最新刊期
卷 56 ， 期 9 ， 2025
- 摘要：The unique microphase-separated structure of thermoplastic elastomers endows them with rubber elasticity and remolding ability at high temperatures. Block-type thermoplastic elastomers are the most typical types of thermoplastic elastomers. Due to the diversity of tunable chain structures, the materials exhibit abundant macroscopic properties and wide applications. This article reviews several kinds of industrialized block-type thermoplastic elastomers and the various efforts in improving the heat resistance, chemical resistance, and mechanical properties through the physical modification and chemical modification of hard and soft segments, as well as dynamic covalent cross-linking. This article also describes the shape memory and self-healing functions of thermoplastic elastomers with dual physical and chemical cross-links, as well as the dielectric properties of block-type thermoplastic elastomers, demonstrating their application prospects in high-end fields such as smart electronics and bionic robots. This article further introduces the preparation of bio-based and bio-degradable thermoplastic elastomers, as well as the thermoplastic elastomers from waste or even waste polymers.关键词：Thermoplastic elastomers;Block copolymer;Reversible cross-linking;High-performance;Functionalization687|252|0更新时间：2025-08-28
Review
- 摘要：As a premium polyethylene resin, polyolefin elastomer (POE) demonstrates extensive applications in automotive components, photovoltaic encapsulation films, and wire/cable insulation systems owing to its remarkable impact resistance, superior elasticity, exceptional flexibility, and outstanding compatibility with other polyolefin materials. However, its inherent deficiency in long-chain-branching (LCB) structures results in multiple processing limitations during melt processing, significantly constraining broader industrial implementation. In this study, two strategies were adopted to introduce H-shape LCB structures into the POE molecular chain by employing ω-alkenylmethyldichlorosilane (hex-DCS) and nonconjugated α,ω-diolefin (1,9-DD) as LCB functional additives, respectively. A new type of long-chain-branching polyolefin elastomer (LCB-POE) with both high melt strength, high light transmittance, and significantly enhanced mechanical properties was synthesized. Comprehensive characterization including Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and melt rheological analysis conclusively demonstrated the successful incorporation of LCB structures, with the degree of LCB increasing proportionally to the concentration of LCB agents. Comparative rheological analysis revealed distinct structural evolution pathways: non-conjugated α,ω-diolefins as LCB agents initially induced pendant short-chain branches on POE backbones at low concentrations, failing to transition into LCB architectures. In contrast, ω-alkenylmethyldichlorosilane exhibited superior LCB formation efficiency, achieving effective long-chain branching at equivalent low loading levels through optimized topological connectivity.关键词：ω-Alkenylmethyldichlorosilane;Nonconjugated α;ω-diolefin;Long-chain-branching structures;Constrained geometry catalyst;Polyolefin elastomer241|110|0更新时间：2025-08-28
- 摘要：The strategy of remote bulky group substitution in modifying polyolefin catalysts has the potential to modulate catalytic behavior, a facet often overlooked in coordination insertion olefin polymerization reactions. In this study, a series of para-trityl substituted α-diimine nickel catalysts Ni1-Ni5 with different steric hindrances were synthesized and characterized. Upon activation with diethylaluminum chloride (Et2AlCl), all Ni(II) catalysts were employed for ethylene chain-walking polymerization and the effects of spatial steric hindrance were investigated. The research indicates that the introduction of trityl groups at the para-position can form remote rigid steric hindrance, thereby significantly enhancing the thermal stability of the nickel catalysts and exhibiting outstanding catalytic performance. The spatial steric effects of the catalysts, as well as changes in polymerization conditions, have a significant impact on ethylene polymerization activity, the molecular weight of the resulting polyethylene, branching degree, thermodynamic properties, and mechanical properties. The isopropyl-substituted Ni3-Ni5 exhibited extremely high catalytic activities of up to 1.26×107 g·mol-1·h-1 toward ethylene polymerization producing high molecular weight branched polyethylene, while maintaining excellent mechanical and elastic properties. Notably, even at a higher polymerization temperature of 120 ℃, the asymmetric structure of Ni5 still maintained high activity of up to 8.10×106 g‧mol-1‧h-1.关键词：Nickel catalyst;Ethylene polymerization;Chain walking;Polyolefin elastomers63|15|0更新时间：2025-08-28
- 摘要：Nickel(II) α-diimine complexes have attracted significant attention due to their unique "chain-walking" polymerization mechanism, which enables in situ regulation of branching density and branching type in polymer backbone, and have been widely investigated for polyolefin elastomer (POE) synthesis. In this work, a series of symmetric/asymmetric α-diimine nickel catalysts based on electronic and steric synergistic effects were synthesized and applied in ethylene polymerization. By introducing methoxy groups at the 3,4,5-positions of the aniline moiety, these substituents not only exhibit electron-donating effects, but also generate steric repulsion with 2,6-position substituents, thereby pushing axial steric groups close to the active center for effectively shielding the central metal. The 3,4,5-trimethoxy substitution strategy combining electronic and steric effects significantly promotes chain propagation while suppressing chain transfer reactions. These catalysts generally demonstrate high catalytic activities (up to 1.1×108 g·mol-1·h-1), producing polyethylene elastomers with tunable molecular weights (Mn=124-2106 kDa) and tunable branching densities (41-103 branches/1000C). High-temperature 13C-NMR analysis reveals that the polymer microstructure is dominated by methyl branches, with around 20% of short-chain branches (ethyl, n-propyl, n-butyl, etc.) in total branches. Tensile testing of polyethylene samples with different molecular weights and branching densities show that these highly branched polyethylenes exhibit low-to-moderate tensile strength (2.16-12.33 MPa) and high elongation at break (339%-1339%), indicating excellent toughness. These polyethylene materials generally demonstrate favorable elastic recovery properties, achieving a maximum strain recovery of 91%.关键词：Polyolefin;α-Diimine Ni(II) catalyst;Synergy;Ethylene polymerization;Polyethylene elastomer199|32|0更新时间：2025-08-28
- 摘要：With the continuous development of marine resources, metal corrosion has become a critical issue affecting the normal operation of equipment underwater, and it holds significant strategic importance for the long-term protection of offshore equipment. Self-healing coatings can autonomously repair damage and prevent the intrusion of corrosive media, providing long-lasting corrosion protection. Inspired by the mussel proteins in the ocean, a self-reporting and self-healing elastic biomimetic coating material, LP55-BPY, was designed based on dynamic disulfide bonds. Experimental results showed that LP55-BPY exhibits excellent mechanical properties, with a Young's modulus of 1.74 MPa and a puncture resistance of 976 mJ. The dynamic exchange of disulfide bonds in the main chain and the saturated structure endowed the material with good self-healing performance and resistance to solvent, with a healing efficiency of 92% after 5 h at room temperature. After damage, the bipyridyl groups in LP55-BPY could capture Fe3+ ions in the underwater environment, and the coordination crosslinking at the damaged site imparts self-coloring reporting and self-enhancing properties to the coating, facilitating wound repair. Additionally, LP55-BPY also demonstrated good recyclability and could be used for surface corrosion protection of offshore equipment.关键词：Self-reporting;Self-healing;Coating materials;Coordinate bond;Disulfide bond216|265|0更新时间：2025-08-28
- 摘要：Lewis bases are frequently employed as polar modifiers to enhance the 1,2-selectivity of butadiene anionic polymerization. In this work, we report four novel N,O-bidentate Lewis bases bearing different alkyl substituents: 1-(2-methoxyethyl)piperidine (MOD 1), 1-(2-ethoxyethyl)piperidine (MOD 2), 1-(2-propoxyethyl)piperidine (MOD 3), and 1-(2-butoxyethyl)piperidine (MOD 4). A comparative study was conducted between these newly synthesized polar modifiers and five commonly used, previously reported modifiers, focusing on their effects on the anionic polymerization of butadiene. Additionally, we investigated how the dosage of various modifiers and the polymerization temperature influence the polymerization behavior. The results show that the newly designed N,O-bidentate polar modifiers can achieve a high degree of 1,2-structural regulation in polybutadiene at relatively low dosage levels. Their regulatory effectiveness remains stable across different polymerization temperatures, demonstrating both high efficiency and excellent stability.关键词：Anionic polymerization;Polar modifiers;Butadiene;Microstructure128|225|0更新时间：2025-08-28
- 摘要：Thermoplastic polyurethane (TPU) has become a pivotal engineering material due to its unique combination of elasticity and processability. Recent research has focused on elucidating the structure-property relationship to guide high-performance TPU design. This study innovatively explores the impact of segment sequence length on material performance through a systematic synthesis strategy. Using pre-polymerization and chain extension techniques, we developed a series of hydrazide-based TPU elastomers with identical hard/soft segment ratios but varying sequence lengths. Characterization results reveal that extending the sequence lengths induces two critical structural modifications: enhanced microphase separation between hard and soft domains, and optimized hierarchical hydrogen bonding networks. These structural changes collectively elevate material performance, with long-sequence TPUs exhibiting a 50% increase in tensile strength (from 50 MPa to 80 MPa), and significantly higher flow temperatures (ΔT>45 ℃) compared to short-sequence counterparts. Notably, stress relaxation tests demonstrate that extended sequences increase the relaxation time significantly, indicating superior dimensional stability. The performance enhancements stem from the dual reinforcement mechanism: microphase separation creates robust physical crosslinks while hierarchical hydrogen bonds enable energy dissipation. This sequence engineering approach provides a paradigm shift from traditional composition-focused design to topological structure optimization, offering a viable pathway for developing TPUs that simultaneously satisfy conflicting requirements of mechanical robustness and processing efficiency in industrial applications.关键词：Thermoplastic polyurethane;Elastomer;Sequence length;Hydrogen bond;Mechanical properties276|340|0更新时间：2025-08-28
- 摘要：In recent years, thermoset polyurethane materials that can be remolded by introducing dynamic covalent bonds have received much attention. However, most dynamic polyurethanes are solution polymerized. The use of solvents complicates the process and increases the cost. In this study, a dynamic polyurea elastomer containing hindered urea bonds was prepared by solvent-free polymerization of an industrially produced secondary amine-type chain extender with isophorone diisocyanate (IPDI) and polytetrahydrofuran diol (PTMG). The raw materials are cheap and easy to obtain, and the preparation process is green and environmentally friendly, which has a good prospect for industrialized production. The structure and properties of the elastomer were characterized by infrared spectroscopy, ultraviolet spectroscopy, dynamic thermo-mechanical analysis, thermogravimetric analysis and rheological test. The results show that the polyurea elastomers containing hindered urea bonds have good mechanical properties (tensile strength: 13.0-24.5 MPa), excellent resilience and reprocessability. In addition, we further explored the potential applications of the prepared polyurea elastomers by utilizing them to prepare a triboelectric nanogenerator (TENG), demonstrating its potential for electrical applications.关键词：Hindered urea bonds;Polyurea elastomers;Reprocessable;Triboelectric nanogenerators340|172|0更新时间：2025-08-28
- 摘要：In this study, polycaprolactone (PCL) was used as the soft segment, and two kinds of thermoplastic polyurethane elastomers (TPU-IM and TPU-IS) with different stereoconfigurations were constructed by introducing chiral diols isosorbide (IS) and isomannide (IM), revealing the influence of the molecular conformation of the chain extender on the properties of the materials. The study found that the TPU-IM system forms a higher density of hydrogen bond cross-linking network due to its rigid three-dimensional conformation, and the hydrogen bond content increases linearly with the increase of the hard segment ratio. In terms of mechanical properties, TPU-IM-30 exhibits high comprehensive properties with a tensile strength of 71.0 MPa and an elongation at break of 1312%. Its Young's modulus (45.3 MPa) is 125% higher than that of the corresponding TPU-IS-30. Moreover, compared with TPU-IM-20, the increase in the hard segment content does not significantly sacrifice the elongation at break. The cyclic tensile test shows that TPU-IM-30 exhibits higher resilience and excellent energy dissipation ability than TPU-IS-30 under low strain. Meanwhile, both TPU-IM and TPU-IS elastomers possess tear resistance, stress relaxation resistance, thermal stability, and reprocessability. This study reveals the unique advantages of the stereoconfiguration of isomannide in constructing a dynamic hydrogen bond network, providing new ideas for the design of intelligent responsive materials with high strength, high toughness, and energy dissipation capabilities.关键词：Stereoisomer;Hydrogen-bonding Structure;Thermoplastic polyurethane;High-performance Elastomer189|168|0更新时间：2025-08-28
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The Effects of Stacking Process on Microstructure and Properties of Natural Rubber and Its Mechanism
摘要：Natural rubber (NR) has become a crucial strategic resource due to its exceptional comprehensive properties. However, the batch-to-batch stability issues in production have constrainedits industrial-scale development and practical applications. Although stacking treatment of raw NR can partially improve batch stability, the microstructural changes during stacking and their impacts on performance remain unclear, which hinders the industrial application of this technique. The study investigated the structural changes of NR during stacking using Kjeldahl nitrogen determination and Fourier transform infrared spectroscopy (FTIR). The effects of stacking on NR properties were systematically evaluated through rheological behavior analysis, processing performance testing, vulcanization characterization, and mechanical property measurements. The results demonstrate that stacking treatment increases protein content while reducing lipid content in NR. The elevated protein content enhances the curing rate and energy dissipation capacity of vulcanizates, along with improved resistance to thermo-oxidative aging. Conversely, lipid reduction decreases gel content, leading to diminished mechanical properties and storage modulus. Nevertheless, reduced gel content promotes homogenization of the network structure, thereby enhancing storage modulus at elevated temperatures and ultimately improving the mechanical performance of vulcanizates. This work elucidates the structural evolution mechanism of NR during stacking and its correlation with performance variations, providing a theoretical foundation for implementing stacking technology in NR industrial production.关键词：Natural rubber;Stacking pretreatment;Native network;Non-rubber components;Structure-property relationship152|106|0更新时间：2025-08-28 - 摘要：The solid-state polymerization (SSP) of polyamide 66 (PA66) is a critical method for adjusting its macromolecular weight and mechanical properties. In this study, one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy (NMR) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to analyze the chemical structures of the by-products in the PA66 pellets before and after SPP. By integrating techniques such as end-group titration and liquid chromatography-mass spectrometry (LC-MS), this study elucidates the patterns of the macromolecular weight increase during the SSP process and identifies the types of by-products. Methanol extraction experiments indicated that SSP could also lead to a decrease in the cyclic PA66 content, particularly a notable reduction in cyclic PA66 with repeat unit numbers from 1 to 4. Considering the difficulty in effectively separating various by-products present in PA66 pellets, the spectroscopic characterization methods in this research could identify their signals within the complex NMR and MS spectra. This approach promises to establish a foundation for quantitatively calculating the by-product content, thereby supporting the optimization of the PA66 polymerization and SPP processes and enhancing the quality of PA66 pellets.关键词：PA66;Solid-state polymerization;Nuclear magnetic resonance spectroscopy;Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry;Cyclic by-product303|189|0更新时间：2025-08-28
- 摘要：Cellulose nanocrystals (CNCs) derived from natural sources were incorporated to reinforce polydimethylsiloxane (PDMS), which not only enhanced the mechanical strength but also imparted a degree of biocompatibility to the composite, aligning with the principles of sustainable development. However, the poor compatibility between CNCs and PDMS makes it difficult for CNCs to disperse uniformly within the matrix. Silanization grafting modification of CNCs is an effective way to improve their compatibility with PDMS. To prevent the self-polymerization of silane coupling agents during the grafting process, this study utilized the carboxyl groups on carboxylated cellulose nanocrystals (CCA) to react with the amino groups of 3-aminopropyltriethoxysilane (KH550) via amidation, thereby producing cellulose nanocrystals with high silane groups (CCK). The silane groups on CCK can participate in the crosslinking reaction with PDMS, forming covalent interactions between the two, which promotes the uniform dispersion of CCK in the PDMS matrix. CCK exhibits dual functions of reinforcement and crosslinking, significantly improving the mechanical properties of PDMS/CCK composites. Furthermore, compared to pure PDMS, the PDMS/CCK composites demonstrate enhanced thermal stability.关键词：carboxylated cellulose nanocrystals;Amidation modification;Polydimethylsiloxane;Cross-linking184|155|0更新时间：2025-08-28
- 摘要：Unsaturated polyester resins have excellent properties after curing, but suffer from inherent brittleness and poor toughness, which requires toughening modification. Block copolymers can be used for toughening modification of unsaturated polyester resins, but the effect of block number and block segmental length on the mechanical properties has rarely been reported. In this study, poly(ether ester) multiblock copolymers (mBCPs) were used as toughening modifiers, and the effects of their structure, such as block number and segmental length, on the properties of the cured unsaturated polyester resins were investigated. A series of (PEB-b-PTMO-b-PEB)n mBCPs with different block numbers, i.e., total molecular weights and block segment length, were synthesized via a cascade polycondensation-coupling ring-opening polymerization using ethylene brassylate (EB) and poly(tetramethylene oxide) (PTMO) diols with different molecular weights as monomers. The modified cured unsaturated polyester resins were prepared by mixing the mBCPs with unsaturated polyester resins, adding an initiator, and subsequently heating to induce crosslinking. The results indicate that the addition of a small amount of mBCPs (1 wt%-5 wt%) can significantly enhance the tensile strength, Young's modulus, notched impact strength, and toughness of the cured resins, up to 48%, 31%, 20%, and 178%, respectively. With other factors held constant, the strength, elongation at break, and toughness of the cured resins increased with the addition amount of mBCPs or block number, while the notched impact strength did not change much, and modulus decreased slightly. Additionally, the strength, modulus, and toughness of the cured resins increased slightly with the increment of segmental length. The above results demonstrate that mBCPs exhibit significant advantages over diblock or triblock copolymers in toughening modification, providing a novel approach for the property modification of unsaturated polyester resins.关键词：Block copolymer;Unsaturated polyester resin;Toughening;Strengthening125|104|0更新时间：2025-08-28
- 摘要：The introduction of dynamic covalent bonds (DCBs) into polyurethane to form a vitrimer is an important method for sustainably developing polyurethane materials. Polyurethane vitrimer has the advantages of good mechanical and thermal properties, such as thermosets, and good malleability for thermoplastics. They have unique stress-relaxation behaviors that satisfy the Arrhenius equation at a given temperature window. It is interesting to know how the activation energy correlates with the types and contents of DCBs, as well as the spline preparation and measurement settings. Here, based on 61 splines with reported activation energy associated with stress relaxation (Ea), glass transition temperatures (Tg), partially with the topology freezing transition temperature (Tv), and the temperature windows, we built regression models for Ea using CatBoost and SISSO algorithms, respectively. They provided a determination coefficient of 0.998 for the CatBoost-based implicit model and 0.837 for the SISSO-based explicit model. Globally, Ea is positively correlated with the temperature window that satisfies the Arrhenius equation and the polymerization temperature and negatively correlated with Tg and the initial constant strain rate. Based on the current dataset, Ea shows a weak dependence on the DCB types and their fractions in the explicit model. Overall, this study attempted to quantitatively understand the unique properties of polyurethane vitrimers, and the regression models confirmed the feasibility, while further accumulation of data and a deeper understanding of the stress-relaxation behaviors of polyurethane vitrimers are still required.关键词：Polyurethane;Vitrimer;Dynamic covalent bonds;Activation energy;big data122|167|0更新时间：2025-08-28
- 摘要：Butadiene polymerization mediated by neodymium-based catalytic system with characteristics of controllable coordination chain transfer polymerization (CCTP) is reported herein. Due to the inherent nature of rapid and reversible chain transfer during the BD polymerization, polymer-Al bonds were able to be generated during the end of the polymerization, allowing amide groups inserting efficiently in to the ω-end of the polymer chain, and thus achieving in situ functionalization of high molecular weight cis-polybutadiene rubber. The structure of the polymer was well characterized by GPC, FTIR and DSC. It was demonstrated that the introduction of amide groups led to the formation of hydrogen bonding interactions between the polymer chains. When comparing with the unfunctionalized counterpart, both the surface energy and Mooney viscosity were significantly increased. More importantly, significantly improved dispersity of fillers was demonstrated, which further resulted in enhanced crosslink density, tensile strength (from 19.6 MPa to 22.2 MPa) and toughness of the vulcanizate. Overall, this study provides a simple and efficient strategy for the in situ functionalization of high molecular weight cis-polybutadiene rubber while maintaining the high cis-1,4 content and high regularity of the mainchain, showing a great potential for large-scale industrialization.关键词：Coordination chain transfer polymerization;Rare earth catalyst;Butadiene;Functionalization130|131|0更新时间：2025-08-28
- 摘要：Cholesteric liquid crystal elastomers (CLCEs) have attracted considerable attention in smart actuators and sensors due to their exceptional elasticity, unique helical photonic-crystal architectures, and highly sensitive stimulus-response deformations behevior. However, realizing synchronous shape and color change over a wide wavelength range under mild thermal stimuli remains a major challenge. In this study, a dynamic side-chain CLCE was constructed via thiol-ene click chemistry, using flexible polymethylmethylsiloxane (PMMS) as backbone, in combination with monofunctional liquid‐crystal mesogens, and bifunctional rigid/soft crosslinkers. A high density of mesogenic motif was grafted onto the flexible PMMS backbone as side-chains, effectively lowering the phase-transition temperature of network; concurrently, the introduction of dynamic disulfide bonds endows the material with topological adaptability. The resulting CLCEs exhibited outstanding thermochromic and mechanochromic responses within the temperature range of 25-80 ℃, with mechanochromic shifts exceeding 160 nm across the visible spectrum. The representative sample demonstrated prominent simultaneous deformation and color-change behavior, confirming the potential of this material system in adaptive and intelligent soft devices.关键词：Chiral liquid crystalline elastomers;Thermochromism;Mechanochromism;Shape memory;Disulfide bond224|117|0更新时间：2025-08-28
Research Article
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