Optimized Polyurethane/CNTs Composite for Stress-Free Two-Way Shape Memory via Training Enhancement

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Thermally responsive shape memory polymers (SMPs) are intelligent materials with broad applications.
• Poor thermal conductivity limits the practical utility of conventional SMPs.
• Carbon nanotubes (CNTs) offer excellent thermal conductivity and photothermal properties.

Purpose of the Study:

• To enhance the thermal conductivity and shape memory performance of polyurethane.
• To investigate the integration of CNTs into a polyurethane matrix.
• To explore novel functionalities like shape reprogramming and remote manipulation.

Main Methods:

• Stepwise polymerization using hydroxyl terminated polycaprolactone (PCL-diOH), poly(ethylene glycol) (PEG), and hexamethylene diisocyanate (HDI).
• Integration of carbon nanotubes (CNTs) into the polyurethane matrix.
• Characterization of mechanical strength, thermal conductivity, and shape memory behavior.

Main Results:

• The resulting CNT-polyurethane composite demonstrated enhanced mechanical strength and thermal conductivity.
• The material exhibited superior shape memory performance, including a training enhancement phenomenon.
• Stress-free two-way shape memory behavior and vitrimer properties at 110 °C were achieved.
• Remote manipulation under light stimulation and multi-stimuli responsive shape memory were demonstrated.

Conclusions:

• CNTs significantly improve the thermal and mechanical properties of polyurethane shape memory composites.
• The developed composite offers advanced functionalities including shape reprogramming and multi-stimuli responsiveness.
• This material holds great potential for real-world applications requiring intelligent shape memory behavior.