Highly Tough, Notch-Insensitive, and Fast Self-Healing Thermoplastic Polyurethane Elastomers by Tailored Soft Segment...

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Achieving simultaneous toughness, notch insensitivity, and self-healing in thermoplastic polyurethanes (TPUs) is difficult.
• Hard domains in TPUs enhance strength but hinder healing; soft domains provide elasticity but are prone to damage.

Purpose of the Study:

• To develop a novel TPU system with improved mechanical properties and self-healing capabilities.
• To investigate the effect of branched polyacrylate soft segments on TPU performance.

Main Methods:

• Incorporation of α,ω-hydroxyl end-functionalized polyacrylates, specifically branched 2-ethylhexyl acrylate, into conventional TPU structures.
• Analysis of the impact of branched-alkyl acrylic soft segments on segmental dynamics and thermal responsiveness.

Main Results:

• The modified TPUs exhibit high toughness (186 MJ·m⁻³).
• Excellent notch insensitivity was observed, with fracture energy remaining above 197 kJ·m⁻² at elongations exceeding 900%.
• Significant self-healing was achieved, with approximately 90% recovery at 45°C within 3 hours.

Conclusions:

• Branched polyacrylate soft-segment engineering in TPUs offers a balanced pathway to achieve mechanical robustness and adaptability.
• Enhanced thermal responsiveness of branched segments promotes chain mobility and uniform stress distribution without compromising hard domain contributions.
• This approach yields high-performance TPU elastomers suitable for demanding applications.