最新刊期

    55 11 2024

      Review

    • Jing-yue Yan, Yu-min Liu, Hua-dong Huang, Can Gao, Huan-li Dong, Zhong-ming Li
      Vol. 55, Issue 11, Pages: 1441-1462(2024) DOI: 10.11777/j.issn1000-3304.2024.24152
      摘要:The field of organic electronics has made significant progress after more than 40 years of research, giving rise to a series of emerging related areas. Due to limitations such as limited conjugated size of small molecules and high degree of disorders in conjugated polymers, research in this field is currently facing performance limits and its development is distinctly hindered. The preparation of high-quality semiconductor crystals of conjugated polymers is of great significance for the study of their basic physical properties and the construction of organic optoelectronic devices with the high performance. However, due to the inherent characteristics such as high molecular weight, dispersibility, and easy entanglement between chains, the acquisition of highly ordered aggregates for conjugated polymers faces enormous challenges. Study on the crystallization of conjugated polymers is definitely important for preparing their high-quality crystals in order to overcome the current performance limitations in organic electronics, and would be expected to provide an important research platform for basic physical properties of conjugated polymers. Epitaxial crystallization is a surface-induced crystallization method. The existence of oriented substrate can reduce the nucleation barrier of crystallization processes and make the crystallization processes more easily to occur in comparison to the traditional solution crystallization. Therefore, epitaxial crystallization has become a common method for regulating the aggregation structure and properties of organic polymer semiconductor materials. In this contribution, we first briefly introduced the regulation of the aggregate structures of organic polymer semiconductor materials through traditional solution assembly and new oriented crystallization strategies. The factors of epitaxial crystallization and their advantages on regulating the aggregate structures and properties of organic polymer semiconductor materials were then particularly summarized. Future study on epitaxial crystallization in organic conjugated polymers was prospected in the end.  
      关键词:polymer semiconductors;Structure-property relationship;Structural control;Epitaxial crystallization   
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      Research Article

    • Design and Preparation of Antifreeze Silk-based Bioadhesive

      Xin-yang Li, Ni Chen, Gong-wen Yang, Zheng-zhong Shao
      Vol. 55, Issue 11, Pages: 1463-1475(2024) DOI: 10.11777/j.issn1000-3304.2024.24104
      摘要:Amidst growing demands for environmental protection and sustainable development, there is an urgent need within the industry for alternatives to traditional chemical adhesives, which are implicated in environmental contamination and health hazards. This study introduces an antifreeze silk fibroin bioadhesive designed to address the performance deficits of conventional bio-based adhesives in frozen conditions. The synthesis of this novel silk-derived adhesive employs a dual-stage process: initially crafting a silk fibroin-based adhesive matrix, followed by its integration with an aqueous solvent system to formulate the bioadhesive. This approach enables the long-term storage of protein powders under ambient conditions, with the flexibility of formulation and application upon demand. Additionally, the adhesive strength is readily adjustable through the modulation of substrate concentration. The adhesive efficacy is principally reliant on the hydrogen bonding capability, with the quantity of hydrogen bond sites provided by silk fibroin critically influencing the protein adhesive's binding properties. Incorporation of tannic acid, known for its strong affinity with silk fibroin, prevents the transition of silk fibroin chains from a random coil to a β‍-sheet, thereby preserving the bioadhesive's strength. The study further refines the silk fibroin to tannic acid ratio and solvent composition, opting for a binary solvent system of ethylene glycol and water. This choice markedly enhances the solubility of the silk fibroin bioadhesive and significantly depresses its freezing point, augmenting its antifreeze capabilities and facilitating substrate bonding at low temperatures. The adhesive also exhibits exceptional low-temperature stability and adaptability to fluctuations in ambient temperature. Experimental validations demonstrate that this bioadhesive surpasses the adhesive performance of conventional commercial chemical adhesives and other bio-based adhesives over a broad temperature range from -24 °C to room temperature. Consequently, the antifreeze silk fibroin bioadhesive developed in this study, with its eco-friendliness, biodegradability, and exceptional adhesive performance under extreme low-temperature conditions, shows great potential for applications in key areas such as packaging, biomedical, and environmental protection.  
      关键词:Silk fibroin;Tannic acid;Antifreeze;Bioadhesive;Eco-friendly   
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    • Catalytic Depolymerization of Crystalline Aliphatic Polycarbonates

      Xu-ming Lin, Ming-qian Wang, Xiao-yan Fu, Zhi-qiang Ding, Bin Wang
      Vol. 55, Issue 11, Pages: 1476-1486(2024) DOI: 10.11777/j.issn1000-3304.2024.24087
      摘要:The catalytic depolymerization and recycling of aliphatic polycarbonates have attracted increasing attention in recent years. The crystalline structure of aliphatic polycarbonates impedes the penetration of solvents and catalysts, thereby reducing depolymerization activity. Additionally, the thermal depolymerization reaction process is complex, accompanied by numerous side reactions and a lack of high selectivity in recovering the target product. Consequently, the depolymerization behaviors and products of aliphatic polycarbonate are highly complex and influenced by numerous factors. In this study, we investigated the depolymerization reactions and behaviors of poly(butylene carbonate), poly(pentylene carbonate), and poly(hexylene carbonate) under various catalysts and reaction conditions using intrinsic melting methods. Furthermore, the differences in product selectivities were characterized through-NMR spectroscopy. The results demonstrated that potassium tert-butoxide and sodium tert-butoxide were found to be highly effective catalysts for the depolymerization of poly(butylene carbonate), with distinct product selectivities. Specifically, potassium tert-butoxide was observed to favor the depolymerization process, resulting in the production of primarily fourteen-membered cyclic dimer (7CC)2. In contrast, sodium tert-butoxide exhibited a preference for the generation of seven-membered cyclic carbonate monomers (7CC). Theoretical calculations indicated that the production of (7CC)2 was a more dominant reaction pathway than the generation of 7CC. Increasing the reaction temperature was found to improve the selectivity for 7CC production. Poly(pentylene glycol carbonate) and poly(hexylene glycol carbonate) were observed to produce only the corresponding sixteen-/eighteen-membered cyclic dimers, with no eight-/nine-membered cyclic monomers being produced. The objective of this research is to provide an experimental and theoretical basis for further development of efficient depolymerization and recycling methods for aliphatic polycarbonates.  
      关键词:Aliphatic polycarbonate;Catalyst;Depolymerization and recycling;Cyclic carbonate   
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    • Dan Liang, Yang Jiang, Shi-hui Li, Dong-mei Cui
      Vol. 55, Issue 11, Pages: 1487-1494(2024) DOI: 10.11777/j.issn1000-3304.2024.24092
      摘要:The copolymerization of ethylene and 5-hexen-1-ol (M2) masked by 1.1 equivalents of AliBu3 is carried out by four rare-earth metal catalysts bearing different steric hindrances: (Flu-CH2-Ph)Sc(CH2- SiMe3)2(THF) (1), (Flu-CH2-C5H4N)Sc(CH2SiMe3)2 (2), (Flu-CH2CH2-NHC-C6H2Me3-2,4,6)Sc(CH2SiMe3)2 (3), (Flu-CH2CH2-NHC-C6H4Me)Sc(CH2SiMe3)2 (4). Among them, complex 1 shows the highest catalytic activity (1.32×106 g·molSc-1·h-1) but gives pure polyethylene without detectable M2 unit, and, in contrast, complex 2 is nearly inert. Under same conditions, the bulkier complex 3 shows moderate activity (0.38×106 g·molSc-1·h-1) and low comonomer incorporation (0.7 mol%). On switching to the bulkiest complex 4, the copolymerization process is obviously promoted with a catalytic activity of 1.24×106 g·molSc-1·h-1 and generates a copolymer with 1.8 mol% M2. For the polar vinyl monomers having different CH2 spacers between polar and vinyl groups, complex 4 exhibits the best catalytic performance for the copolymerization of ethylene with 10-undecene-1-ol with the highest catalytic activity (1.19×107 g·molSc-1·h-1) and the strongest incorporation ability (4.9 mol%). The influence of reaction conditions such as comonomer concentration, polymerization temperature and ethylene pressures on the catalytic performance of complex 4 are screened. The microstructures and thermal properties of the resultant copolymers are well-characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC) and differential scanning calorimeter (DSC).  
      关键词:Rare-earth metal;Polar monomer;Copolymerization;Functional polyolefin;Ethylene   
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    • Liang Zhu, Su-yun Jie, Er-yuan Fang, Bo-geng Li
      Vol. 55, Issue 11, Pages: 1495-1503(2024) DOI: 10.11777/j.issn1000-3304.2024.24117
      摘要:Liquid rubber is a class of viscous oligomers with low molecular weight, fluidity at room temperature and good processing properties. Telechelic liquid rubber with one functional group at each terminal end could undergo crosslinking, chain extension and other reactions with other monomers or polymers, further expanding the application fields of liquid rubber. Liquid styrene-butadiene rubber (LSBR) is a low molecular-weight copolymer of butadiene and styrene, which has good compatibility with many rubbers. One of commonly used functionalized butadiene styrene liquid rubber is hydroxyl-terminated butadiene styrene rubber (HTBS), which is usually produced via free radical polymerization or anionic polymerization. In this study, taking solution-polymerized styrene-butadiene rubber (SSBR) as a starting material, aldehyde-terminated styrene-butadiene rubber (ATBS) was obtained by the reaction-controlled phase-transfer catalytic epoxidation and oxidative cleavage of epoxy groups. Then, the oxime- and amino-terminated butadiene-styrene rubbers (OTBS and AmTBS) were further obtained by the conversion of terminal groups. The composition and structure of materials, intermediate products and AmTBS were characterized and analyzed by proton and carbon nuclear magnetic resonance (1H- and 13C-NMR), and Fourier transform infrared (FTIR) spectroscopies. The results showed that AmTBS was successfully synthesized. The amine value of AmTBS was determined according to the chemical titration and the amino functionality was calculated to be approximately 2.0. The thermal properties of products were analyzed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results of rheological properties of AmTBS indicated that they matched the characteristics of Newtonian fluids and their intrinsic viscosities were sensitive to the temperature in a certain range. The AmTBS prepared by the degradation method possessed superior properties and could further broaden the application fields of LSBR.  
      关键词:Styrene-butadiene liquid rubber;Degradation;Amino-terminated styrene-butadiene rubber   
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    • Ling-feng Huang, Dong-po Song, Yue-sheng Li
      Vol. 55, Issue 11, Pages: 1504-1517(2024) DOI: 10.11777/j.issn1000-3304.2024.24101
      摘要:High environmental tolerance is a critical requirement for coating applications, particularly in automotive paint. This study successfully fabricated ordered porous photonic microspheres with poly(methyl methacrylate) (PMMA) as the framework using an organized spontaneous emulsification (OSE) mechanism, showing vibrant and adjustable structural colors. PMMA with narrow molecular weight distributions was synthesized via atom transfer radical polymerization (ATRP), and the efficient removal of terminal double bonds resulting from disproportionation termination was achieved through thiol-ene click reactions. Additionally, PMMA macromonomers with norbornene units were prepared through esterification reactions. By employing sequential ring-opening metathesis polymerization (ROMP), (poly(norbornene-g-PMMA)-b-(poly(norbornene-g-PEO)) (PMMA-b-PEO) bottlebrush block copolymers (BBCPs) were successfully synthesized with tunable number-average molecular weights ranging from 174 kDa to 359 kDa and low PDIs below 1.2. Pore diameter is tunable in a large range from 178 nm to 287 nm, resulting in photonic bandgaps changing from 437 nm to 618 nm. Photonic pigments with various colors across the whole visible range are therefore obtained. In addition, bio-based and environmentally safe anisole was utilized as the oil phase instead of toluene during the OSE process, enhancing the safety and eco-friendliness of the material preparation process, eliminating potential harmful residues, and facilitating large-scale production and application. PMMA-based structural color pigments are anticipated to demonstrate outstanding weather resistance and offer significant potential for applications like automotive paint coatings.  
      关键词:Block copolymer;Self-assembly;Ecofriendly materials;Structural color   
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    • Chang-kai Zhou, Peng-da Fang, Hao Zhang, Zhe Sun, Feng Yan
      Vol. 55, Issue 11, Pages: 1518-1528(2024) DOI: 10.11777/j.issn1000-3304.2024.24095
      摘要:With the continuous improvement of life quality, the demand for higher food quality has risen. Traditionally printed information on food packaging, such as production date and shelf life, falls short of assessing food quality and freshness adequately. Visual intelligent packaging can determine the freshness of food by changing colors, but the potential for food contamination due to pH indicator leakages with long response time poses a threat to food safety and quality. Therefore, polymer dyes that exhibit good biocompatibility, rapid pH response, and resistance to migration are increasingly essential in visually intelligent packaging applications. The phenothiazine cationic dye Azure B, which is sensitive to pH fluctuations, was incorporated into a poly(acrylamide-acrylic acid) hydrogel by electrostatic interactions. The research scrutinized the internal cross-linking of the synthesized hydrogel film (PAMA-Az) using Fourier transform infrared spectroscopy and evaluated the mobility of Azure B within the hydrogel through a UV spectrum. Furthermore, a comprehensive assessment of the physical and chemical properties of PAMA-Az, including discoloration response, mechanical strength, swelling behavior, ammonia gas sensitivity, and color reversibility, was conducted. Results indicated that the pH-responsive PAMA-Az formed by electrostatic interactions possessed a more compact structure, improved color-changing responsiveness, and lower Azure B mobility compared to the blending hydrogel. The color transition of PAMA-Az from blue to lavender and finally pink within the pH range of 7-12, coupled with its swift response to ammonia vapor and color reversibility, highlights its potential for visual food intelligent packaging. In a shrimp freshness monitoring experiment, the PAMA-Az hydrogel film, used as a contact substrate, successfully achieved the visual assessment of shrimp freshness, where a color change from blue to pink signaled rotting. Consequently, the fast-response and low-mobility pH-responsive hydrogel film demonstrates promising applications in visual food intelligent packaging and gas-sensitive labeling.  
      关键词:pH-Responsive;Azure B;Electrostatic interaction;Hydrogel film;Intelligent packaging   
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    • Hao-yu Zhang, Wei Chen
      Vol. 55, Issue 11, Pages: 1529-1537(2024) DOI: 10.11777/j.issn1000-3304.2024.24114
      摘要:The in situ detection of the microconformation of polymers in a shear field from the molecular level not only plays an important role for demonstrating the molecular mechanism of polymer chains' dynamic behavior such as deformation and diffusion, but also serves as a crucial link in developing advanced polymer processing technology. However, due to the conformational change scale of polymer chains falling within the range from 0.1 nm to 10 nm, conventional characterization methods, such as dynamic light scattering and fluorescence microscopy techniques, are difficult to meet the requirements of spatial resolution needed for characterization. To address this problem, the fluorometer was modified by adding a Couette rheofluorescence cell on the detection optical path. Since the Couette fluorescence cell can apply different shear rates to the sample, the modified fluorometer is able to detect in situ fluorescence signals of samples in a shear field. In order to characterize the conformational changes of the polymer chain, fluorescent donor and acceptor groups were labeled to a single polymer chain through covalent bonds Based on the positive correlation between the fluorescence resonance energy transfer (FRET) efficiency and the distance between the fluorescent donor and acceptor groups, a FRET spectroscopy has been used to achieve in situ characterization of the solution shear conformation of polymer chains by analyzing the change of the FRET efficiency between fluorescent donor and acceptor groups labeled on the same polymer chain as a function of the shear rate. For the first time, it was observed in situ at the molecular level that polymer chains under shear showed the conformational change modes of "whole driven by local" in dilute solutions and "local driven by whole" in semi-dilute solutions, respectively. This study provides new methods and ideas for experimentally carrying out in situ studies on the conformational evolution of polymer chains, and has an advancing effect on the development of molecular rheology.  
      关键词:Fluorescence resonance energy transfer;Chain conformation;Conformational evolution;Shear field   
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    • Ge Chen, Xiao-li Wang, Xiao-fan Liang, Huan Zhang, Xiao-tong Chen, Lei Shen, Lei Hou, Yue Zhao, Wei-chao Shi
      Vol. 55, Issue 11, Pages: 1538-1548(2024) DOI: 10.11777/j.issn1000-3304.2024.24119
      摘要:Ethylene-vinyl acetate copolymer (EVA) adhesive is an environment-friendly polymer with excellent thermomechanical performance. It is widely used in furniture, cables, pipelines and so on. The storage and service environment of EVA adhesives, such as temperature and humidity, affect the crystal structures and their mechanical properties. To explore the relationship between crystallization and mechanical properties, we treat EVA adhesives with long-term annealing experiments under thermal or thermal/humid conditions, respectively. The results reveal that short time annealing leads to slight improvement in the mechanical properties, which is ascribed to the promoted crystallization determined by the differential scanning calorimetry. The small angle X-ray scattering experiment shows that annealing does not apply significant influence on the crystal thickness, while the wide angle X-ray scattering experiment indicates preferential crystal growth of the (110) plane rather than the (200) plane. Using polarized small angle laser scattering, we further find that spherulites in EVA adhesive is mainly made of thermally stable lamellar crystals which completely melt above 80 ℃. In comparison, small crystallites can be eliminated below 60 ℃ during long-term annealing. This work sheds insight into the relationship between crystallization and mechanical properties of EVA adhesive in thermal or humid environments, and provides a key experimental basis for optimizing the storage and service conditions.  
      关键词:Ethylene-vinyl acetate copolymer adhesive;Thermal annealing;Crystallization;Scattering   
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    • Cheng-Yu Li, Yi-hu Song
      Vol. 55, Issue 11, Pages: 1549-1560(2024) DOI: 10.11777/j.issn1000-3304.2024.24121
      摘要:Rubber nanocomposites show marked strain softening under large-amplitude oscillating shear and large strain cyclic tensile deformations. Due to the interface effect, phase area size and particle distribution, the strain softening behaviors of nanocomposites based on filler filled rubber blends matrices are more complicated and there are rare methods to regulate the rubber crosslinking, phase morphology and rheological behaviors. Herein the effects of ionic liquid (IL) 1-butyl-3-methyl imidazole acetate on the phase structure, filler dispersity, vulcanization kinetics and rheological behaviors of silica filled natural rubber (NR)/butadiene nitrile rubber (NBR) nanocomposites were studied. The effects of IL of 0.1 and 1 parts per hundred parts of rubber on the nanocomposites with different silica contents were investigated to regulate their microstructure and rheological behavior. The results show that IL can promote the vulcanization of rubber, reduce the swelling ratio of vulcanizates slightly, and reduce the sizes of the rubber phases. IL can weaken the Payne effect of highly filled nanocomposites and reduce the softening energy density without affecting the hysteretic energy density accompanying the Mullins effect. The results are enlightening for adjusting the rheological behavior and mechanical properties of nanocomposites by adjusting the interaction between nanoparticles and various rubber phases.  
      关键词:Rubber nanocomposites;Silica;Ionic liquid;Strain softening   
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    • Xin-yue Xu, Shi-long Dong, Qiao-long Yuan
      Vol. 55, Issue 11, Pages: 1561-1574(2024) DOI: 10.11777/j.issn1000-3304.2024.24115
      摘要:Five ethynyl-terminated poly(silylene acetylene) (ETSA) resins with different side groups at Si atom were synthesized using the Grignard reagent method. The structures of ETSA resins were characterized by proton nuclear magnetic resonance (1H-NMR) and Fourier transformation infrared (FTIR). The size exclusion chromatography was used to measure the molecular weight and distribution of ETSA resins. The curing behaviors of ETSA resins were investigated using differential scanning calorimetry (DSC). The thermal stability of cured ETSA resins were studied by thermogravimetric analysis (TGA). Furthermore, the microporous structure of cured ETSA resin was investigated using high resolution transmission electron microscopy (HRTEM) and small angle X-ray scattering (SAXS). Additionally, two nickel-based catalysts were used to catalyze the curing reaction of the ETSA resins, and the catalytic effect of the catalysts on the curing reaction of ETSA resins were evaluated by DSC, FTIR and TGA. The results show that the degree of polymerization of ETSA resin decreases with increase of the volume of side group at Si atom in the backbone of ETSA. The peak exothermic temperature of the ETSA moves to a high temperature during curing, and the exothermic enthalpy and curing degree of the ETSA decrease with the increase of the volume of side group. The cured ETSA resins display excellent thermal stability. The temperature of 5% weight loss (Td5) of the cured ETSA resins in nitrogen and air are higher than 450 ℃. The residual yield at 800 ℃ (Yr800) in nitrogen and air of the cured ETSA resins are larger than 80% and 27%, respectively. The microporous size in the cross-linked networks of ETSA increases with the increase of the volume of side group. The nickel-based catalysts exhibit the good catalytic effect on the curing reaction of ETSA. The inital temperature of catalyst-curing ETSA resins can drop over 50 ℃, but the Yr800 of the catalyst-cured ETSA resins change not much. The ETSA resin is promising to be used as a highly heat-resistant resin matrix and a polymeric precursor.  
      关键词:Poly(silylene acetylene);Hybrid resin;Side group;Cure reaction;Thermal stability   
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    • Jing Ma, Yue Gong, Guan-qi Zheng, Teng Fu, Xiu-li Wang
      Vol. 55, Issue 11, Pages: 1575-1585(2024) DOI: 10.11777/j.issn1000-3304.2024.24109
      摘要:Direct recycling of leather waste (LW) into high value-added products has always been a challenge for the leather industry. In this study, a "three sources in one" leather-based intumescent flame retardant (PA@LW@APP) was prepared in aqueous solution by electrostatic interaction, using LW rich in nitrogen/carbon elements as a carbon/gas source and ammonium polyphosphate (APP) as an acid source. Then PA@LW@APP was introduced into thermoplastic polyurethane elastomer (TPU) by melt blending. It was found that when the addition content of PA@LW@APP is 5 wt%, TPU5 can achieve UL-94 V-0 rating. The flame retardant TPU forms an intumescent char layer during cone test that blocked the external fire source and combustible gas, showing excellent heat suppression, smoke suppression and char-forming abilities. Compared with pure TPU, the peak heat release rate (pHRR), total heat release (THR) and total smoke production (TSP) of flame retardant TPU containing 15 wt% PA@LW@APP were reduced by 71.1%, 36.0% and 51.4%, respectively. In addition, the encapsulated structure of PA@LW@APP made it well dispersed in the TPU substrate and not easy to agglomerate, and the flame retardant TPU maintained good tensile toughness. This work not only realizes the high-value recycling of leather waste through a green and simple method, while also giving TPU excellent flame retardant properties.  
      关键词:Thermoplastic polyurethane;leather waste;intumescent flame retardant;Mechanical properties;high-value recycle   
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    • Yu-jie Wang, Hui-fang Nie, Xiao-kai Xue, Zhuang-long Xie, Fei Wang, Shi-min Wang, Ya-meng Wan, Bao-yuan Chen
      Vol. 55, Issue 11, Pages: 1586-1596(2024) DOI: 10.11777/j.issn1000-3304.2024.24098
      摘要:With the gradual increase of environmental protection requirements, the utilization of highly toxic organic solvents has become the main factor restricting the production and application of polyurethane-based (PU) transparent coatings, and enabling PU alcohol solubility by structural design is an effective strategy for preparing environmentally friendly transparent coatings. In this study, poly(propylene oxide diol) was used as the soft segments, and the alcohol solubility and transparency of PU coatings were imparted by introducing the alicyclic structure of isophorone diisocyanate into the hard segments. The chemical structure of the alcohol-soluble PU coatings was characterized by Fourier transform infrared spectroscopy, the alcohol-soluble and optical properties were characterized by ultraviolet-visible spectrophotometry, the hydrophobicity was observed by static contact angle test, the thermal stability was determined by thermo-gravimetric analyzer, and the effect of the content of the hard segments on the mechanical properties was analyzed by electronic universal testing machine. Furthermore, the applied properties were investigated by scratch tests and corrosion resistance measurements. The results show that the ring structure with large spatial site resistance makes the hydrogen bonding between urethane groups in the hard segments weak, and the hydrogen bonding between ethanol and urethane groups promotes the solubilization of the PU coatings, which in turn shows favorable alcohol solubility. The amorphous state of the soft and hard segments resulted in good transparency, but with the increase of the hard segments content, the microphase-separated degree of the PUs increased, which resulted in a decrease in the light transmittance of the coatings, a slight decrease in the hydrophobicity, and a significant increase in the tensile strength. The prepared alcohol-soluble PU-based transparent coatings have excellent hydrophobicity, thermal stability, anti-peeling and corrosion resistance, and are expected to be used in optical devices, high-end glass instruments and other applications.  
      关键词:Polyurethane;Cyclic hard segment;Alcohol soluble;Hydrophobic;Transparent coating   
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    • Xin We, Pei-xian Wang, Ming-liang Wang, Dong Huang, Zhong Wei, Xiao-ling Song, Gong-ying Wang, Zi-qing Wang
      Vol. 55, Issue 11, Pages: 1597-1607(2024) DOI: 10.11777/j.issn1000-3304.2024.24100
      摘要:To address the challenges associated with the inadequate barrier properties and reduced elastic modulus of poly(butylene adipate-co-terephthalate) (PBAT), a series of PBAT/poly(butylene carbonate) (PBC)/epoxidized soybean oil (ESO) composites were prepared by melt blending ESO as a compatibilizer and PBC as the second component with PBAT. The effects of ESO content and PBC content on the thermal properties, crystallization properties, mechanical properties, and barrier properties of the composite materials were investigated through Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and other relevant characterization tools. Additionally, the compatibility mechanism of ESO on the composite materials was discussed. The results demonstrated that the epoxy groups in ESO enhanced the compatibility of PBAT and PBC through a ring-opening reaction with the end groups of PBAT and PBC. Furthermore, the crystallization properties and thermal stability of the composites were improved. SEM images showed that the delamination in the composites disappeared after the addition of ESO, and a linear fiber structure appeared, further proving the compatibility enhancement. At the same time, the addition of ESO significantly improved the ductility of the composites. The elongation at break of PBAT/PBC composites increased from 353% to 805% when the ESO content in the composites increased from 0% to 7.0%; meanwhile, PBC and ESO show an excellent synergistic effect in improving the elongation at break of the composite materials. In addition, the addition of PBC can significantly improve the barrier properties and stiffness of PBAT/PBC composites. The oxygen and water vapor barrier properties of composites increased by 73% and 64.7%, respectively, as the PBC content increased from 0 wt% to 80 wt%. Furthermore, the modulus of elasticity increased by 254%. The comprehensive performance of PBAT was notably improved through the incorporation of PBC and ESO as modifying materials, thereby promising to broaden the application fields of PBAT.  
      关键词:Poly(butylene adipate-co-terephthalate);Poly(butylene carbonate);Compatibilization;Biodegradable plastics;Barrier performance   
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    • Chao Xu, Bin Zheng, Sen-miao Li, Peng Zheng
      Vol. 55, Issue 11, Pages: 1608-1616(2024) DOI: 10.11777/j.issn1000-3304.2024.24123
      摘要:Steered Molecular Dynamics (SMD) simulations represent an important computational approach for uncovering the mechanistic behaviors of bio-macromolecules under mechanical forces, closely resembling experimental techniques such as single-molecule force spectroscopy for protein unfolding. Despite its widespread application, the computational intensity of simulating large molecular systems has traditionally constrained the scope of such studies. Recent technological advancements in computer hardware have now enabled more extensive and economically viable simulations. This study investigates the unfolding of Interleukin-6 (IL-6) to determine the optimal hardware configurations for SMD simulations using GROMACS. Our findings highlight that a configuration of eight CPU cores to one GPU yields the most efficient performance. Moreover, CPUs with higher clock speeds and GPUs with greater full precise float 32 calculation ability directly enhance simulation outcomes. We also examined the impact of atom count on simulation efficiency. Additionally, we identified the most suitable hardware for SMD simulation by analyzing the cost-effectiveness of the hardware involved in this article. Our research not only elucidates the optimal hardware setup for SMD simulations of protein unfolding but also extends the feasibility of such detailed molecular investigations to a broader research community, offering a pathway to more accessible and insightful mechanistic studies at the molecular level. This also provided an important foundation for understanding and studying the mechanical mechanisms of more complex polymer unfolding in the future.  
      关键词:Molecular dynamics simulation;Protein unfolding;Efficiency optimization   
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      更新时间:2024-12-24
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