Floor Temperature‐regulated Poly(ether‐alt‐ester) With Thermal Stability and Chemical Recyclability Enabled by Polycondensation—Depolymerization−Repolymerization Strategy

Abstract Creating innovative poly(ether‐ alt ‐ester)s (PEAEs) with alternating ether and ester groups to address the trade‐offs between the polymer′s depolymerizability and thermostability is essentially important for advanced material applications and sustainable development. Current research efforts focus on modulating the ceiling temperature ( T c ) of monomers with small‐sized rings, to increase the thermostability of PEAEs at high temperature. Notably, floor temperature ( T f )−regulated PEAEs, obtained from entropy‐driven ring‐opening polymerization (ROP) of macrocyclic ether‐ester monomers, inherently exhibit enhanced thermodynamic stability as the temperature increases. However, high‐performance PEAEs regulated by T f remains long‐term underdeveloped owing to extremely low efficiency and selectivity in macrocyclic monomer synthesis. Herein, we developed a “polycondensation–depolymerization” strategy for macrocyclic ether‐ester monomer and presented the first example of T f ‐regulated PEAE with thermostability, melt processibility as well as chemical recyclability. The resulting PEAE is semi‐crystalline and ductile, and exhibits remarkable high decomposition temperature (with a T d,5% up to 378.3 °C) compared to the T c ‐regulated poly(1,4‐dioxan‐2‐one) (PPDO, T d,5% = 238.4 °C). This work corroborated the effectiveness of the T f ‐regulated PEAE in resolving the challenges associated with the T c ‐regulated analogs and provided a molecular‐level design principle for poly(ether‐ alt ‐ester) with high‐performance.