A Facile Approach to Construct Novel Polyesters as Soft Midblock for Thermoplastic Elastomers

The development of innovative synthetic strategies to create functional polycaprolactones is highly demanded for advanced material applications. In this contribution, we reported a facile synthetic strategy to prepare a class of CL‐based monomers (R‐TO) derived from epoxides. They readily polymerize via well‐controlled ring‐opening polymerization (ROP) to afford a series of polyesters P(R‐TO) with high molecular weight ( M n up to 350 kDa). Sequential addition copolymerization of MTO and L ‐lactide ( L ‐LA) allowed to access of a series of ABA triblock copolymers with composition‐dependent mechanical properties. Notably, P( L ‐LA) 100 ‐ b ‐P(MTO) 500 ‐ b ‐P( L ‐LA) 100 containing the amorphous P(MTO) segment as a soft midblock and crystalline P( L ‐LA) domain as hard end block behaved as an excellent thermoplastic elastomer (TPE) with high elongation at break (1438±204 %), tensile strength (23.5±1.7 MPa), and outstanding elastic recovery (>88 %).