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It is a highly attractive strategy to develop chemically recyclable polymers to establish a circular plastic economy. Despite the recent advancements, chemically recyclable polymers still face challenges including high energy cost for polymer preparation or recycling, poor monomer recovery selectivity and efficiency as well as undesired material performance. In this contribution, we present the chemoselective controlled ring‐opening polymerization of bio‐renewable bifunctional α‐methylene‐δ‐valerolactone (MVL) to produce exclusive functionalizable polyester using strong base/urea binary catalysts. The obtained polyester with high molar mass exhibits good tensile strength comparable to that of some commodity plastics. Remarkably, the obtained polyester can be depolymerized to recover pristine monomer with a 96 % yield by thermolysis, thus successfully establishing a closed‐loop life cycle. [ABSTRACT FROM AUTHOR]

The development of chemically recyclable polymers presents the most appealing solution to address the plastics' end‐of‐use problem. Despite the recent advancements, it is highly desirable to develop chemically recyclable polymers from commercially available monomers to avoid the costly and time‐consuming commercialization. In this contribution, we achieve the controlled ring‐opening polymerization (ROP) of bio‐sourced δ‐caprolactone (δCL) using strong base/urea binary catalysts. The obtained PδCL is capable of chemical recycling to δCL in an almost quantitative yield by thermolysis. Sequential ROP of δCL and l‐lactide (l‐LA) affords well‐defined PLLA‐b‐PδCL‐b‐PLLA triblock copolymers, which behave as thermoplastic elastomers with excellent elastic recovery, tensile strength and ultimate elongation. The upcycling of PLLA‐b‐PδCL‐b‐PLLA to recover ethyl lactate and δCL with high yields is achieved by refluxing with ethanol and then distillation under reduced pressure. [ABSTRACT FROM AUTHOR]

Al complexes bearing amino-quinoline ligands rapidly converted hundreds even thousands equiv. of ε-CL into PCLs with high conversions in a living and/or immortal manner. [Display omitted] • A series of Al complexes (Al1 − Al5) bearing N,N-bidentate amino-quinoline ligands were synthesized and fully characterized. • Al complexes Al1 − Al5 could catalyze fast and living ring-opening polymerization (ROP) of ε -caprolactone (ε -CL). • Polycaprolactones (PCLs) with high molecular weights (M n up to 129 kDa) and narrow dispersity (Đ = 1.16) were readily synthesized. • An extremely low loading of Al complex (0.05 mol% to ε -CL monomer) was efficient for ROP of ε -CL to prepare PCL with desired M n and narrow distribution in an immortal manner. Catalysts drive innovation in sustainable polymers because of their reactivity and selectivity. In this context, the synthesis and characterization of a series of Al complexes (Al1 − Al5) bearing N,N-bidentate amino-quinoline ligands are described, as well as their applications in ring-opening polymerization (ROP) of ε -caprolactone (ε -CL). The amido-coordination Al complexes were directly synthesized by reactions of imino-quinoline compounds with AlMe 3 via methyl migration from Al to the carbon atom of imine, as indicated by both NMR spectroscopy and X-ray diffraction. In the presence of BnOH, complexes Al1 − Al5 showed significant reactivity for ROP of ε -CL with good control over molar mass (M n) and dispersity (Đ < 1.2), and polycaprolactones (PCLs) with high molecular weights (M n up to 129 kDa) were readily synthesized. Remarkably, immortal catalysis with excess of BnOH (up to 20 equiv. to Al) was achieved to prepare PCLs with predictable M n s, low dispersities, and end groups using an extremely low loading of Al complex (0.05 mol% to ε -CL monomer). [ABSTRACT FROM AUTHOR]