Fractionation of Lignin for Selective Shape Memory Effects at Elevated Temperatures

Area of Science:

• Polymer Science
• Materials Science
• Biomass Valorization

Background:

• Lignin, a byproduct of biorefineries, offers potential for sustainable polymer development.
• Controlling the thermomechanical properties and shape memory effects of lignin-based polymers remains challenging.
• Existing methods often lack the precision to tailor lignin for specific high-performance applications.

Purpose of the Study:

• To develop a facile approach for controlling shape memory effects in lignin-based multiphase polymers.
• To investigate the correlation between fractionated lignin structures and thermomechanical characteristics.
• To enhance the application window of lignin-based materials through precise property tuning.

Main Methods:

• Solvent fractionation of syringylpropane-rich technical organosolv lignin.
• Melt-phase reaction of fractionated lignins with acrylonitrile butadiene rubber (NBR).
• Characterization using electron microscopy, melt-rheology, dynamic mechanical analysis, and ultra-small angle neutron scattering.

Main Results:

• Selective lignin structures with excellent thermal stability, high stiffness, and melt-flow resistance were obtained.
• Partially networked NBR-lignin elastomers exhibited programmable shape memory at 70 °C and 150 °C.
• Materials demonstrated tunable shape fixity, high strain/stress recovery, and superior stress tolerance.

Conclusions:

• Solvent fractionation of lignin enables enrichment of specific properties for efficient shape memory effects.
• The developed elastomers offer a versatile platform for advanced material applications requiring programmable shape changes.
• This method broadens the application scope of lignin-based polymers, promoting sustainable material innovation.