最新刊期
卷 56 ， 期 4 ， 2025
- 摘要：Establishing the intrinsic relationship among crystal structure, molecular packing, and photovoltaic performance is crucial for advancing non-fused ring electron acceptor (NFREA) materials, while dipole moment serves as one of the key factors in regulating molecular packing. In this work, based on the large dipole 3-cyanothiophene building block, a series of asymmetric NFREAs (X4, X5, and X6) were developed, for which the impacts of varied terminal groups on the molecular optoelectronic properties and photovoltaic performance were systematically investigated. The strong electron-withdrawing ability of the cyano-group significantly weakens the electron-donating effect of the thiophene unit, resulting in relatively deep HOMO levels for the acceptors, thus enabling favorable energy level alignment with the donor PM6. Single-crystal analysis revealed that the strong dipole moment at the molecular core drives the dimer formed in face-to-face arrangement, while variations in terminal groups alter the stacking arrangements between dimers. Specifically, the fluorinated X4 adopts J-aggregation packing between dimers, while the chlorinated X5 tends to the co-existence of H-aggregation and J-aggregation packing between dimers. Ultimately, organic solar cells based on X6, which bears larger conjugated terminal groups, achieved a short-circuit current density (JSC) of 19.90 mA·cm-2, a fill factor (FF) of 72.38%, and a power conversion efficiency (PCE) of 12.05%, outperforming those based on X4 (11.81%) and X5 (11.87%).关键词：Organic solar cell;Asymmetric;Non-fused ring acceptor;3-Cyanothiophene;Single crystal structure262|153|0更新时间：2025-04-01
- 摘要：Traditional polyurethane thermosets with highly cross-linked structure are unable to flow and be reprocessed, raising recycling challenges and environmental concerns. Here, a closed-loop chemical recycling approach was proposed for thermoset polyurethane elastomers. Based on the fundamental principles of chemical equilibrium and reversibility of urethane-bond formation, we designed a reversible exchange pathway between linear precursor and cross-linked polyurethane (C-PU) by controlling the concentration of side product, i.e., n-butanol, which can facilitate the transformation between the crosslinked network and linear counterpart. The recycled elastomer retained good elastomeric properties and showed comparable mechanical performance as its pristine sample. The Fourier transform infrared spectroscopy and nuclear magnetic resonance analysis confirmed the structural consistency of elastomers before and after chemical recycling, validating the effectiveness of the closed-loop recycling strategy. In addition to chemical recycling, the C-PU can also be reprocessed by direct thermal treatment of fractured or damaged material, which meets the requirements for various applications. This study opens a new avenue for closed-loop cycling of polyurethane thermosets and sustainable utilization of other thermosetting polymer materials.关键词：Polyurethane Thermosets;Dynamic bond;Closed-loop Recycling;Chemical Equilibrium353|170|0更新时间：2025-04-01
- 摘要：Two kinds of blue narrowband emissive polymers (P1-01-P1-05 and P2-01-P2-05) are designed and synthesized using non-conjugated polyethylene as backbone, boron, sulfur, nitrogen-doped polycyclic aromatic hydrocarbons (5-sulfur-8b-borobenzo[a]naphthano[1,2,3-hi]anthracene, Ph-BSCz) as emitter, and carbazole and N-phenyl-3,6-di-t-butylcarbazole with hole-transporting ability as host units. The multi-resonance effect of boron, sulfur, nitrogen-doped polycyclic aromatic hydrocarbon enables the polymers to exhibit blue narrowband emission (λem of 473-483 nm and FWHM of 31-39 nm), and enhances spin-orbit coupling by heave-atom effect of sulfur to improve reverse intersystem crossing rate from triplet to singlet state. On the other hand, compared to polymers (P1-01~P1-05) bearing carbazole units, polymers (P2-01-P2-05) containing N-phenyl-3,6-di-t-butylcarbazole units have higher HOMO energy levels and lower hole injection barriers. Solution-processed OLEDs based on P2-03 bearing N-phenyl-3,6-di-t-butylcarbazole units and 3 mol% emitters exhibit the best electroluminescence performance, with emission peak at 481 nm, FWHM of 31 nm, maximum external quantum efficiency of 8.0%, and power efficiency of 8.1 lm/W.关键词：Boron;Sulfur;Nitrogen-doped polycyclic aromatics;Narrowband emission;Blue emission276|72|0更新时间：2025-04-01
- 摘要：Dendrimer is a type of three-dimensional and spherical unimolecular nanomaterials with highly branched and precise architecture, while the rapid and efficient synthesis of high-generation dendrimer has been challenging in the field of polymer chemistry. Herein, we reported a new approach for the rapid and efficient preparation of dendrimers by using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) with reaction-enhanced reactivity of intermediates (RERI) mechanism. In this approach, two multi-azide functionalized molecules (C-9N3 and C-27N3) with 1,3-triazide terminal groups and a series of dendrons with alkynyl focal point (ay-dendron) were first synthesized as the core and shell, respectively, for preparing core-shell dendrimers via a convergent strategy. The C-9N3 and C-27N3 molecules with 1,3-triazide structure are capable of RERI effect, which could greatly overcome the steric effect and allow the quantitative coverage of the azide groups in the presence of a slight excess of ay-dendron (1.2 eq.). The kinetics indicated that the CuAAC reaction could finish in minutes, promoting the preparation of a series of 4-7 generation core-shell dendrimers with ultrafast rates. The chemical composition, molecular structure, morphology and size of the resultant core-shell dendrimers were systematically characterized by nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS), dynamic light scattering (DLS) and atomic force microscopy (AFM). This approach can be not only used for the ultrafast preparation of dendrimers with precise architectures, but also beneficial for the structural regulation and functionalization of dendrimers by tailoring the chemical structures of the "core" and "shell".关键词：Dendrimer;Copper-catalyzed azide-alkyne cycloaddition;Reaction-enhanced reactivity of intermediates;Convergent approach371|137|0更新时间：2025-04-01
- 摘要：Recently, photonic crystals and their composite films have attracted much attention due to their unique optical properties and promising applications in optical sensors, optical communication, anti-counterfeiting techniques and so on. Photonic crystal-polymer composite films with multimodal responsiveness are highly desirable yet still limited. In this work, a new kind of inverse opal composite polymer films responsive to both solvent and light has been successfully prepared, by copolymerizing azobenzene (AzoMMA) with different hydrophilic/hydrophobic acrylic monomers (butyl methacrylate (BMA), poly(ethylene glycol) acrylate (PEGDA)) and cross-linking agent (ethoxylated trimethylolpropane triacrylate (ETPTA)) and using structural colored photonic crystals as the template. The optimal composition of the polymers is determined (AzoMMA:PEGDA:BMA:ETPTA = 1:4:8:1, molar ratio) according to the reflection spectra and contact angle testing. Wideband visible light reflection is achieved for films that are obtained by using silica photonic crystals with different diameters and in different solvents. This composite film with dual responsive properties can be used to store information under ultraviolet light irradiation, encrypt patterns in its dry state, and decrypt the information quickly and with a high-contrast visual effect in solvents. This material is thus expected to be applied in high-level anti-counterfeiting, encryption storage of information, sensing and other fields.关键词：Azobenzene;Inverse opal;Dual responsive;Photonic crystal;Anti-counterfeiting encryption132|146|0更新时间：2025-04-01
- 摘要：Conjugated microporous polymers (CMPs) exhibit high potential in the field of iodine adsorption due to their highly delocalized π-π conjugated system, large specific surface area, and flexible surface-active groups. However, the drawbacks of low adsorption capacity and poor cycling performance have hindered the development of CMPs in the field of iodine adsorption. Herein, we propose a novel polyethyleneimine (PEI) chemically modified CMPs for efficient iodine adsorption. Firstly, the Sonogashira coupling method was used to prepare a conjugated microporous polymer with high-density carboxyl groups (CMP-COOH), followed by PEI chemical grafting modification to obtain a nitrogen rich conjugated microporous polymer (CMP-PEI). By utilizing the abundant amino adsorption sites in PEI, the affinity for iodine molecules is further enhanced. The results showed that when the PEI dispersion concentration was 15%, the iodine adsorption capacity of CMP-PEI prepared could reach up to 3.26 g/g, and the iodine release rate was as high as 95.6% at a temperature of 398 K, further indicating that the prepared CMP-PEI has good application value in the field of iodine adsorption.关键词：Conjugated microporous polymer;Iodine adsorption;Sonogashira coupling reaction;Polyethyleneimine modification205|78|0更新时间：2025-04-01
- 摘要：In order to make polypropylene melt-blown nonwoven (PP MB) have good dye adsorption and oil-water separation properties, M-PP MB first was prepared by hydrophilic modification of PP MB surface with polydopamine (PDA). Then Co-Al-based Layered Double Hydroxide (CoAl-LDH) were fixed on the surface of M-PP MB by one-step in situ hydrothermal synthesis to obtain CoAl-LDH@M-PP MB composite melt-blown nonwovens. The effects of the synthesis process conditions on the morphology and structure of CoAl-LDH@M-PP MB were explored, and the organic dye adsorption performance and oil-water separation performance were investigated. The results showed that when the raw material concentration ratio of Co to Al is 1:9, CoAl-LDH on the surface of the prepared CoAl-LDH@M-PP MB-1/9 presents disc shape with a sharp spine edge. Under the initial concentration of Congo red (CR) aqueous solution of 50 mg/L at 25 oC, the adsorption efficiency of CoAL-LDH@M-PPMB-1/9 for CR can reach over 99.00% within 30 min. When n-hexane is used as the oil phase, the separation efficiency of CoAl-LDH@M-PP MB-1/9 for n-hexane/water mixture can reach 99.33%, during 80 times of reuse, the oil-water separation efficiency of CoAl-LDH@M-PPMB-1/9 for n-hexane/water mixture is still greater than 97.41%, which shows that it has excellent oil-water separation and reuse performance.关键词：Polypropylene;Melt-blown nonwovens;CoAl-LDH;Dye solution adsorption;Oil-water separation56|27|0更新时间：2025-04-01
- 摘要：In the industrial field, the preparation of aromatic liquid crystal polyester (LCP) usually contains the acylation of monomers with phenolic hydroxyl group followed by melt polymerization. The composition of the acylated system has a crucial influence on the subsequent reactions and the properties of the final products. Based on this, this paper systematically investigated the effects of catalyst type and dosage, acylation agent dosage, and acylation duration on the acetylation of two different types of phenolic hydroxyl-containing monomers: the asymmetric functional group monomer, p-hydroxybenzoic acid (PHBA), and the symmetric bifunctional group monomer, biphenol (BP). It was found that the degree of acetylation of both monomers increased first and then reached an equilibrium with the increase of acylation time. For PHBA, under the acylation conditions, self-polymerization occurred among the acylated monomers and the degree of self-polymerization reached a certain equilibrium. The equilibrium degree varied with different catalyst types and acylation agent dosages, while is little affected by the dosage of the catalyst. When zinc acetate was used as the catalyst, PHBA had both high degrees of acetylation and self-polymerization. However, when N-methylimidazole (NMI) was used as the catalyst, the degree of self-polymerization of PHBA was significantly reduced. For BP, a small amount of single-acylation BP substances existed during the acylation process and gradually disappeared with the increase of the reaction degree. The catalytic efficiency of NMI for the acetylation of BP was higher than that of metal salt catalysts.关键词：Liquid crystalline polyesters;Acetylation;Self-polymerization;p-Hydroxybenzoic acid;4;4'-Dihydroxybiphenyl289|99|0更新时间：2025-04-01
- 摘要：In general, the chain sequence length of polyethylene has a certain distribution and its molecular chain has a high mobility, which can continue to crystallize during cooling and forming ordered crystal structures with different thicknesses. The non-isothermal crystallization behavior of polyethylene after isothermal crystallization at different temperatures for a certain period of time starting from different melt temperatures was investigated by using differential scanning calorimetry (DSC) technique in the present work. Compared to the melt temperature, the isothermal crystallization temperature and crystallization time have a stronger influence on the subsequent non-isothermal crystallization behavior. At the selected isothermal crystallization temperature, the number of crystallizable chain segments gradually increases with the extension of the isothermal time. As a consequence, the chain segments that can crystallize in the subsequent cooling process are mostly short chains, so the crystallization temperature corresponding to non-isothermal crystallization will gradually decrease with the extension of the pre-isothermal crystallization time. Within the selected isothermal crystallization time, especially the shorter the crystallization time, the higher the crystallization temperature, most of the chain segments in the system hardly crystallize, resulting in a significant effect on the subsequent non-isothermal crystallization process. Under such a condition, a higher crystallization temperature was always observed during non-isothermal crystallization process.关键词：Polyethylene;Melting temperature;Melting time;Crystallization temperature;Non-isothermal crystallization187|88|0更新时间：2025-04-01
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Molecular Design and Performance of a Low-Temperature Resistant and Waterborne Polyurethane Adhesive
摘要：With the rapid development of high-tech fields such as space technology and polar expeditions, the study of green adhesives that maintain good bonding performance in low-temperature environments has become an important research direction. Waterborne polyurethane (WPU) adhesives, which utilize water as a dispersant, show great potential as eco-friendly adhesive materials. However, the research on the low-temperature performance of WPU adhesives remains limited. In this study, a type of WPU adhesives with good performance at low temperatures were obtained using polypropylene glycol (PPG) and isophorone diisocyanate (IPDI) as the main raw materials, dimethylolpropionic acid (DMPA) as a hydrophilic chain extender, and ethylenediamine (EDA) as a small molecular chain extender. A series of WPU adhesives with different formulations were prepared by adjusting the mass fraction of DMPA and the initial molar ratio of isocyanate groups to hydroxyl groups. The study focused on investigating their glass transition temperature (Tg) and T-peel strength to obtain a WPU adhesive that has excellent low-temperature performance. The Tg of the adhesive was down to -35 ℃, and the T-peel strength measured by using aramid woven fabric as the substrate was 2.69 N/mm. The adhesive strips also exhibited outstanding mechanical properties, for example, a tensile strength of up to 5.51 MPa, an elastic modulus of 296.64 MPa, and an elongation of 504% at break. These results achieved in this research significantly contribute to the development of novel low-temperature-resistant green adhesive materials and their applications in the related fields.关键词：Waterborne Polyurethane;Adhesive;Low-temperature resistance;Mechanical property6|2|0更新时间：2025-04-01 - 摘要：Carbon fiber (CF) was modified using a PEI sizing agent and a PAMAM coupling agent to enhance the interfacial bonding strength in carbon fiber/polyetheretherketone (CF/PEEK) composites. Pure polyetheretherketone (PEEK) and CF/PEEK composites were fabricated via hot-press sintering. The study investigated the interfacial characteristics, mechanical performance, and tribological behavior of the composites both pre- and post-modification. Results indicated that the surface energy of the CF filler increased by 30.9% after PEI sizing modification and by 10.58% following treatment with the PAMAM coupling agent, relative to unmodified CF. In friction and wear tests conducted at a constant speed of 200 r/min, the friction coefficient and wear rate for PAMAM-CF/PEEK and PEI-CF/PEEK decreased by 11.63% and 72.34%, and 11.51% and 75.58%, respectively, compared to unmodified CF/PEEK. Under a fixed load of 90 N, similar reductions were observed: 15.1% and 52.53%, and18.78% and 63.04%, respectively. These results demonstrate improved interfacial bonding strength and tribological performance in the modified composites. Overall, CF/PEEK composites modified with PEI sizing exhibited superior interfacial bonding strength and tribological properties compared to those treated with the PAMAM coupling agent.关键词：Polyetheretherketone;Composites;Carbon fiber;Interface modifications239|87|0更新时间：2025-04-01
- 摘要：Solid-solid phase change materials (TAPCMs) with intrinsic flexibility and dynamic network structure were synthesized by using poly(ethylene glycol) (PEG) as soft segment, isophorone diisocyanate as hard segment and tannic acid as crosslinking agent. PEG played as a phase change component to reversibly storage and release heat. Carbamate and network structure offered by TA worked as supporting materials to endow TAPCMs stable solid-solid phase transformation and excellent mechanical properties. Besides, the phenolic hydroxyl groups in TA also provided a potential dynamic covalent bond, giving the function of self-healing and recyclability. TAPCMs possessed the highest latent heat of 84.70 J/g. The maximum tensile strength and elongation at break of TAPCM-4 were 22.73 MPa and 137.86%, respectively. After reprocessing, the mechanical properties can still reach 92% of the original one. This elaborate strategy is instructive for designing solid-solid phase change materials with intrinsic flexibility, self-healing, recyclability and environmentally friendly characteristics.关键词：solid-solid phase change materials;intrinsic flexibility;Self-healing;recyclability186|58|0更新时间：2025-04-01
Research Article
- 摘要：Glass transition is one of the most important properties of condensed matter. Chain connectivity endows polymers with complex glass transition behaviour that varies with the chain length. We have summarized more than half a century of research on the chain length dependence of glass transition of polymers. In the first part, we discussed the general phenomenon of the increase in glass transition temperature (Tg) and dynamical fragility (m) with increasing chain length until they reach saturation values. In the second part, the mechanisms proposed in the past decades to explain the general behaviour of the polymer glass transition were reviewed, including (1) the chain end effect, i.e., the chain ends associated with extra mobility and excess conformational freedom play a role in accelerating segmental movement and lowering polymer Tg; (2) the chain stiffness effect, i.e., the polymer chains stiffened as the molecular weight increased, leading to an increase in Tg with chain length before reaching the thresholds; (3) intramolecular coupling effect, i.e., dynamic couplings of secondary relaxations along the chains facilitate the segmental relaxation, leading to an increase of Tg with the chain length. We hope this review helps the readers gain a deeper understanding of the glass transition of polymers and the associated molecular mechanisms.关键词：Glass transition;Chain-length dependence;Chain-end effect;Chain stiffness;Intrachain coupling331|304|0更新时间：2025-04-01
- 摘要：With the improvement of environmental awareness, people pay more and more attention to the atomic economy and step economy of the material preparation process. Synthetic polymeric materials such as polyamide, polyester, and polyurea with excellent mechanical properties, chemical resistance, and thermal stability, can meet the needs of materials in different fields. Dehydrogenative coupling reactions can convert primary alcohols into aldehyde intermediates, which react in situ with amines and alcohols to form amides, esters, and ureas. This kind of reaction avoids the cumbersome substrate synthesis and the utilization of carboxylic acids and their derivatives. It has the advantages of mild reaction conditions, high selectivity and atomic economy, and has made significant progress in organic synthesis. However, relatively few studies exist on applying this distinctive coupling reaction for polymer preparation. In this review, we focus on recent advances in using dehydrogenative polymerization to prepare polyamides, polyesters, and polyureas. Initially, we introduced the unique properties of these three types of polymers and their widespread applications in industrial production and daily life, while also pointing out the limitations of traditional synthetic methods. Through comparison, we highlighted the significant advantages of dehydrogenative polymerization in the preparation of polar polymer materials. Subsequently, we summarized various transition-metal catalysts used in dehydrogenative polymerization and their catalytic mechanisms. Finally, we discussed the prospective development directions of dehydrogenative polymerization technology in the field of preparing polar polymer materials.关键词：Dehydrogenative polymerization;Polyamide;Polyester;Polyurea;Metal complexes483|513|0更新时间：2025-04-01
Review
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