Dynamic Disulfide Bond-Driven the Shape-Adaptive Self-Healing of Polyurethane Microcapsules

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Conventional isocyanate-based microcapsules offer limited self-healing, necessitating advanced repair systems.
• The development of intrinsic self-healing materials is crucial for extending material lifespan and reducing waste.

Purpose of the Study:

• To design and synthesize novel polyurethane microcapsules (PU1) with self-healing properties.
• To compare the self-healing performance of PU1 microcapsules against conventional microcapsules (PU2).
• To evaluate the mechanical properties of elastomer films derived from the novel microcapsules.

Main Methods:

• Synthesis of novel microcapsules (PU1) incorporating dynamic disulfide bonds.
• Comparative synthesis of conventional microcapsules (PU2) using 1, 4-butanediol.
• Characterization of microcapsule structure, particle size, and glass transition temperature (Tg).
• Assessment of self-healing efficiency after induced damage at elevated temperatures.
• Evaluation of tensile strength and elongation at break for prepared elastomer films.

Main Results:

• PU1 microcapsules exhibited a standard shell-core structure, with particle size influenced by stirring speed.
• PU1 microcapsules showed a glass transition temperature (Tg) of -53.2°C, compared to -45.0°C for PU2.
• Damaged PU1 microcapsules demonstrated effective self-healing after 24 hours at 60°C, while PU2 showed minimal self-healing.
• PU1 elastomer films achieved a tensile strength of 7.3 MPa and elongation at break of 1450%.

Conclusions:

• The novel disulfide-bond-containing polyurethane microcapsules (PU1) possess intrinsic self-healing capabilities.
• This design overcomes the non-repetitive healing limitations of traditional external self-healing materials.
• The excellent mechanical properties and self-healing performance of PU1 offer a promising approach for advanced functional materials.