Strong, Resilient, and Sustainable Aliphatic Polyester Thermoplastic Elastomers

Area of Science:

• Polymer Science
• Materials Science
• Sustainable Materials

Background:

• Thermoplastic elastomers (TPEs) offer versatile properties and processability due to physical cross-links.
• Poly(γ-methyl-ε-caprolactone) (PγMCL), an amorphous polymer, is suitable for tough elastomers due to its low entanglement molar mass.
• Polylactide (PLA) is a sustainable polymer often used in TPE formulations.

Purpose of the Study:

• To develop and characterize novel TPEs based on PγMCL and PLA.
• To investigate the structure-property relationships governing the mechanical performance of these sustainable TPEs.
• To compare the properties of these novel TPEs with commercially available styrene-based TPEs.

Main Methods:

• Synthesis of ABA block copolymers with PγMCL midblocks and PLA end blocks.
• Mechanical testing, including stress-strain analysis to determine tensile strength and elongation at break.
• Analysis of material properties including hysteresis, glass transition temperature, and crystallinity.

Main Results:

• TPEs with PγMCL midblocks and amorphous PLA end blocks exhibited high stress (24 ± 2 MPa) and elongation at break (1029 ± 20%).
• Utilizing semicrystalline isotactic PLA end blocks further enhanced material strength and toughness (30 ± 4 MPa, 988 ± 30%).
• The observed properties are attributed to polymer entanglements, glass transition temperature, segment-segment interactions, and crystallinity.

Conclusions:

• Novel sustainable TPEs with excellent mechanical properties were successfully developed.
• The combination of PγMCL and PLA results in materials with performance comparable to conventional styrene-based TPEs.
• Understanding the role of fundamental material parameters is key to designing high-performance, sustainable elastomers.