Xianhong Wang

The pursuit of a sustainable, circular polyurethane (PU) economy has created a pressing need to develop chemically recyclable polyols capable of reconciling the inherent conflicts between the performance requirements during and after their life span. Polyacetal polyols offer a promising candidate for this purpose; however, their widespread adoption in PUs manufacturing has been persistently hindered by challenges in precision synthesis. Here, we demonstrate a highly efficient anion‐binding catalytic polymerization (ABCP) strategy for reversible‐deactivation cationic ring‐opening polymerization of cyclic acetals, using a selenocyclodiphosph(V)azane catalyst and a trimethylsilyl iodide initiator. This approach enables the long‐sought precision synthesis of poly(1,3‐dioxepane) (PDXP) diol—a representative polyacetal polyol—on the kilogram scale, with no detectable cyclic side‐products. This chemistry further enables the utilization of hydroxyl‐telechelic PDXP as an alternative to poly(tetramethylene ether glycol) diol in the preparation of both thermoplastic PUs and flexible foams. The resulting materials exhibit excellent mechanical properties and processability comparable to those of commercial polyether‐based PUs, while the PDXP soft segments in representative thermoplastic PU and crosslinked flexible foam can be depolymerized to regenerate 1,3‐dioxepane, and the hard‐segment‐enriched residue can be converted to 4,4'‐diaminodiphenylmethane, thereby demonstrating closed‐loop recycling of the PDXP soft segment together with chemical valorization of the hard‐segment‐derived fraction.

The pursuit of a sustainable, circular polyurethane (PU) economy has created a pressing need to develop chemically recyclable polyols capable of reconciling the inherent conflicts between the performance requirements during and after their life span. Polyacetal polyols offer a promising candidate for this purpose; however, their widespread adoption in PUs manufacturing has been persistently hindered by challenges in precision synthesis. Here, we demonstrate a highly efficient anion‐binding catalytic polymerization (ABCP) strategy for reversible‐deactivation cationic ring‐opening polymerization of cyclic acetals, using a selenocyclodiphosph(V)azane catalyst and a trimethylsilyl iodide initiator. This approach enables the long‐sought precision synthesis of poly(1,3‐dioxepane) (PDXP) diol—a representative polyacetal polyol—on the kilogram scale, with no detectable cyclic side‐products. This chemistry further enables the utilization of hydroxyl‐telechelic PDXP as an alternative to poly(tetramethylene ether glycol) diol in the preparation of both thermoplastic PUs and flexible foams. The resulting materials exhibit excellent mechanical properties and processability comparable to those of commercial polyether‐based PUs, while the PDXP soft segments in representative thermoplastic PU and crosslinked flexible foam can be depolymerized to regenerate 1,3‐dioxepane, and the hard‐segment‐enriched residue can be converted to 4,4'‐diaminodiphenylmethane, thereby demonstrating closed‐loop recycling of the PDXP soft segment together with chemical valorization of the hard‐segment‐derived fraction.

Isotactic poly(propylene oxide) (iPPO) is a robust polyether with photodegradability. However, its stereoselective synthesis from racemic propylene oxide (rac-PO) remains dominated by preconfigured axially chiral cobalt/chromium bimetallic catalysts. Here, we report an ion pair-assisted dynamic helical organization strategy employing a bifunctional multi-aluminum porphyrin (BMAlP) catalyst for stereocontrolled synthesis of iPPO. This approach affords highly isotactic PPO with [mm] up to 97.6%, ultrahigh viscometric molecular weight (Mv up to 6700 kDa), and a tensile strength of 92 MPa comparable to nylon-66. Mechanistic studies reveal that π–π interactions among polyacrylate-supported porphyrin generate dynamic P/M helical organizations, while ion pairs stabilize hierarchical organization and promote cooperative aluminum-site arrangement, creating locally persistent enantiomorphic catalytic environments for enantiomorphic-site-controlled PO insertion. This work establishes dynamic supramolecular chirality as an alternative strategy for stereoselective polymerization beyond static molecular chirality.

Superabsorbent polymers (SAPs) are widely used but remain dominated by nondegradable poly(acrylic acid)-based networks, creating sustainability concerns. Natural polymer-based alternatives often require acrylic acid grafting to achieve high absorbency, compromising degradability and structural uniformity. Synthetic biodegradable polymers offer molecular-level designability, but most backbones struggle to combine high-density hydrophilic functionalization with rapid swelling. Here, we demonstrate CO2-based polycarbonates derived from functional epoxides as a programmable platform for high-performance biodegradable SAPs. A lightly cross-linked poly(vinyl cyclohexene carbonate)-derived network with rigid backbones and two pendant sodium carboxylate groups per repeat unit combines high hydrophilicity with mechanical strength, delivering high absorption in deionized water (237 g·g–1), saline (∼41 g·g–1), and under load (∼12 g·g–1). It also exhibits ultrafast early-stage swelling dominated by Fickian diffusion, reaching 102 g·g–1 within 1 min, retaining ∼85% of its absorbency after 5 swelling–deswelling cycles, and achieving 61% biodegradation over 51 days, which falls within the reported range for polyhydroxybutyrate (PHB). These findings underscore the promise of CO2-derived polycarbonates as a customizable platform for producing high-performance, biodegradable superabsorbent materials.

The one‐step synthesis of well‐defined telechelic polymers represents a highly attractive approach, providing an efficient alternative to conventional stepwise synthetic protocols. However, achieving such control remains challenging due to the competitive nature of chain propagation and end‐group functionalization, which often leads to uncontrolled chain‐end structures and broad dispersities. Here, we report an alcohol‐mediated self‐switching strategy, in which the dominant chain‐end reaction shifts from propagation to end‐group functionalization upon consumption of one monomer component within a single reaction system. Using epichlorohydrin, a multisite monomer, as a model for the ring‐opening alternating copolymerization with cyclic anhydrides, we obtained well‐defined epoxide‐terminated telechelic polyesters with narrow dispersities ( Đ ∼ 1.1), high end‐group fidelity (>99%), and controllable linear, three‐arm, and four‐arm architectures under alcohol‐mediated conditions. Mechanistic studies reveal that monomer activation and stabilization of the living species through hydrogen‐bonding interactions, combined with the zero‐order kinetics of cyclic anhydride, facilitate rapid propagation while suppressing premature functionalization. Subsequent intramolecular cyclization of β‐chlorohydrin living chain ends, along with proton‐transfer‐induced dehydrochlorination of β‐chlorohydrin dormant chain ends, collectively ensure quantitative epoxide end‐group formation. These results elucidate the catalyst‐like roles of alcohol and establish self‐switching of competing chain‐end reactions as a practical strategy for the direct synthesis of well‐defined telechelic polymers.

The one‐step synthesis of well‐defined telechelic polymers represents a highly attractive approach, providing an efficient alternative to conventional stepwise synthetic protocols. However, achieving such control remains challenging due to the competitive nature of chain propagation and end‐group functionalization, which often leads to uncontrolled chain‐end structures and broad dispersities. Here, we report an alcohol‐mediated self‐switching strategy, in which the dominant chain‐end reaction shifts from propagation to end‐group functionalization upon consumption of one monomer component within a single reaction system. Using epichlorohydrin, a multisite monomer, as a model for the ring‐opening alternating copolymerization with cyclic anhydrides, we obtained well‐defined epoxide‐terminated telechelic polyesters with narrow dispersities ( Đ ∼ 1.1), high end‐group fidelity (>99%), and controllable linear, three‐arm, and four‐arm architectures under alcohol‐mediated conditions. Mechanistic studies reveal that monomer activation and stabilization of the living species through hydrogen‐bonding interactions, combined with the zero‐order kinetics of cyclic anhydride, facilitate rapid propagation while suppressing premature functionalization. Subsequent intramolecular cyclization of β‐chlorohydrin living chain ends, along with proton‐transfer‐induced dehydrochlorination of β‐chlorohydrin dormant chain ends, collectively ensure quantitative epoxide end‐group formation. These results elucidate the catalyst‐like roles of alcohol and establish self‐switching of competing chain‐end reactions as a practical strategy for the direct synthesis of well‐defined telechelic polymers.

The development of high-performance polyurethanes (PUs) is intrinsically connected to the molecular structure of polyol precursors. However, single-structure polyols, such as polyester polyols and polyether polyols, exhibit limited potential for broadly regulating PU properties. Herein, we engineered random poly(ether-ester-carbonate) polyols with tailored compositions via telomerization of anhydride/epoxide/CO₂ enabled by a robust supported aluminum porphyrin catalyst. Ultralow molecular weight polyols (0.8 kg/mol) with narrow dispersity (Đ = 1.08) were easily obtained due to the catalyst's extraordinary proton tolerance. Additionally, our supported catalyst produced near-white products while maintaining recyclability for at least three cycles. Our work provides a versatile platform for designing next-generation PU precursors.

Epoxy resins, exemplified by bisphenol A diglycidyl ether, are widely used in coatings, electronic packaging, and composite materials. However, the conventional NaOH-based synthesis lacks precision, as the harsh alkaline conditions inevitably induce side reactions such as oligomerization and hydrolysis, thereby compromising resin quality. Here, we report an organocatalytic epoxide apparent exchange reaction that enables the precise synthesis of bisphenol A diglycidyl ether from bisphenol A and epichlorohydrin, in which the β-chlorohydrin groups in the ether intermediates undergo apparent exchange with the epoxide groups in epichlorohydrin. Computational studies revealed that the alkoxide in situ generated from epichlorohydrin ring-opening facilitates a hydrogen-bonding-mediated proton-transfer pathway that induces the dehydrochlorination of the β-chlorohydrin groups, thereby forming the target epoxide groups. This approach provides broad applicability to the synthesis of most commercial epoxy resins. Furthermore, this mild method overcomes the structural limitations of the NaOH process, providing an alternative route to polyester-based epoxy resins and promoting the development of sustainable epoxy materials.

Supported catalysis is considered as an ideal catalytic mode as it combines the advantages of homogeneous catalysis (activity and selectivity) and heterogeneous catalysis (separation and recyclability). However, its application is greatly limited by the loss of catalytic performance after immobilization of molecular catalyst on supports. Inspired by the upright feeding posture of stalked crinoids—characterized by outstretched arms with ordered pinnules extending away from the substrate—we addressed this issue by immobilizing of a linear polymer catalyst decorated with aluminum porphyrin on silica. Our catalyst demonstrates remarkable productivity (62.4 kg polyols/g Al porphyrin), polymer selectivity (99%) and proton tolerance (320,000 equiv. to [Al]) under highly dilute conditions (0.000125 mol [Al]%, 17.8 ppm) for telomerization of CO₂ and epoxides, which is greatly improved compared to traditional systems. Furthermore, our catalyst exhibits stability and maintains catalytic performance after three cycles. Our strategy provides a rational approach to designing highly efficient supported catalysts.