Chinese Journal of Polymer Science最新文献

Poly(vinyl chloride) (PVC) materials are produced with high smoke and toxic gases during combustion, when commercial flame-retardant additives are incorporated. Here, rare-earth yttrium stannate (Y₂Sn₂O₇), which is superior to commercial flame retardants, was designed to enhance the smoke suppression and toxicity reduction performance of PVC materials without damaging their mechanical properties. After the addition of 15 wt% Y₂Sn₂O₇ (PVC/Y₂Sn₂O₇), the PVC composites achieved a V-0 rating, whereas the pure PVC material achieved a V-2 rating. The peak heat release rate of PVC/Y₂Sn₂O₇ composite was reduced from 282.7 kW/m² (pure PVC) to 243.6 kW/m². In addition, the maximum smoke density (Ds-max) of PVC/Y₂Sn₂O₇ was 263 m²/m², a decrease of 48.5% compared to pure PVC materials (511 m²/m²), indicating its outstanding ability for smoke suppression. Compared to Sb₂O₃, Y₂Sn₂O₇ can effectively reduce the release of the toxic gas CO (decreasing by 37.5%). Furthermore, the tensile strength of PVC can reach as high as 16.1 MPa. Compared with five widely used commercial flame retardants, Y₂Sn₂O₇ demonstrates superior performance, positioning it as a promising alternative to prospective candidates. Therefore, this study developed a rare-earth flame retardant and offers a promising design to improve the fire safety of PVC composites.

Polymers that exhibit both biodegradability and chemical recyclability offer a promising solution to environmental pollution and resource scarcity. Poly(glycolic acid) (PGA) is a promising chemically recyclable polymer, characterized by its seawater degradability and high mechanical strength. In this study, aliphatic polycarbonates were synthesized through melt polycondensation and subsequently copolymerized with glycolide (GL) to produce chemically recyclable PGA based triblock copolymers with well-defined structures. The properties of these copolymers, including their thermal properties, crystallization behavior, and mechanical performance, can be effectively adjusted by modifying the structure and content of the middle block. Furthermore, an in-depth investigation reveals that the pyrolysis process involves ester exchange, radical, and back-biting reactions. In addition, the high-efficiency “Monomer↔Copolymer” chemical recycling loop has been established, achieving a remarkable yield exceeding 88% along with a purity greater than 99%.

An efficient, simple, and convenient method for Suzuki polycondensation using a diaminocarbene palladium(II) catalyst under aerobic conditions was developed. Reactions between aromatic diboronic acid bis(pinacol) ester and different aromatic dibromides, both with electron-donating and electron-withdrawing fragments in the structure, were carried out. Various reaction conditions, such as the effect of catalyst concentration and solvent, were investigated. The molecular weight characteristics, photo- and electroluminescence properties of the synthesized polymers were studied.

The aim of this study is to develop magnetopolymer composites suitable for fabricating soft magnetoactive robots via extrusion-based 3D printing. Polysiloxane copolymers with urea fragments were synthesized and characterized, and their thermophysical and rheological properties were investigated. This study provides an assessment of the potential for their further use in additive manufacturing. The obtained materials were utilized as matrices for creating magnetically active polymer composites by incorporating microparticles of carbonyl iron. Samples of complex geometries were printed using both neat and filled filaments, demonstrating the feasibility of employing these materials in extrusion-based 3D printing.

Herein, we reported a Tb-carboxyl-imidazole coordination-crosslinked carboxylated nitrile butadiene rubber (XNBR) elastomer design that exhibits high mechanical robustness, fluorochromism, and white-light emission. Imidazole (Im), a toughening, sensitizing, and self-emissive ligand, highly intensified the fluorescence emission, remarkably toughened the elastomer, and imparted multistimuli responsiveness to the elastomer. The Tb³⁺ ions acted as cross-linking centers and provided high-temperature sensitivity of fluorescence emission (more sensitive than Eu³⁺ ions). The as-prepared XNBR/Tb/Im elastomer, with excellent puncture resistance, exhibited an ultimate extensibility of about 3100% and the highest tensile strength of 22 MPa. Experimental and theoretical investigations have demonstrated that Tb³⁺ ions are more likely to interact with Im ligands with increasing amounts of Im. The number of coordination cross-links with higher cross-linking functionalities showed an increasing trend during stretching. The elastomer exhibited an excitation wavelength and temperature-dependent green emission. By introducing redemissive Eu³⁺ into the elastomer, a white-light-emitting XNBR/Tb/Eu/Im elastomer with chemo-fluorochromism was fabricated. The XNBR/Tb/Eu/Im elastomer exhibited stable white-light emission during both heating and stretching. Changing the temperature only resulted in a variation in the intensity of the white light. We demonstrated the potential applications of these elastomers in patterning and information anticounterfeiting/encryption. This coordination crosslinked tough elastomer with fluorochromism and white-light emission paves a new way to fabricate soft devices and sensors, where optical information displays and optical signal responses are required.

The low-voltage plateau capacity, which is highly related to the internal closed pores in hard carbon (HC), is the main contributor to the total capacity in sodium-ion batteries. However, the formation mechanism of closed pores and modification strategies at the molecular level in HC polymer precursors remain poorly understood. Furthermore, the practical applications of HCs are significantly impeded by their low initial coulombic efficiency (ICE). In this study, the intramolecular heteroatom doping (IHP) effect was proposed to facilitate the formation of closed pores in polymer-derived HC for the first time by grafting sulfonyl, ether, and carbonyl groups between benzene rings. As a result, the optimized HC sample showed an increased closed pore volume and low Na⁺ adsorption energy, which delivered a reversible capacity of 307.9 mAh·g⁻¹ and superior rate capability. Through further optimized presodiation, the formed presodiated HC featuring a thin, smooth, and dense solid electrolyte interface film exhibited a remarkably enhanced ICE of 94.4% and enhanced cycling stability (93.6% over 3000 cycles). This study provides an in-depth understanding of the formation mechanisms of closed pores via IHP engineering and develops a new synergistic strategy involving presodiation to prepare highly stable HC anodes.

The poor degradability and limited recyclability of epoxy resins are key challenges hindering the efficient recycling of ex-service wind turbine blades (EWTBs). Herein, we proposed a selective degradation strategy for direct recycling and high-value recovery of epoxy resins by introducing degradable Schiff base groups into the molecular structure and utilizing the resulting oligomers as curing agents. To realize this strategy, a series of Schiff base compounds were synthesized using bio-based vanillin and diamines and subsequently functionalized with epichlorohydrin to yield bio-based epoxy resins. The cured epoxy resins demonstrated remarkable improvements in the mechanical properties of diglycidyl ether of bisphenol-A (DGEBA), with an increases of 44.49% in the tensile strength of 38.55%, bending strength, and impact strength of 71.20 %. The introduction of dynamic Schiff base bonds enabled the selective degradation of the vanillin-2,2-bis[4-(4-aminophenoxy)phenyl] propane-based epoxy resin (VBEP)/DGEBA copolymer, producing 84.20% oligomers that can be directly recycled and reused. Replacing 30 wt% of the curing agent with the oligomer increased the tensile strength of the cured sample to 75.40 MPa, surpassing that of the cured DGEBA. Under simulated acid rain and seawater exposure, the copolymer exhibited a service life of 27 years at 40 °C, significantly exceeding the currently reported service life of 20 years. This study presents a sustainable strategy for the direct recycling and high-value reuse of epoxy resin, offering a promising solution for EWTBs.

Thermophilic proteins maintain their structure and function at high temperatures, making them widely useful in industrial applications. Due to the complexity of experimental measurements, predicting the melting temperature (T_m) of proteins has become a research hotspot. Previous methods rely on amino acid composition, physicochemical properties of proteins, and the optimal growth temperature (OGT) of hosts for T_m prediction. However, their performance in predicting T_m values for thermophilic proteins (T_m>60 °C) are generally unsatisfactory due to data scarcity. Herein, we introduce TmPred, a T_m prediction model for thermophilic proteins, that combines protein language model, graph convolutional network and Graphormer module. For performance evaluation, TmPred achieves a root mean square error (RMSE) of 5.48 °C, a pearson correlation coefficient (P) of 0.784, and a coefficient of determination (R²) of 0.613, representing improvements of 19%, 15%, and 32%, respectively, compared to the state-of-the-art predictive models like DeepTM. Furthermore, TmPred demonstrated strong generalization capability on independent blind test datasets. Overall, TmPred provides an effective tool for the mining and modification of thermophilic proteins by leveraging deep learning.

Adjusting the structure of the hard segment (HS) represents a key method for manipulating the mechanical properties of thermoplastic polyurethane (TPU). This study developed a novel molecular design strategy to tailor TPU’s mechanical performance through altering the terminal diisocyanate structure of HS. The typical HDI-BDO based TPU was chosen as a model. Replacing HS’s terminal HDI residues with aromatic PPDI, TODI, and MDI (the corresponding TPUs are named as 2P, 2TO, and 2M, respectively) enabled broad tuning of TPU’s Young’s modulus while maintaining high tensile strength and elongation. Compared with linear PPDI and TODI, the bent and unsymmetrical MDI exhibits greater deviation from the central axis of the middle HDI-BDO segment, which reduces HS’s capability of three-dimensionally ordered packing. Therefore, 2P and 2TO show higher hydrogen bond content and crystallinity, stronger physical crosslinking network, and thus much higher Young’s modulus than 2M (75.6 MPa). Besides geometric structure, π–π stacking between HS’s terminal aromatic diisocyanates critically governs TPU’s physical crosslinking network. In 2P, π–π stacking induces torsion of the middle HDI-BDO segment and disrupts the neighboring hydrogen bonds, leading to a dense network with fine hard blocks. In contrast, the lateral methyl groups in TODI hinder π–π stacking, resulting in a sparse network with large hard blocks. Accordingly, 2TO exhibits a higher Young’s modulus (146.2 MPa) than 2P (124.0 MPa), but greater strain-rate sensitivity.

This study reports the fabrication of polypropylene (PP)-based microfiber webs (<1 µm) using a hybrid melt electrospinning/blown process with the aim of establishing a scalable and solvent-free platform for advanced lithium-ion battery separators. The primary objective was to address the inherent limitations of conventional melt electrospinning particularly the difficulty of achieving fiber thinning due to the high viscosity of polymer melts by incorporating auxiliary hot air flow and reducing the nozzle diameter from 1.0 mm to 0.3 mm. This modified configuration enables enhanced jet elongation and fiber diameter control under processing conditions relevant to industrial applications. The effects of nozzle temperature, hot air temperature, and applied voltage on fiber formation and jet behavior were systematically examined using highspeed charge-coupled device (CCD) imaging techniques. The results demonstrated that increasing both the hot air temperature and applied voltage significantly improved fiber thinning and uniformity, yielding an average fiber diameter of approximately 0.86 µm without evidence of thermal degradation. In contrast, elevated nozzle temperatures, while enhancing melt flowability, resulted in increased discharge rates and hindered fiber refinement when applied alone. These findings identify hot-air temperature as the most robust and controllable parameter for producing submicron fibers while maintaining the polymer integrity. Although the present study primarily focuses on morphological optimization and jet dynamics, future research will investigate the functional performance of fabricated microfiber webs as battery separators. Overall, the proposed hybrid process offers a technically feasible and environmentally sustainable route for the continuous production of fine PP-based fibers tailored for high-performance energy-storage applications.