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

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.