An elastomer with ultrahigh strain-induced crystallization.

Area of Science:

• Materials Science
• Polymer Chemistry
• Mechanical Engineering

Background:

• Strain-induced crystallization (SIC) enhances elastomer properties like strength, toughness, and elastocaloric effect.
• Common elastomers exhibit limited SIC (below 20%) and stretchability due to trapped entanglements.

Purpose of the Study:

• To develop elastomers with significantly higher strain-induced crystallinity and stretchability.
• To investigate the impact of novel polymer architecture on mechanical and elastocaloric properties.

Main Methods:

• Synthesized star polymers via end-linking followed by deswelling to create defect-free networks.
• Characterized the resulting deswollen end-linked star elastomers (DELSE) for crystallinity, stretchability, fracture energy, and elastocaloric effect.

Main Results:

• Achieved strain-induced crystallinity up to 50%, far exceeding common elastomers.
• Demonstrated ultrahigh stretchability (12.4 to 33.3), surpassing typical limits.
• Reported high fracture energy (4.2 to 4.5 kJ m⁻²) with low hysteresis.
• Observed a high elastocaloric effect with an adiabatic temperature change of 9.3°C.

Conclusions:

• The novel DELSE architecture overcomes entanglement limitations, enabling unprecedented SIC and stretchability.
• Synergistic enhancement of SIC and stretchability leads to superior elastocaloric performance.
• These findings pave the way for advanced elastomers with tailored mechanical and thermal properties.