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We report an aniline ligand (1) with two bis(pyrazolyl)alkane arms, and its cationic, dizinc complexes. XRD, NMR, and modelling of the dizinc complexes resulted in an unprecedented, dynamic μ-anilide core. Compared with published μ-phenolate analogues, our μ-anilide complexes show higher activity and divergent counterion trends in ring-opening polymerization of rac-lactide. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Discovery of unprecedented donor‐acceptor patterns can essentially enrich the chemistry of donor‐acceptor cyclopropanes. We herein introduce a concept of vinylogous fluorine stabilizing effect, which guides rational design of a novel donor‐acceptor cyclopropane employing gem‐difluorovinyl group as the electron donor, namely dFVCP. Application of such dFVCPs in a [3+2] cycloaddition with aldehydes and a controlled ring‐opening polymerization by a Mg(OTf)2/DIPEA/C(sp3)‐H initiator system have been demonstrated, providing direct access to fluorine‐containing tetrahydrofurans and all‐carbon main‐chain polymers. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Discovery of unprecedented donor‐acceptor patterns can essentially enrich the chemistry of donor‐acceptor cyclopropanes. We herein introduce a concept of vinylogous fluorine stabilizing effect, which guides rational design of a novel donor‐acceptor cyclopropane employing gem‐difluorovinyl group as the electron donor, namely dFVCP. Application of such dFVCPs in a [3+2] cycloaddition with aldehydes and a controlled ring‐opening polymerization by a Mg(OTf)2/DIPEA/C(sp3)‐H initiator system have been demonstrated, providing direct access to fluorine‐containing tetrahydrofurans and all‐carbon main‐chain polymers. [ABSTRACT FROM AUTHOR]

The issue of non-degradable petroleum-based plastic waste is a global challenge that requires urgent attention due to its harmful impact on humans and the environment. Biomass-based materials have garnered significant attention to address this challenge in recent times. Lignin, with its abundance, low price, and rich aromatic groups, is not only essential biomass but also a crucial material that can be utilized to produce biodegradable polymers. This review paper provides comprehensive knowledge of the synthesis and applications related to lignin, polyester, and lignin–polyester copolymers with a specific focus on organic polymer synthesis techniques and diverse applications. Beginning with lignin, the review explores various extraction methods from raw biomass resources aimed at enhancing its compatibility with polyester matrices. Next, we discuss lignin chemical modification methods that alter its chemical structure and properties, ultimately enhancing its integration with polyesters. Subsequently, the synthesis of polyester is examined, encompassing condensation polymerizations and ring-opening polymerizations. These methods are evaluated for their scalability and capability in producing tailored polymer chains suitable for copolymerization with lignin. The copolymerization strategies involving lignin and polyester are explored in detail, including graft-onto and graft-from approaches. Each method is discussed for its ability to control copolymer composition and properties, which are crucial for achieving desired material characteristics. In terms of applications, the review highlights the wide-ranging utility of lignin–polyester copolymers across industries such as packaging, construction, and separation. These polymers offer improved biodegradability, thermal stability, and mechanical strength compared to conventional polyesters, making them perfect candidates for novel sustainable materials. Overall, this review provides valuable insights into the synthesis methods and applications of lignin, polyester, and lignin–polyester copolymers offering a comprehensive overview of their potential for addressing environmental concerns and expanding the scope of lignin-derived materials in various industrial applications. [ABSTRACT FROM AUTHOR]

Polythioesters (PTEs) are emerging sustainable polymers for their degradability and recyclability. However, low polymerizability of monomers and extensive side reactions often hampered the polymerization process. Moreover, copolymers containing both thioester and other types of functional groups in the backbone are highly desirable but rarely accomplished owing to several synthetic challenges. Here, we report the ring‐opening cascade polymerization (ROCAP) of N‐(2‐(acetylthio)ethyl)‐glycine N‐carboxyanhydrides (TE‐NCA) to afford recyclable PTEs and unprecedented poly(thioester‐co‐peptoid)s (P(TE‐co‐PP)s) in a controlled manner. By developing appropriated carboxylic acid‐tertiary amine dual catalysts, intramolecular S‐to‐N acyl shift is coupled into the ROCAP process of TE‐NCA to yield products with dispersity below 1.10, molecular weight (Mn) up to 84.5 kDa, and precisely controlled ratio of thioester to peptoids. Random copolymerization of sarcosine NCA (Sar‐NCA) and TE‐NCA gives thioester‐embedded polysarcosine with facile backbone degradation while maintaining the water solubility. This work represents a paradigm shift for the ROP of NCAs, enriches the realm of cascade polymerizations, and provides a powerful synthetic approach to functional PTEs and P(TE‐co‐PP)s that are otherwise difficult or impossible to make. [ABSTRACT FROM AUTHOR]

A new aluminum complex (NSO)AlMe2 featuring a hydrogen bond donor on the ligand backbone has been synthesized via the reaction of AlMe3 with 1-((2-(isopropylamino)phenyl)thio)propan-2-ol (NSO-H) and spectroscopically characterized. In the complex, the aluminum atom is in a distorted tetrahedral coordination sphere determined by the anionic oxygen and neutral nitrogen atoms of the ligand and by the two carbon atoms of the alkyl groups. After proper activation, the complex (NSO)AlMe2 was able to promote the ring-opening polymerization of L-, rac-lactide, ε-caprolactone and rac-β-butyrolactone. The polymerization of rac-lactide was faster than that of L-lactide: in a toluene solution at 80 °C, the high monomer conversion of 100 equivalents was achieved in 1.5 h, reaching a turnover frequency of 63 molLA·molAl–1·h–1. The experimental molecular weights of the obtained polymers were close to those calculated, assuming the growth of one polymer chain for one added alcohol equivalent and the polydispersity indexes were monomodal and narrow. The kinetic investigation of the polymerization led to the determination of the apparent propagation constants and the Gibbs free energies of activation for the reaction; the terminal groups of the polymers were also identified. The complex (NSO)AlMe2 was active in harsh conditions such as at a very low concentration or in the melt using technical-grade rac-lactide. A relatively high level of activity was observed in the ring-opening polymerization of ε-caprolactone and rac-β-butyrolactone. DFT calculations were performed and revealed the central role of the NH function of the coordinated ligand. Acting as a hydrogen bond donor, it docks the monomer in the proximity of the metal center and activates it toward the nucleophilic attack of the growing polymer chain. [ABSTRACT FROM AUTHOR]

Treatment of two classes of oxazolinyl‐indolate ligand precursors with an equivalent trimethylaluminum reagent afforded four corresponding aluminum dimethyl complexes. Intramolecular functional groups were employed to switch coordination behaviors, resulting in the formation of two classes of five‐ or six‐membered aluminum metallocyclic complexes. The screening of the prepared aluminum complexes, mediated by 9‐anthracenemethanol as the initiating reagent in the ring‐opening polymerization of ε‐caprolactone, showed significant activities at room temperature. The aluminum compound ligated by 2‐(1H‐indol‐2‐yl)‐4,4‐dimethyl‐4,5‐dihydrooxazole possessed a suitable chelated ring size, and its intrinsic electronic properties maintained higher activity. [ABSTRACT FROM AUTHOR]

Gelatin methacrylate (GelMA) is a photo-cross-linkable biopolymer. A combination of GelMA with biodegradable polyesters such as PCL (poly‐ε‐caprolactone) and their triblock derivatives improve the mechanical properties of GelMA. PCL-PEG-PCL (PCEC) was synthesized using ring-opening polymerization of ε-caprolactone in the presence of polyethylene glycol (PEG). The GelMA- PCEC was fabricated using freeze-drying and 3D printing and their porosity, mechanical properties, and swelling behavior were investigated. Human dental pulp stem cells were cultured on the scaffolds for a period of 14 days and cell adhesion was evaluated by scanning electron microscopy. Cell viability was analyzed by MTT and osteogenic differentiation was evaluated by Alizarin red S. Results showed that the 3D-printed scaffold had higher water absorption rate, retaining its structure up to a strain of 0.2 %, and a higher Young's modulus compared to the freeze-dried scaffold. In terms of cell viability, the 3D-printed scaffold outperformed the freeze-dried scaffold with a percentage of 86 % and 63 % viability respectively. Moreover, the 3D-printed scaffold exhibited better osteodifferentiation with calcium deposition. Overall, these findings suggest that the 3D-printed scaffold may have advantages over the freeze-dried scaffold in tissue engineering applications that require high water absorption, elasticity, and cell viability. The fabricated scaffolds provided suitable cell proliferation. [ABSTRACT FROM AUTHOR]

Shape-memory polyester films having functional groups were prepared and further grafted onto poly(N-isopropylacrylamide) (PNIPAAm) via atom-transfer radical polymerization. The grafting point of PNIPAAm was controlled by changing the composition of good and poor solvents. In the case of graft polymerization using only good solvents, the film swells, and polymerization proceeds not only from the surface but also from the internal polymerization initiation points. By increasing the proportion of poor solvents, PNIPAAm was grafted onto the surface of the film without swelling. The samples grafted to the interior regions of the film exhibited a decrease in the shape-memory recovery rate and recovery speed, whereas the samples grafted only to the surface of the film exhibited high shape-memory properties. Furthermore, contact-angle measurements revealed that the surface-grafted polymer exhibited changes in surface properties in response to film deformation. Because the deformation of the film is a large change, on the order of several millimeters, the deformation of the manually stretched film was shown to control molecular-level changes on the surface. [ABSTRACT FROM AUTHOR]

Polylactide (PLA), a biocompatible and biodegradable polymer, is widely used in diverse biomedical applications. However, the industry standard for converting lactide into PLA involves toxic tin (Sn)‐based catalysts. To mitigate the use of these harmful catalysts, other environmentally benign metal‐containing agents for efficient lactide polymerization have been studied, but these alternatives are hindered by complex synthesis processes, reactivity issues, and selectivity limitations. To overcome these shortcomings, we explored the catalytic activity of Cu‐(Phe)2 and Zn‐(Phe)2 metal‐amino acid co‐assemblies as potential catalysts of the ring‐opening polymerization (ROP) of lactide into PLA. Catalytic activity of the assemblies was monitored at different temperatures and solvents using 1H‐NMR spectroscopy to determine the catalytic parameters. Notably, Zn‐(Phe)2 achieved >99% conversion of lactide to PLA within 12 h in toluene under reflux conditions and was found to have first‐order kinetics, whereas Cu‐(Phe)2 exhibited significantly lower catalytic activity. Following Zn‐(Phe)2‐mediated catalysis, the resulting PLA had an average molecular weight of 128 kDa and a dispersity index of 1.25 as determined by gel permeation chromatography. Taken together, our minimalistic approach expands the realm of metal‐amino acid‐based supramolecular catalytic nanomaterials useful in the ROP of lactide. This advancement shows promise for the future design of simplified biocatalysts in both industrial and biomedical applications. [ABSTRACT FROM AUTHOR]

α‐Methylene‐δ‐valerolactone (MVL) as a bio‐renewable bifunctional monomer has shown great promise to prepare closed‐loop recyclable polyester with pendent functionalizable double bond. However, the chemoselective ring‐opening polymerization (ROP) of MVL still faces challenges including low polymerization temperature, expensive catalyst as well as high catalyst loading. In this contribution, we present the chemoselective and controlled ROP of MVL using a simple organoaluminum complex [MeAl(BHT)2] (BHT=2,6‐di‐tert‐butyl‐4‐methylphenoxy), which can be easily prepared from commercially available trimethylaluminum and 2,6‐di‐tert‐butyl‐4‐methylphenol without purification. MeAl(BHT)2 exhibits much higher catalytic activity (TOF=668 h−1) than that of MeAl[Salen] (TOF=89 h−1), a commonly used organoaluminum catalyst. The high chemoselectivity and activity of MeAl(BHT)2 is proposed to originate from the cooperative activation of propagating chain‐ends and monomers via the “coordination‐insertion” mechanism. Remarkably, high‐molecular‐weight P(MVL)ROP can be prepared in bulk using MeAl(BHT)2, which is not accessible by the previous catalysts. This study may advance the development of closed‐loop recyclable polymers considering the easy preparation, low cost and good catalytic performance of MeAl(BHT)2. [ABSTRACT FROM AUTHOR]

AbstractPoly(δ-valerolactone) (PVL) is a polymer that has garnered significant researcher interest due to its intriguing features and prospective uses across numerous domains, particularly in medicine. This work aimed to assess the influence of the Lewis acidity of the bis(β-diketonate)Zr catalyst complex on the ring-opening polymerization of δ-valerolactone. The ligand in the compound contains an electron-donating group, specifically the methyl group (2a). Furthermore, electron-withdrawing groups employed include phenyl (2b–2c) and trifluoromethyl groups (2d). Characterization data indicate that PVL has been successfully synthesized with a bis(β-diketonate)Zr complex catalyst. The hierarchy of Lewis acid strength for the bis(β-diketonate)Zr complex is 2c > 2b > 2d ≫ 2a. The sequence of PVL DP from highest to lowest is 2b, 2c, 2d and 2a. Nonetheless, the elevated Lewis acidity of complex 2c does not provide PVL with the greatest degree of polymerization. The steric barrier of complex 2c, which contains two phenyl groups, is larger than that in complex 2b. Consequently, the coordination process of the nucleophilic monomer with the electrophilic zirconium central atom becomes increasingly difficult. [ABSTRACT FROM AUTHOR]

We report the continuous, gas-phase synthesis of α-methylene-δ-valerolactone (MVL) from δ-valerolactone (DVL) and formaldehyde (FA) over alkaline earth oxide catalysts. MgO, CaO, and BaO supported on silica (∼5 wt%) were active for MVL production (613 K, 0.4 kPa DVL, 1.2 kPa FA, 101 kPa total pressure). CaO and BaO showed 90% and 83% selectivity to MVL at ∼60% DVL conversion, respectively. Decreasing contact times improved MVL selectivity for all three catalysts, achieving near quantitative selectivity at DVL conversions <40% with CaO. Further studies with CaO indicated that increasing the FA partial pressure for a given DVL partial pressure negligibly changed conversion while maintaining high selectivity; however, increasing the reaction temperature generally resulted in lower MVL selectivity. Deactivation and carbon loss were attributed to non-volatile compound formation from series and parallel reactions that consume MVL and DVL and poison the catalyst surface. These side reactions were more pronounced at high temperatures and higher contact times. While slow deactivation poses a challenge, the catalyst could be fully regenerated by calcining at 773 K for 4 h under flowing air. As the product mixture of MVL and DVL is difficult to separate, we developed a selective polymerization strategy to convert either one or both monomers into valuable polymeric materials, thereby achieving efficient separation and concurrent polymer production. Using a model mixture of 30 wt% of MVL in DVL, vinyl-addition polymerization converted MVL to the corresponding vinyl polymer (PMVL)VAP in 98% yield, while DVL was recovered in 96% yield by distillation. Alternatively, ring-opening polymerization of the same mixture resulted in a DVL/MVL copolyester and separatable vinyl homopolymer P(MVL)VAP. [ABSTRACT FROM AUTHOR]

A series of epoxidized 1,2‐polybutadienes with various degrees of epoxidation are synthesized by the reaction of 1,2‐polybutadienes and m‐chloroperbenzoic acid. Additionally, the curing behavior of epoxidized 1,2‐polybutadienes with a cationic initiator and the relationship between epoxidation ratios and the dielectric, thermal, and mechanical properties of the cured materials are examined. [ABSTRACT FROM AUTHOR]

A comparative study of the copolymerization of racemic propylene oxide (PO) with CO2 catalyzed by racemic (salcy)CoX (salcy = N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-diaminocyclohexane; X = perfluorobenzoate (OBzF5) or 2,4-dinitrophenoxy (DNP)) in the presence of a [PPN]Cl ([PPN] = bis(triphenylphosphine)iminium) cocatalyst is performed in bulk at 21 °C and a 2.5 MPa pressure of CO2. The increase in the nucleophilicity of an attacking anion results in the increase in the copolymerization rate. Racemic (salcy)CoX provides a high selectivity of the copolymerization, which can be higher than 99%, and the living polymerization mechanism. Poly(propylene carbonate) (PPC) with bimodal molecular weight distribution (MWD) is formed throughout copolymerization. Both modes are living and are characterized by low dispersity, while their contribution to MWD depends on the nature of the attacking anion. The racemic (salcy)CoDNP/[PPN]DNP system is found to be preferable for the production of PPC with a high yield and selectivity. [ABSTRACT FROM AUTHOR]

The extensive utilization of plastic, as a symbol of modern technological society, has consumed enormous amounts of finite and non-renewable fossil resources and produced huge amounts of plastic wastes in the land or ocean, and thus recycling and reuse of the plastic wastes have great ecological and economic benefits. Closed-loop recyclable polymers with inherent recyclability can be readily depolymerized into monomers with high selectivity and purity and repolymerized into polymers with the same performance. They are deemed to be the next generation of recyclable polymers and have captured great and increasing attention from academia and industry. Herein, we provide an overview of readily closed-loop recyclable polymers based on monomer and polymer design and no-other-reactant-involved reversible ring-opening and addition polymerization reactions. The state-of-the-art of circular polymers is separately summarized and discussed based on different monomers, including lactones, thiolactones, cyclic carbonates, hindered olefins, cycloolefins, thermally labile olefin comonomers, cyclic disulfides, cyclic (dithio) acetals, lactams, Diels–Alder addition monomers, Michael addition monomers, anhydride–secondary amide monomers, and cyclic anhydride–aldehyde monomers, and polymers with activatable end groups. The polymerization and depolymerization mechanisms are clearly disclosed, and the evolution of the monomer structure, the polymerization and depolymerization conditions, the corresponding polymerization yield, molecular weight, performance of the polymers, monomer recovery, and depolymerization equipment are also systematically summarized and discussed. Furthermore, the challenges and future prospects are also highlighted. [ABSTRACT FROM AUTHOR]

Titanium complexes bearing 2-(arylideneamino)phenolates and 2-((arylimino)methyl)phenolates were synthesized, and their catalytic activities in the polymerization of ε-caprolactone and L -lactide were studied. Among five-membered ring Ti complexes bearing 2-(arylideneamino)phenolates, FCl-Ti exhibited the highest level of catalytic activity ([CL] : [FCl-Ti] = 100 : 1, where [CL] = 2 M, and conv. = 86% at 60 °C after 9 h). For six-membered ring Ti complexes bearing 2-((arylimino)methyl)phenolates, SCl-Ti exhibited the highest level of catalytic activity ([CL] : [SCl-Ti] = 100 : 1, where [CL] = 2 M, and conv. = 88% at 60 °C after 118 h). The five-membered ring Ti complexes bearing 2-(arylideneamino)phenolates exhibited a higher level of catalytic activity (6.1–12.8 fold for the polymerization of ε-caprolactone and 6.2–23.0 fold for the polymerization of L -lactide) than the six-membered ring Ti complexes bearing 2-((arylimino)methyl)phenolates. The density functional theory (DFT) results revealed that the free energy of the first transition state FH-Ti-TS1 is 36.49 kcal mol−1 which is lower than that of SH-Ti-TS1 (46.58 kcal mol−1), which was ascribed to the fact that the Ti–Nim bond (2.742 Å) of FH-Ti-TS1 is longer than that of SH-Ti-TS1 (2.229 Å) and reduces the repulsion between ligands. [ABSTRACT FROM AUTHOR]

Silicon (Si)‐based anodes offer high theoretical capacity for lithium‐ion batteries but suffer from severe volume changes and continuous solid electrolyte interphase (SEI) degradation. Here, we address these challenges by selective methylation of 1,3‐dioxolane (DOL), thus shifting the unstable bulk polymerization to controlled interfacial reactions and resulting in a highly elastic SEI. Comparative studies of 2‐methyl‐1,3‐dioxolane (2MDOL) and 4‐methyl‐1,3‐dioxolane (4MDOL) reveal that 4MDOL, with its larger ring strain and more stable radical intermediates due to hyperconjugation effect, promotes the formation of high‐molecular‐weight polymeric species at the electrode‐electrolyte interface. This elastic, polymer‐rich SEI effectively accommodates volume changes of Si and inhibits continuous side reactions. Our designed electrolyte enables Si‐based anode to achieve 85.4 % capacity retention after 400 cycles at 0.5 C without additives, significantly outperforming conventional carbonate‐based electrolytes. Full cells also demonstrate stable long‐term cycling. This work provides new insights into molecular‐level electrolyte design for high‐performance Si anodes, offering a promising pathway toward next‐generation lithium‐ion batteries with enhanced energy density and longevity. [ABSTRACT FROM AUTHOR]

Double metal cyanide (DMC) complexes represent a unique family of materials with an open framework structure. The main current application of these complexes in chemical industry is their use as catalysts (DMCCs) of the ring-opening polymerization of propylene oxide (PO), yielding branched polyols, highly demanded in production of polyurethanes and surfactants. The actual problem of chemical fixing carbon dioxide from the atmosphere gave new impetus to the development of DMCCs, which turned out to be effective in oxirane/CO2 copolymerization. In recent years, new types and formulations of DMCCs were created, so that greater understanding of the reaction mechanisms was achieved and new fields of catalytic applications were found. In the present review, we summarized background and actual information about the synthesis, structure, and mechanisms of the action of DMCCs, as well as their application in the development of new materials and fine chemicals. [ABSTRACT FROM AUTHOR]

Polyesters (PEs) are sustainable alternatives for conventional polymers owing to their potential degradability, recyclability, and the wide availability of bio-based monomers for their synthesis. Herein, we used a one-pot, one-step self-switchable polymerization linking the ring-opening alternating copolymerization (ROAC) of epoxides/cyclic anhydrides with the ring-opening polymerization (ROP) of L-lactide (LLA) to synthesize PE-based hot-melt adhesives with a high bio-based content. In the cesium pivalate-catalyzed self-switchable polymerization of glutaric anhydride (GA), butylene oxide (BO), and LLA using a diol initiator, the ROAC of GA and BO proceeded whereas the ROP of LLA simultaneously proceeded very slowly, resulting in a copolyester consisting of poly(GA-alt-BO) and poly(L-lactide) (PLLA) segments with tapered regions, that is, PLLA-tapered block-poly(GA-alt-BO)-tapered block-PLLA (PLLA-tb-poly(GA-alt-BO)-tb-PLLA). Additionally, a series of tapered-block or real-block copolyesters consisting of poly(anhydride-alt-epoxide) (A segment) and PLLA (B segment) with AB-, BAB-, (AB)3-, and (AB)4-type architectures of different compositions and molecular weights were synthesized by varying the monomer combinations, alcohol initiators, and initial feed ratios. The lap shear tests of these copolyesters revealed an excellent relationship between the adhesive strength and polymer structural parameters. The (AB)4-type star-block copolyester (poly(GA-alt-BO)-tb-PLLA)4 exhibited the best adhesive strength (6.74 ± 0.64 MPa), comparable to that of commercial products, such as PE-based and poly(vinyl acetate)-based hot-melt adhesives. [ABSTRACT FROM AUTHOR]

Poly(L-lactic acid) (PLLA) and poly(ε-caprolactone) (PCL), two biodegradable and biocompatible polymers that are commonly used for biomedical applications, are, respectively, the result of the ring-opening polymerization of LA and ε-CL, cyclic esters, which can be produced according to several mechanisms (cationic, monomer-activated cationic, anionic, and coordination-insertion), except for L-lactide, which is polymerized only by anionic, cationic, or coordination-insertion polymerization. A series of well-defined PLLA-b-PCL block copolymers have been obtained starting from the same PLLA homopolymer, having a molar mass of 2500 g·mol−1, and being synthesized by coordination-insertion in the presence of tin octoate. PCL blocks were obtained via a cationic-activated monomer mechanism to limit transesterification reactions, and their molar masses varied from 1800 to 18,500 g·mol−1. The physicochemical properties of the copolymers were determined by 1H NMR, SEC, and DSC. Moreover, a series of nanoparticles (NPs) were prepared starting from these polyester-based copolymers by an emulsification/evaporation method. The sizes of the obtained NPs varied between 140 and 150 nm, as a function of the molar mass of the copolymers. Monomodal distribution curves with PDI values under 0.1 were obtained by Dynamic Light Scattering (DLS) and their spherical shape was confirmed by TEM. The increase in the temperature from 25 to 37 °C induced only a very slight decrease in the NP sizes. The results obtained in this preliminary study indicate that NPs have a temperature stability, allowing us to consider their use as drug-loaded nanocarriers for biomedical applications. [ABSTRACT FROM AUTHOR]

Polyacrylonitrile (PAN) is a promising polymer for solid‐state lithium (Li) metal batteries (SSLMBs). However, the low ionic conductivity of PAN‐based solid polymer electrolytes (SPEs) and unstable Li/PAN interface hinder the applications of PAN in SSLMBs. Herein, a strategy of ring‐opening polymerization is proposed to reconfigure the PAN‐based SPE network. Triggered by the alkaline species from Li6.4La3Zr1.4Ta0.6O12 nanoparticles, ethylene carbonate (EC) undergoes nucleophilic ring‐opening reaction, and subsequently forms dipole–dipole interaction with the PAN chain. This polymerization process consequently reconfigures PAN segment, endowing the SPE with rapid Li+ transport channels and enhanced interfacial stability with Li metal. As a result, the designed PAN‐based SPE demonstrates high ionic conductivity of 2.96 × 10−4 S cm−1 and Li+ transference number of 0.56 at 25 °C. The Li/Li symmetric cells with the reconfigured PAN network deliver a high critical current density of 1.8 mA cm−2 and maintain stable Li plating/stripping for 1200 h. A high‐capacity retention of 90.1% after 1000 cycles at 2 C is achieved in LiFePO4 (LFP)/Li solid‐state cells with PAN‐based SPEs. Moreover, the LFP/Li and LiNi0.8Co0.1Co0.1O2/Graphite pouch batteries both present good cycling and safety performances. This strategy provides new insights into designing high‐performance PAN‐based SPE for SSLMBs. [ABSTRACT FROM AUTHOR]

Simple and commercially available Lewis acids (LAs) are commonly used catalysts in anionic ring‐opening polymerization (AROP) reactions. In particular, for the AROP of epoxides, the addition of a Lewis acid allows the transition from a so‐called end‐chain mechanism to a monomer‐activated mechanism. The presence of the LA simultaneously leads to a decrease in the reactivity of active centers through the formation of a three‐species ate complex and to the activation of the monomer by LA coordination to the oxygen atom of the oxirane ring. These two effects result in both an increase in propagation kinetics and a decrease in transfer reactions, which has enabled the synthesis of high molecular weight polyethers. However, the impact of Lewis acids goes far beyond these classic effects. They have indeed enabled the polymerization of new functional monomers as well as the synthesis of heterotelechelic macromolecules. Also widely used as catalysts in copolymerization reactions (statistical, sequential, and alternating) Lewis acids can strongly influence the composition and sequence of monomer units in macromolecules. Finally, Lewis acids can also significantly influence the architecture of the obtained macromolecules. This review aims to list the various contributions of Lewis acids to macromolecular engineering and illustrate them with well‐chosen examples. [ABSTRACT FROM AUTHOR]

The poly(phenolic ester)s are attracting growing attention due to their essential role in the application as biodegradable plastics. Thus, extensive efforts have been devoted to the development of methodology that allows facile preparation of poly(phenolic ester)s with controlled molecular weights for widespread utilities. However, it is highly challenging to introduce phenolic ester bond structure into polyesters from ring‐opening polymerization (ROP) to yield aromatic/semiaromatic poly(phenolic ester)s due to severe transesterification reactions. To synthesize poly(phenolic ester)s with desired structures and properties, scientists have developed various ring‐opening polymerization systems with distinct advantages. Here, we have summarized basic features and recent progresses of these methods, including the cyclic phenolic lactone polymerization system, the salicylic acid O‐carboxyanhydride polymerization system, and the dissymmetric cyclic phenolic lactide polymerization system, as well as other copolymerization routes. Furthermore, the advantages and unsettled problems in various synthetic ways are discussed for readers to choose fast and controllable ROP systems for poly(phenolic ester)s. [ABSTRACT FROM AUTHOR]

Polymer stereocomplex formation represents a promising research area as it can improve thermal and mechanical properties of co‐crystallized polymer strands of opposite chirality. Polymers that form stereocomplexes commonly feature high stereoregularity and usually require sourcing from enantiopure monomer building blocks. Herein, we report the in situ polyether stereocomplex formation from racemic epoxide monomers, i.e., substituted methyl phenyl glycidyl ethers. The bio‐renewable glycidyl ethers were explored in both enantio‐ and isoselective ring‐opening polymerizations (ROPs), resulting in isotactic poly(phenyl glycidyl ether). While the enantioselective ROP selectively resolves a single enantiomeric, isotactic polyether stereoisomer ([mm]P≥78 %), the isoselective ROP leads to the concurrent formation of both isotactic (R)‐ and (S)‐poly(phenyl glycidyl ether) stereoisomers ([mm]P≥92 %) and thus results directly in a stereoisomer blend, which forms a stereocomplex. This is one of only a few polymer stereocomplexes generated directly during polymerization from a racemic monomer mixture. Stereocomplexes of the different poly(phenyl glycidyl ether)s show an increase in melting temperature of up to 76 °C, relative to the enantiopure parent polymers. The position of the methyl group at the phenyl ring determines both stereocomplex formation and the thermal properties of the resulting materials. [ABSTRACT FROM AUTHOR]

Selective polymerization with heterogeneous catalysts from mixed monomers remains a challenge in polymer synthesis. Herein, we describe that nano-sized zinc glutarate (ZnGA) can serve as a catalyst for the selective copolymerization of phthalic anhydride (PA), propylene oxide (PO) and lactide (LA). It was found that the ring-opening copolymerization (ROCOP) of PA with PO occurs firstly in the multicomponent polymerization. After the complete consumption of PA, the ring-opening polymerization (ROP) of LA turns into the formation of block polyester. In the process, the formation of zinc–alkoxide bonds on the surface of ZnGA accounts for the selective copolymerization from ROCOP to ROP. These results facilitate the understanding of the heterogeneous catalytic process and offer a new platform for selective polymerization from monomer mixtures. [ABSTRACT FROM AUTHOR]

An orthogonal agent having both alcohol and acylazide groups was used to construct novel polyurethanes by a simple synthetic process. Ring‐opening polymerization (ROP) of δ‐valerolactone from the orthogonal agent afforded a crystalline polymer having acylazide initiation end, while that of δ‐decanolactone resulted in an amorphous polymer. Since acylazide groups undergo thermally induced Curtius rearrangements to yield isocyanate groups, simple heating of above polymers gave macromonomers having both an isocyanate initiation end and an alcohol termination end, which afforded corresponding polyurethane by self‐polyaddition in a bulk condition without any additives. Meanwhile, kinetic analysis of the Curtius rearrangement revealed that a quantitative conversion was reached within a short reaction time, for example at 110°C for 30 min, or at 100°C for 1 h. Moreover, obtained polyurethane species showed unique self‐immolative type thermal degradation behavior. Considering the above, this orthogonal agent turned out to be useful to construct various polyurethane structures by a facile synthetic process, which would contribute to precise polymer synthesis and sequence defined polymer synthesis. [ABSTRACT FROM AUTHOR]

The development of modern society is closely related to polymer materials. As a typical example, plastic is an indispensable material in modern society. However, despite their low cost and widespread use, most discarded polymers are not recyclable, and their widespread use leads to the depletion of natural resources. In addition, the accumulation of polymer materials and their evolution in the environment can also cause serious environmental problems. Although the polymers can be reused by physical recovery, the properties of the polymers produced by this process are significantly reduced. Chemical recycling to original monomers for repolymerization offers a promising closed‐loop method to transition from a linear plastic economy toward a more sustainable circular model. This review focuses on recent developments and outlines future challenges of emerging chemically recyclable polyesters. [ABSTRACT FROM AUTHOR]

We present the synthesis, structural characterization, and reactivity studies of a tetra‐zinc complex supported by the bisphenoxymethanone ligands and its transformation into various di‐zinc architectures. Our findings highlight the potential of these complexes in molecular recognition, supramolecular chemistry, and catalysis. [ABSTRACT FROM AUTHOR]

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 (Mn 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 %). [ABSTRACT FROM AUTHOR]

Numerous zinc complexes based on N‐ and O‐donor Schiff‐base ligands have shown great promise in the ring‐opening polymerization (ROP) of lactides, which are cyclic dimers of lactic acid, to produce poly(lactic acid) (PLA). This is primarily because zinc is a borderline metal, making it non‐cytotoxic, inexpensive, abundant, biocompatible, and environmentally safe. Additionally, Schiff‐based ligands offer stability, stereoselectivity, desirable electronic and steric environments, and resistance to impurities. As a result, zinc complexes are easy to synthesize, colourless, have high reactivity and solubility in organic solvents, and are manageable under typical circumstances. Furthermore, these complexes are free to adopt a variety of coordination numbers since zinc does not have ligand field stabilization energy (LFSC). Zinc complexes possess high catalytic activity due to their distinctive properties, including high Lewis acidity, high electron transfer ability, stability concerning the reactive intermediate, and the ability to monitor polymerization by nuclear magnetic resonance (NMR) spectroscopy. Moreover, these complexes also have reasonable control over stereochemistry, number‐average molecular weight (Mn), and dispersity index (Ð). These advantages make it possible to produce colourless PLA with a high yield, high molecular weight, and narrow dispersity index in bulk and solvent‐based conditions. [ABSTRACT FROM AUTHOR]

A series of triphenol‐diamine‐type hyperbranched benzoxazines are synthesized by using polyformaldehyde, 1,1,1‐tri(4‐hydroxyphenyl) ethane, and primary amines such as p‐phenylenediamine, 4,4′‐diaminodiphenylmethane, polyetheramine, and bifuranocyclic diamine via Mannich condensation. Then, copolymers with bifunctional benzoxazine (BA‐a) are prepared to obtain superior properties. The polymerization behavior of the copolymers examined using a differential scanning calorimeter and a Fourier transform infrared indicates that the introduction of hyperbranched benzoxazines facilitates the benzoxazine curing reaction, decreasing the onset and peak temperatures of the curing process. Thermogravimetric analysis results suggest the cured hyperbranched benzoxazine demonstrates good thermal stability and can improve the heat resistance of benzoxazine. In addition, dynamic mechanical analysis suggests the glass transition temperature of the copolymers with BA‐a was increased after copolymerization, thus making all the copolymers obtain higher service temperatures. The test results from the universal testing machine and the fracture morphologies of copolymers indicate the hyperbranched benzoxazines with branched structures cause dendritic folds to appear on the surface of copolymers upon polymerization, preventing rapid cracking and spreading of the thermoset resin by dissipating more impact energy through this irregular dendritic appearance, thus obtaining strength and toughness superior to that of BA‐a resins. [ABSTRACT FROM AUTHOR]

New and simple ligand design strategies for the preparation of versatile metal-based catalysts capable of operating under greener and eco-friendly conditions in several industrially attractive processes are in high demand for society development. We present the first nucleophilic addition of an organolithium to ketenimines which incorporates a stereogenic centre in an N-donor atom to prepare new enantiopure NNN-donor scorpionates. We have also verified its potential utility as a valuable scaffold for chirality induction through the preparation of inexpensive, non-toxic and asymmetric zinc complexes. The pro-ligands and the corresponding zinc-based complexes have been characterized by X-ray diffraction studies. DFT studies were carried out to rationalize the different complexation abilities of these pro-ligands. These complexes have proved to act as highly efficient catalysts for a variety of sustainable bioresourced processes that are industrially attractive, with a wide substrate scope. Thus, complex 7 behaves as a highly efficient initiator for the well-behaved living ring-opening polymerization (ROP) of rac-lactide under very mild conditions. The PLA materials produced exhibited enhanced levels of isoselectivity, comparable to the highest value reported so far for zinc-based catalysts (Pi = 0.88). In addition, the combination of 7 with onium halide salts functioned as a very active and selective catalyst for CO2 fixation into five-membered cyclic carbonates through the cycloaddition of CO2 into epoxides under very mild and solvent-free conditions, reaching very good to excellent conversions (TOF = 227 h−1). Furthermore, this bicomponent system exhibits a broad substrate scope and functional group tolerance, including mono- and di-substituted epoxides, as well as the very challenging bio-renewable tri-substituted terpene-derived cis/trans-limonene oxide, whose reaction proceeds with high stereoselectivity. Finally, complex 7 also achieved high activity and selectivity as a one-component initiator for the synthesis of poly(cyclohexene carbonate)s via ring-opening copolymerization (ROCOP) of cyclohexene oxide and CO2 under very soft conditions, affording materials with narrow dispersity values. [ABSTRACT FROM AUTHOR]

Fourteen new phenoxy-azo aluminium complexes comprising two series, namely, dimethyl{phenoxy-azo}aluminium complexes 1a–7a and monomethyl{phenoxy-azo}aluminium complexes 1b–7b, were successfully synthesised and characterised. The molecular structure of complex 4a, determined using X-ray diffraction analysis, displayed a distorted tetrahedral geometry. The 1H NMR spectrum of complex 5b revealed fluxional behaviour caused by isomeric transformation that occurs in the solution at room temperature. The activation parameters determined by lineshape analysis of variable-temperature 1H NMR spectra in toluene-d8 are as follows: ΔH‡ = 70.05 ± 1.19 kJ mol−1, ΔS‡ = 21.78 ± 3.58 J mol−1 K−1 and ΔG‡ (298 K) = 63.56 ± 0.11 kJ mol−1. All aluminium complexes are active initiators for the ring-opening polymerisation of rac-lactide, and the polymerisations proceeded in a controlled manner and were living. In comparison, the catalytic activity of the dimethyl{phenoxy-azo}aluminium complexes was insignificantly different from that of the corresponding monomethyl{phenoxy-azo}aluminium complexes. The steric factor of the ortho-phenoxy substituent was observed to exert a decelerating effect on the catalytic rate. Kinetic investigations revealed first-order dependency on both monomer and initiator concentrations. Comparative catalytic investigations conducted on phenoxy-azo aluminium and phenoxy-imine aluminium complexes revealed that the former complexes exhibited lower catalytic activity. [ABSTRACT FROM AUTHOR]

A series of rare earth alkoxides bearing amine‐bridged bis(phenolato) ligands were synthesized through sequential reactions of RE(C5H5)3(THF) (RE = Y, Lu) or Nd[N(SiMe3)2]3 with bis(phenols) LH2 and CF3CH2OH. Complexes REL(OCH2CF3)(THF)n (1–6) bearing different aryl‐substituents were obtained in good yields of 59–70 %. They were applied in the ring‐opening polymerization (ROP) of rac‐β‐butyrolactone (rac‐BBL), which showed good activity (TOF up to 27,300 h−1), resulting in syndiotactically enriched poly(3‐hydroxybutyrate) (PHB) (Pr up to 0.86) with narrow polydispersities (PDI ≤ 1.27). The yttrium complex 3 bearing bulky o‐1,1‐diphenylethyl substituents outperformed other complexes, suggesting that the smaller ionic radii of metal centers and bulky ortho substituents of ancillary ligands play crucial roles in controlling the activity and stereoselectivity in ROP of rac‐BBL. Kinetics of the polymerization of rac‐BBL initiated by complex 3 was investigated, which revealed first order dependences on the monomer and initiator concentrations, respectively. [ABSTRACT FROM AUTHOR]

Herein we demonstrate an effective and facile end‐capping technique for ring‐opening metathesis polymerization (ROMP) using readily available allyl compounds as a new type of terminating agents. This new type of end‐capping reactions, which are based on the base‐promoted decomposition of ruthenocyclobutane intermediates, introduce diene moiety onto the chain end of ROMP polymers while simultaneously deactivating the ruthenium complex. These termination reactions are highly efficient, typically completing within 1 minute at 0 °C with >95 % end‐capping fidelity. [ABSTRACT FROM AUTHOR]

As the demand for sustainable polymers increases, most research efforts have focused on polyesters, which can be bioderived and biodegradable. Yet analogous polythioesters, where one of the oxygen atoms has been replaced by a sulfur atom, remain a relatively untapped source of potential. The incorporation of sulfur allows the polymer to exhibit a wide range of favorable properties, such as thermal resistance, degradability, and high refractive index. Polythioester synthesis represents a frontier in research, holding the promise of paving the way for eco‐friendly alternatives to conventional polyesters. Moreover, polythioester research can also open avenues to the development of sustainable and recyclable materials. In the last 25 years, many methods to synthesize polythioesters have been developed. However, to date no industrial synthesis of polythioesters has been developed due to challenges of costs, yields, and the toxicity of the by‐products. This review will summarize the recent advances in polythioester synthesis, covering step‐growth polymerization, ring‐opening polymerization (ROP), and biosynthesis. Crucially, the benefits and challenges of the processes will be highlighted, paying particular attention to their sustainability, with the aim of encouraging further exploration and research into the fast‐growing field of polythioesters. [ABSTRACT FROM AUTHOR]

Stable and inexpensive catalysts are particularly important in the catalysis industry. This study investigated cheap stable Ce2O3 and CeO2 as catalysts for the ring-opening polymerization of rac-lactide (rac-LA) and ε-caprolactone (ε-CL). Both Ce2O3 and CeO2 effectively catalyzed the polymerization of lactones. The catalytic efficiency of Ce2O3 was significantly higher than that of CeO2. The catalytic polymerization process was carried out under controlled conditions, and narrow molecular-weight distributions of polylactide and polycaprolactone were obtained. A kinetic study of the catalytic polymerization of rac-LA showed that the polymerization conformed to first-order kinetics and was controllable. [ABSTRACT FROM AUTHOR]

The model precatalyst sp3- and sp2-N dinitrogen-coordinated zinc–heteroimidazole has been used as an efficient catalyst for the ring-opening polymerization of cyclic esters. Subsequent to our exceptional active 5,6,7-trihydroquinolin-8-amine-zinc catalysts for the ring-opening polymerization (ROP) of ε-caprolactone, various pyridine-fused cycloalkanones (ring size from five to eight) are developed for the correspondent fused amine–pyridine derivatives and their zinc–heteroimidazole chloride complexes Zn1–Zn8 (LZnCl2) bearing N-diphenylphosphinoethyl pendants. Activated with two equivalents of LiN(SiMe3)2, the title zinc complexes efficiently promote the ROP of L-lactide (L-LA) in situ; among them, Zn4/2Li(NSiMe3)2 catalyzed 500 equivalent L-LA at 80 °C with 92% conversion in 5 min (TOF: 5520 h−1). Under the same conditions, the catalytic efficiency for the ROP of rac-LA by Zn1–Zn8/2Li(NSiMe3)2 was slightly lower than that for L-LA (highest TOF: 4440 h−1). In both cases, cyclooctyl-fused pyridyl–zinc complexes exhibited higher activity than others, while the cycloheptyl-fused zinc complexes showed the lowest activity. The microstructure analysis of the polymers showed they possessed a linear structure capped with CH3O as major and cyclic structure as minor. In this work, all the ligands and zinc complexes were well characterized by 1H/13C/31P NMR, FT-IR spectroscopy as well as elemental analysis. [ABSTRACT FROM AUTHOR]

The synthesis of poly(4-vinylbenzyl-g-β-butyrolactone) (poly(VB-g-BL)) graft copolymer was carried out by “click” chemistry of terminal azido poly(4-vinylbenzyl chloride) (PVB-N3) and terminal propargyl poly(β-butyrolactone) (β-BL-propargyl). For this purpose, poly(4-vinylbenzyl chloride) (poly-4-VBC) was obtained using 4-vinylbenzyl chloride and 2,2′-azobis(2-methylpropionitrile) by free-radical polymerization. PVB-N3 was synthesized using sodium azide and poly-4-VBC. β-BL-propargyl was obtained by the reaction of β-butyrolactone monomer with propargyl alcohol via ring-opening polymerization. The graft copolymer was also synthesized via “click” chemistry, employing PVB-N3 and β-BL-propargyl. The products were thoroughly characterized by GPC, FT-IR, SEM, and 1H-NMR. DSC and TGA were used to track the graft copolymer’s thermal characteristics. Thermal and spectroscopic measurements verified that the reactions were effectively completed. Poly(4-vinylbenzyl chloride) was obtained by free-radical polymerization. Terminal azido poly(4-vinylbenzyl chloride) was synthesized using sodium azide and poly(4-vinylbenzyl chloride). Terminal propargyl poly(β-butyrolactone) was obtained by β-butyrolactone and propargyl alcohol via ring-opening polymerization. Poly(4-vinylbenzyl-g-β-butyrolactone) graft copolymer was synthesized by “click” chemistry. Thermal and spectroscopic measurements verified that the reactions were completed. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Copolymerization as an efficient strategy can provide an opportunity to create new closed‐loop recyclable polymeric materials with tailored properties that are generally inaccessible to the individual homopolymers. In this contribution, the bulk ring‐opening copolymerization of bio‐renewable δ‐caprolactone and trans‐hexahydro‐(4,5)‐benzofuranone was achieved to produce closed‐loop recyclable copolyesters by using an organobase/urea binary catalyst at room temperature. The obtained copolyesters exhibited composition‐dependent thermal properties. Remarkably, the obtained copolyesters were able to depolymerize back to recover the corresponding monomers under mild conditions. The copolyesters with suitable compositions can be directly used as pressure‐sensitive adhesives (PSAs) that possessed comparable peel strength with the commercially available PSA scotch tapes. When the copolyesters were mixed with plasticizers, the as‐prepared PSAs exhibited desirable adhesive failure and can be used as removable post‐it note. [ABSTRACT FROM AUTHOR]

The n-butyltin(IV) trichloride (nBuSnCl3) initiator was successfully utilized in the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) under solvent-free conditions. Its reactivity was investigated by the non-isothermal differential scanning calorimetry (DSC). Effect of nBuSnCl3 concentration on the ROP of ε-CL was investigated by the Kissinger and model fitting methods. The obtained activation energy (Ea) values for the ROP of ε-CL with 1.0 mol% of nBuSnCl3 were higher than 2.0, and 4.0 mol%, respectively. Furthermore, the degree of aggregation (m) of nBuSnCl3 in the ROP of ε-CL was determined by the DSC technique. From the obtained m values at 120 and 140 °C, nBuSnCl3 presented in a non-aggregated state in the non-isothermal ROP of ε-CL. The performance of nBuSnCl3 was also compared with the di-n-butyltin(IV) dichloride (nBu2SnCl2) and tri-n-butytlin(IV) chloride (nBu3SnCl). The number of chloride and n-butyl groups adjacent to the Sn active center significantly affected the solvent-free ROP of ε-CL. From the non-isothermal DSC measurement, the polymerization exotherms for the ROP of ε-CL with nBuSnCl3 occurred and were completed at a lower temperature range than nBu2SnCl2, and nBu3SnCl, respectively. The Ea value for the ROP of ε-CL initiated by nBu3SnCl was higher than nBu2SnCl2, and nBuSnCl3, respectively. The values of pre-exponential factor (lnA) for the ROP of ε-CL initiated by nBu3SnCl, nBu2SnCl2, and nBuSnCl3 were determined from the first order reaction model fitting (f(α) = 1−α) and compensation effect. The kinetics data demonstrated that the reactivity of nBuSnCl3 was higher than nBu2SnCl2, and nBu3SnCl due to the lowest steric hindrance and the highest Lewis acidity of nBuSnCl3. Larger-scale (250 g) polymerization of ε-CL was preliminarily investigated by using the highly reactive nBuSnCl3 initiator. nBuSnCl3 could effectively produce PCL with weight average molecular weight (Mw) of 7.1 × 104 g/mol and 82% yield at 150 °C for 24 h. The probable mechanism of the ROP of ε-CL with nBu3SnCl was proposed via the coordination-insertion mechanism. [ABSTRACT FROM AUTHOR]

Poly(lactide‐co‐glycolide) (PLGA) is a biodegradable copolymer and widely used in pharmaceuticals. Commercially available PLGAs are produced through ring‐opening polymerization, which results in inevitable dispersity in molecular weight and chemical composition (i.e., lactide‐to‐glycolide ratio), influencing bulk properties such as degradation, mechanics, and morphology. In this study, an automated chromatographic separation technique was employed to generate a series of well‐defined, low‐dispersity fractionated PLGAs from a single commercially available PLGA (lactide‐to‐glycolide ratio = 50:50). The structural and compositional dependence of properties for pharmaceutical applications in the form of nanofibers and nanoparticles were systematically investigated. The properties of new PLGAs by further separation were significantly dependent on composition. The molecular weight ranges were reduced, while the morphology of nanofibers and nanoparticles became more uniform. Importantly, the stability, mechanical strength, and drug loading increased, and the period of sustained release profile also increased. In brief, our data show that the automated chromatographic separation technique allows for precise control of the molecular weight and lactide‐to‐glycolide composition ratio of PLGA, in contrast to the traditional method. The use of well‐defined and fractionated new PLGA materials holds significant promise for enhancing the potential of PLGA in future pharmaceutical applications. [ABSTRACT FROM AUTHOR]

In this study, methyl/tbutyl salicylate-bearing zirconium complexes (C1–C8) were prepared by the reaction of zirconium (IV) propoxide/butoxide with salicylic acid, 3-methylsalicylic acid, 4-methylsalicylic acid, and 3,5-di-tert-butylsalicylic acid in alcohols, respectively. All these complexes (C1–C8) were characterized by 1H NMR, 13C NMR, FTIR, mass spectroscopy (MS), elemental, and thermogravimetric analyses (TGA). These complexes were utilized as catalysts in the ring-opening polymerization (ROP) of Ɛ-caprolactone and were very effective. Polycaprolactone (PCL) was characterized by 1H-NMR, 13C NMR, and gel permeation chromatography (GPC). In this study, perhaps for the first time, the effects of electron-donating substituents (Me and tBu) on Ɛ-caprolactone polymerization reactions on salicylate ligands linked to zirconium atoms were investigated. [ABSTRACT FROM AUTHOR]

In this study, the simultaneous synthesis of poly(methyl methacrylate-b-ε-caprolactone) block copolymer was fulfilled by atom transfer radical polymerization of methyl methacrylate and ring-opening polymerization of ε-caprolactone. The synthesis of poly(methyl methacrylate-b-ε-caprolactone) block copolymer was carried out by varying the amount of ε-caprolactone monomer, the amount of methyl methacrylate monomer, the amount of 2-(2-chloroethoxy) ethanol initiator, the amount of toluene solvent, and the polymerization time. The effects of these parameters on the reaction conditions were investigated. Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and static light scattering methods were used for the characterization of the synthesized block copolymer. The surface images of the block copolymer were photographed with a scanning electron microscope instrument. In addition, thermal analysis of the synthesized block copolymer was performed using a thermogravimetric analyzer. These analyses prove the formation of the block copolymer structure. The simultaneous synthesis of poly(methyl methacrylate-b-ε-caprolactone) block copolymer was fulfilled by the atom transfer radical polymerization of methyl methacrylate and ring-opening polymerization of ε-caprolactone. The effects of the parameters on the polymerization reaction conditions were investigated. Thermal and spectroscopic measurements prove the formation of the block copolymer structure. [ABSTRACT FROM AUTHOR]

Potassium diphenyl phosphide (KPPh2), which forms a highly nucleophilic phosphide anion, was used as an initiator for the anionic ring-opening polymerization of glycidyl phenyl ether (GPE). GPE was selected as a model compound for the practical application of various glycidyl-type epoxy resins. MALDI-TOF MS analysis of the resulting polymer clarified the presence of a diphenyl phosphine moiety at initiation, confirming that the anionic polymerization was initiated by nucleophilic attack of the phosphide anion on the epoxide. In addition, compared to various basic catalysts such as phosphines and amines, KPPh2 catalyzed the ring-opening addition of epoxide with o-cresol much more efficiently, demonstrating its potential for application to epoxy–phenol curing systems. [ABSTRACT FROM AUTHOR]

Radical polymerization is the most widely applied technique in both industry and fundamental science. However, its major drawback is that it typically yields polymers with non‐functional, non‐degradable all‐carbon backbones—a limitation that radical ring‐opening polymerization (rROP) allows to overcome. The last decade has seen a surge in rROP, primarily focused on creating degradable polymers. This pursuit has resulted in the creation of the first readily degradable materials through radical polymerization. Recent years have witnessed innovations in new monomers that address previous design limitations, such as ring strain and reactivity ratios. Furthermore, advances in integrating rROP with reversible deactivation radical polymerization (RDRP) have facilitated the incorporation of complex, customizable chemical payloads into the main polymer chain. This short review discusses the latest developments in monomer design with a focused analysis of their limitations in a broader historical context. Recently evolving strategies for compatibility of rROP monomers with RDRP are discussed, which are key to precision polymer synthesis. The latest chemistry surveyed expands the horizon beyond mere hydrolytic degradation. Now is the time to explore the chemical potential residing in the previously inaccessible polymer backbone. [ABSTRACT FROM AUTHOR]

Synthesis of monomer‐recyclable polyesters solely from CO2 and bulk olefins holds great potential in significantly reducing CO2 emissions and addressing the issue of plastic pollution. Due to the kinetic disadvantage of direct copolymerization of CO2 and bulk olefins compared to homopolymerization of bulk olefins, considerable research attention has been devoted to synthesis of polyester via the ring‐opening polymerization (ROP) of a six‐membered disubstituted lactone intermediate, 1,2‐ethylidene‐6‐vinyl‐tetrahydro‐2H‐pyran‐2‐one (휹‐L), obtained from telomerization of CO2 and 1,3‐butadiene. However, the conjugate olefin on the six‐membered ring of 휹‐L leads to serious Michael addition side reactions. Thus, the selective ROP of 휹‐L, which can precisely control the repeating unit for the production of polyesters potentially amenable to efficient monomer recycling, remains an unresolved challenge. Herein, the first example of selective ROP of 휹‐L is reported using a combination of organobase and N,N′‐Bis[3,5‐bis(trifluoromethyl)phenyl]urea as the catalytic system. Systematic modifications of the substituent of the urea show that the presence of electron‐deficient 3,5‐bis(trifluoromethyl)‐phenyl groups is the key to the extraordinary selectivity of ring opening over Michael addition. Efficient monomer recovery of oligo(휹‐L) is also achieved under mild catalytic conditions. [ABSTRACT FROM AUTHOR]

Polymers with well‐defined structures, synthesized through metal‐catalyzed processes, and having end groups exhibiting different polarity and reactivity than the backbone, are gaining considerable attention in both scientific and industrial communities. These polymers show potential applications as fundamental building blocks and additives in the creation of innovative functional materials. Investigations are directed toward identifying the most optimal and uncomplicated synthetic approach by employing a combination of living coordination polymerization mediated by rare‐earth metal complexes and C–H bond activation reaction by σ‐bond metathesis. This combination directly yields catalysts with diverse functional groups from a single precursor, enabling the production of terminal‐functionalized polymers without the need for sequential reactions, such as termination reactions. The utilization of this innovative methodology allows for precise control over end‐group functionalities, providing a versatile approach to tailor the properties and applications of the resulting polymers. This perspective discusses the principles, challenges, and potential advancements associated with this synthetic strategy, highlighting its significance in advancing the interface of metalorganic chemistry, polymer chemistry, and materials science. [ABSTRACT FROM AUTHOR]