CO ₂ -Based ABA Triblock Thermoplastic Elastomer with Readily Adjustable Performance

CO2-based polycarbonates have emerged as sustainable alternatives for the development of thermoplastic elastomers (TPEs). The objective of this study is to fabricate highly cost-effective CO2-based ABA triblock TPEs. Utilizing inexpensive and easily accessible monomers of ethylene oxide (EO), CO2, and tetrachlorophthalic anhydride (TCPA), high-molecular-weight copolymers (up to 49.9 kg/mol) were synthesized through a one-pot bulk polymerization strategy. The resulting triblock copolymer consists of polycarbonate P(EO-co-CO2) and polyester P(EO-co-TCPA) as soft and hard segments, respectively. Systematic optimization of segmental composition enabled the fabrication of a high-performance elastomer demonstrating exceptional mechanical robustness (tensile strength = 24.3 MPa), superior elasticity (elongation at break = 938%), and excellent reprocessability (10-cycle tensile–relaxation recovery = 64%). In addition, the material simultaneously possesses high hardness, excellent transparency, and barrier properties. Notably, the incorporation of minute quantities of long-chain oxide monomers has been shown to substantially enhance the elastic recovery rate of the synthesized elastomer while maintaining cost-effectiveness.