin waste stream. The multifunctional polyphenol oligomer containing carboxylic acid, alcohol, and phenol groups is highly reactive and brings stiffness into the material matrix.

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Researchers developed a new material using epoxy mixed with a form of lignin naturally rich in hydroxyl groups that can self-heal if sliced and elongate up to 2,000%. Photo courtesy of ORNL

 

The resulting molecular structure creates a super-sticky, Tough, super-sticky elastomers are economically prepared from this oligomer by a reaction with epoxy-terminated polyethylene glycol, without needing any solvent. The highly elastic material can heal quickly, where broken, through hydrogen bonding

This extracted lignin shows promise for a range of industrial applications including coatings, glues, and hydrogels. The results, published in ACS Macro Letters, demonstrate new potential for a small, but high-value portion of the lignin waste stream from biorefineries and the pulp and paper industry.

Source: Bioplastics MAGAZINE, 2019-05-21.

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