Healable, Recyclable, and Mechanically Tough Polyurethane Elastomers with Exceptional Damage Tolerance

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Elastomers are crucial for industrial applications like tires and seals.
• Next-generation elastomers require a combination of healing, recycling, and damage tolerance with high mechanical properties.
• Current fabrication methods struggle to achieve these mutually exclusive properties simultaneously.

Purpose of the Study:

• To develop novel polyurethane (PU) elastomers with enhanced healability, recyclability, and mechanical toughness.
• To investigate the use of multiblock polymers and coordination chemistry for creating advanced elastomer properties.
• To overcome the limitations of current elastomers by integrating multiple desirable functionalities.

Main Methods:

• Fabrication of PU elastomers using poly(dimethylsiloxane) (PDMS)/polycaprolactone (PCL) multiblock polymers.
• Incorporation of hydrogen bonding and Zn²⁺ ion coordination motifs.
• Analysis of phase-separated dynamic hierarchical domains formed by coordinated bipyridine groups, carbamate groups, and crystallized PCL segments.

Main Results:

• The developed elastomers exhibit a tensile strength of approximately 52.4 MPa.
• Achieved high toughness (≈363.8 MJ m^-3) and exceptional fracture energy (≈192.9 kJ m^-2).
• Demonstrated convenient healing and recycling capabilities, restoring original mechanical properties and integrity upon heating.

Conclusions:

• The dynamic hierarchical domains act as effective nanofillers, enhancing mechanical strength and toughness.
• The coordination of multiblock polymers with Zn²⁺ ions successfully integrates healability, recyclability, and mechanical robustness.
• These findings pave the way for creating advanced, sustainable elastomers for demanding applications.