High-Performance Recyclable Polyester Elastomers Through Transient Strain-Stiffening

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Materials

Background:

• Polyester thermoplastic elastomers offer sustainability but often compromise mechanical properties like strength and elasticity.
• Achieving strong and tough elastomers typically involves complex formulations and cross-linking/crystallinity control, hindering recyclability.
• Current approaches face challenges in balancing mechanical performance with ease of recycling.

Purpose of the Study:

• To develop novel amorphous block polyester elastomers with improved mechanical properties and recyclability.
• To introduce transient strain-stiffening into fully amorphous structures for enhanced strength and toughness.
• To create sustainable elastomers that overcome the limitations of existing materials.

Main Methods:

• Controlled polymerization of commercial monomers to create block copolymers.
• Synthesis of amorphous block polyester elastomers with a central poly(ɛ-caprolactone-co-ɛ-decalactone) block and poly(cyclohexene oxide-alt-phthalate) flanking blocks.
• Tuning thermomechanical properties by adjusting the ratio of ɛ-caprolactone to ɛ-decalactone.

Main Results:

• The best elastomers (30-50 wt.% polycaprolactone) achieved tensile strengths up to 40 MPa and elongations at break >2000% with >90% elastic recovery.
• Materials exhibited strain-induced crystallization, outperforming commercial elastomers in tensile mechanical properties.
• Demonstrated a wide service temperature range (-60 to 140 °C), high thermal stability (≥300 °C), and excellent recyclability.

Conclusions:

• Transient strain-stiffening in amorphous block polyester elastomers enhances strength and toughness while preserving recyclability.
• These novel materials represent a significant advancement in sustainable elastomer technology.
• The developed elastomers offer a superior combination of mechanical performance, thermal stability, and recyclability.