Thermoset Shape-Memory Polyurethane with Intrinsic Plasticity Enabled by Transcarbamoylation

Area of Science:

• Polymer Science
• Materials Science
• Chemical Engineering

Background:

• Thermoset polymers possess excellent thermomechanical properties but are generally intractable due to chemical crosslinking.
• Shape-memory polymers (SMPs) typically differ between thermoset and thermoplastic types, with thermosets offering robust shape memory but lacking permanent shape redefinition.
• Classical thermoset shape-memory polyurethanes are known for their inability to be permanently reshaped.

Purpose of the Study:

• To investigate the potential for permanent reshaping in classical thermoset shape-memory polyurethanes.
• To explore the underlying mechanism enabling plasticity in these intractable materials.
• To demonstrate novel shape-shifting capabilities in thermoset polyurethanes.

Main Methods:

• Utilizing transcarbamoylation to induce topological network rearrangement in thermoset polyurethanes.
• Employing the Jianzhi (kirigami) technique to manipulate and observe shape-shifting behavior.
• Characterizing the material's response to induced network changes.

Main Results:

• A classical thermoset shape-memory polyurethane demonstrated unexpected permanent reshaping (plasticity).
• Topological network rearrangement via transcarbamoylation was identified as the key mechanism for plasticity.
• The Jianzhi technique revealed significant shape-shifting versatility in this material.

Conclusions:

• Thermoset shape-memory polyurethanes can overcome their inherent intractability and be permanently reshaped.
• Transcarbamoylation-induced network rearrangement is a viable strategy for achieving plasticity in thermosets.
• This finding has broad implications for shape-shifting applications and polymer design, given the prevalence of carbamate groups.