Lignin-containing polyurethane elastomers with enhanced mechanical properties via hydrogen bond interactions

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Materials

Background:

• Polyurethane elastomers (PUE) are versatile polymers with applications in various industries.
• Lignin, a byproduct of the paper and biofuel industries, is an abundant and renewable aromatic polymer.
• Developing sustainable alternatives to petroleum-based materials is crucial for environmental protection.

Purpose of the Study:

• To synthesize lignin-based polyurethane elastomers (LPUE) using lignin as a reactive raw material.
• To investigate the effects of lignin on the structure, thermal stability, mechanical performance, and self-healing properties of polyurethane elastomers.
• To explore the potential of lignin as a sustainable component in high-performance elastomers.

Main Methods:

• Synthesis of lignin-containing polyester polyol (LPES) via vacuum melting.
• Reaction of LPES with isocyanate and chain extender to form LPUE.
• Systematic study of the influence of lignin's role (reactive raw material, chain extender, filler) on material properties.
• Characterization of structural, thermal, mechanical, and self-healing properties.

Main Results:

• Successful synthesis of LPUE with enhanced comprehensive mechanical properties.
• Maximum tensile strength increased to 26.6 MPa and elongation at break reached 408.6%.
• Lignin incorporation significantly improved thermal stability and mechanical performance, with distinct effects depending on its location (hard vs. soft segment).
• Formation of a microphase-ordered structure due to hydrogen bonding interactions of lignin's polar groups.

Conclusions:

• Lignin can be effectively utilized as a reactive raw material to produce high-performance polyurethane elastomers.
• The incorporation of lignin leads to substantial improvements in mechanical strength, thermal stability, and potentially self-healing properties.
• LPUE offers a sustainable and promising alternative to conventional polyurethane elastomers, leveraging an abundant bio-based resource.