Polymers
·
2020
·Vol. 12
·期 9
·2048
·
IF 3.426
Yiwu Liu,Ao Tang,Jinghua Tan,Xianqing Zhao,Chengliang Chen,Ding Wu,Yuhui Li,Pan He,Hailiang Zhang
A high-barrier polyimide (2,7-CPI) was synthesized through the polymerization of pyromellitic dianhydride (PMDA) and a novel diamine (2,7-CDA) containing carbazole moiety. The synthesized diamine and polyimide were fully characterized by elemental analyses, FTIR and NMR. The 2,7-CPI displays very attractive barrier performances, with oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) low to 0.14 cm3·m−2·day−1and 0.05 g·m−2·day−1, respectively. Meanwhile, 2,7-CPI also exhibits exceptional thermal stability with a glass transition temperature (Tg) of 467 °C, 5% weight-loss temperature (Td5%) of 550 °C under N2and coefficient of thermal expansion (CTE) of 3.4 ppm/K. The barrier performances of 2,7-CPI are compared with those of a structural analogue (2,7-CPPI) and a typical polyimide (Kapton). Their barrier performances with respect to microstructure were investigated by molecular simulations, wide angle X-ray diffraction (WAXD), and positron annihilation lifetime spectroscopy (PALS). The results show that 2,7-CPI possesses better coplanar structure and more number of intermolecular hydrogen bonds among the three PIs, which result in tight chain packing and thereby high crystallinity, low free volume, and decreased chains mobility. That is, the high crystallinity and low free volume of 2,7-CPI reduce the diffusion and solubility of gases. Meanwhile, the poor chains mobility further decreases the gases diffusion. The reduced diffusion and solubility of gases consequently promote the improvement of barrier properties for 2,7-CPI. The polyimide has a wide application prospect in the field of flexible electronic packaging industries.Keywords:polyimide;carbazole;barrier properties;molecular simulations
研究领域:
材料科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
LWT-FOOD SCIENCE AND TECHNOLOGY
·
2023
·
IF 6
Yujie Chen,Ruhui Liu,Jingyan Li,Yanjie Wang,Chunfeng Guo,Xin Lü
1-Oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) is the most abundant triacylglycerol (TAG) molecule in Chinese human milk. The selectivity of three lipases including Rhizomucor miehei lipase (RML), Thermomyces lanuginose lipase (TL), and Candida antarctica lipase (CALB) in OPL synthesis were evaluated. The effects of different reaction conditions on selectivity were first investigated. Unexpectedly, the three sn -1,3 regioselectivity lipases, also have selectivity for the structure of product TAGs. Compared with symmetric TAGs, lipases had poor selectivity toward asymmetric OPL. Furthermore, molecular simulations were used to deeply understand the molecular factors affecting lipase selectivity. The results showed that hydrophobic interactions, lipases lid domain flexibility, and the stability of hydrogen bonds between lipases and TAGs were the main molecular factors responsible for the selectivity of lipases.
研究领域:
生物化学
·
食品科学
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·
IF 3.5
Yu Fengqin,Xie Qiang,Zhang Zhijun,Yang Shuai,Liu Jinchang,Ren Qiang,Liang Dingcheng
Zeolites are widely used for removing volatile organic compounds (VOCs) in industrial processes. However, the understanding of the competitive adsorption behavior of multicomponent VOCs on zeolites remains insufficient. This study employed grand canonical Monte Carlo simulation to investigate the adsorption behaviors of nonpolar benzene and polar ethyl acetate in both pure and mixed forms on FAU, LTA and MFI zeolites. The effects of zeolite topology, Si/Al ratio, and compensating cations on competitive adsorption were explored. The results revealed that the adsorption capacities of benzene and ethyl acetate on FAU and LTA zeolites gradually increased with increasing Si/Al ratio, consistent with the increasing trends in their specific surface areas and pore volumes. However, the MFI zeolite shows no significant change in these properties with varying Si/Al ratios. Zeolites modified with Ca 2+ significantly improved the benzene and ethyl acetate adsorption capacities, while impact on ethyl acetate adsorption is minimal. Zeolites modified with K + reduced the adsorption capacities for both benzene and ethyl acetate. For binary mixtures, Na-FAU-1, Na-LTA-1, and Na-MFI-15 exhibited high selectivity for ethyl acetate. Increasing the Si/Al ratio and K + -modification reduced the adsorption selectivity of these zeolites for ethyl acetate. Ca 2+ -modification reduces the selectivity of LTA-1 toward ethyl acetate, with minimal impact on FAU-1 and MFI-15. Dynamic adsorption experiments with commercial zeolites confirm the reliability of the simulation results in predicting benzene and ethyl acetate adsorption performance. This study is expected to provide guidance for selecting appropriate zeolites for VOCs mixtures in practical applications. Graphical abstract
研究领域:
环境科学
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化学工程
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DOI
高影响因子
CORROSION SCIENCE
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2023
·
IF 8.3
Feng-Ting Li,Zhi-Kun Wang,Yi Zhou,Li-Zhi Li,Yue-Qi Liu,Li Wang,Chun-Ling Li,Hua-Feng Zhu,Shuang-Qing Sun,Song-Qing Hu
Chemical modification is effective in improving the corrosion inhibition efficiency of carbon dots (CDs) on steel. Here, the imidazolium ionic liquids (IL) modified-CDs (IL-CDs) are synthesized and proved to be mixed-type corrosion inhibitors . The IL increases the pyrrole N content and facilitates the formation of a denser inhibitor film. Molecular simulations confirm that the IL reduces the π-π interaction between CDs, endowing IL-CDs with higher water solubility and better corrosion inhibition effect than CDs. The lower orbital energy gap and larger positive electrostatic potential distribution enable the inhibition efficiency of IL-CDs of 97.11% in 1 M HCl, much superior to CDs (90.80%).
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 41
·e52994
·
IF 3.057
Jing Ni,Hongchao Niu,Shiqing Lai,Chanjuan Liu,Li Zhou,Lichun Wang,Xiaohua Huang
Through one-step copolymerization of 4-(4-[1-morpholinyl]phenyl)-2,6-bis(4-aminophenyl)pyridine (MPAP), 9,9-bis(4-aminophenyl)fluorene (BAFL), and (4,4′-hexafluoroisopropylidene)diphthalic anhydride (6FDA), a series of polyimides containing morpholine group, pyridine ring, fluorene “cardo” pendant and hexafluoroisopropyl group are obtained. The synthesized polyimides have good thermal stability, high transparency, outstanding hydrophobicity and excellent solubility in not only high-boiling solvents but also low boiling-point solvents. Furthermore, polyimide films have large molecular chain spacing, which is consistent with the free volume calculated by molecular simulation. Consequently, polyimide membranes display better gas permeability values of CO 2 (up to 24.47 Barrer) and He (up to 45.04 Barrer), and good ideal gas selectivity values of CO 2 /N 2 (up to 15.33 Barrer) and He/N 2 (up to 23.89 Barrer), which also shows potential application of polyimide matrix materials in gas separation.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 23
·4250
·
IF 4.329
Hongchuan Dong,Yunfan Liu,Yanming Cao,Juzhen Wu,Sida Zhang,Xinlong Zhang,Li Cheng
Moisture is detrimental to the performance of epoxy resin material for electrical equipment in long-term operation and insulation. Therefore, moisture absorption is one of the critical indicators for insulation of the material. However, some relevant test methods, e.g., the direct weighing method, are time-consuming, and it usually takes months to complete a test. For this, it is necessary to have some modification to save the test time. Firstly, the study analyzes the present prediction method (according to ISO 62:2008). Under the same accuracy, the time required is reduced from 104 days to 71 days. Subsequently, the Langmuir curve-fitting method for water absorption of epoxy resin is analyzed, and the initial values of diffusion coefficient, bonding coefficient, and de-bonding coefficient are determined based on the results of molecular simulation, relevant experiment, and literature review. With the optimized prediction model, it takes only 1.5 days (reduced by 98% as compared with the standard prediction method) to determine the moisture absorbability. Then, the factors influencing the prediction accuracy are discussed. The results have shown that the fluctuation of balance at the initial stage will affect the test precision significantly. Accordingly, this study proposes a quantitative characterization method for initial trace moisture based on the terahertz method, by which the trace moisture in epoxy resin is represented precisely through the established terahertz time-domain spectroscopy system. When this method is used to predict the moisture absorbability, the experimental time may be further shortened by 33% to 1 day. For the whole water absorption cycle curve, the error is less than 5%.Keywords:epoxy resins;Langmuir;terahertz;molecular simulation;prediction
研究领域:
材料科学
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电气工程
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Yao Tong,Shangru Zhai,Kai Wang,Hongsheng Li,Qingda An
The solubility of saccharin in seven pure solvents, including methanol, ethanol, n -propanol, isopropanol, isobutanol, ethyl acetate and acetone, was determined from 278.15 K to 323.15 K by using a gravimetric method at atmospheric pressure. The solubility of saccharin is positively related to temperature in all selected solvents. The cooperation effect between polarity and interaction bonding was revealed by the molecular simulation study to give the explanation for the sequence of solubility in various solvents. Besides, the experimental solubility data was correlated by the modified Apelblat equation, λh equation, Wilson model and NRTL model. The results indicate that all the models could give satisfactory correlation results, whereas the modified Apelblat model shows the best fitting result. Furthermore, the thermodynamic properties of the dissolution process of saccharin in the appointed solvents, including the Gibbs energy, enthalpy and entropy of dissolution, were also calculated and discussed according to the Wilson model and the result turns out that the dissolution process of saccharin is endothermic.
研究领域:
物理化学
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药物化学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Hui Yan,Yanbo Liu,Haoyu Peng,Jiahui Li,Mingyang Chen,Junbo Gong
The solubility of o -methoxybenzoic acid (OMBA) in twelve pure solvents range from 283.15 to 323.15 K was investigated by the experiments and molecular simulations. The result of gravimetric method showed that OMBA has the highest solubility in acetone and the lowest solubility in water. Molecular simulations of MPI, MEPs, HS and SFE were employed to understand the dissolution behavior. In particular, MPI had proved to be an uncommon but effective parameter, which can provide a better explanation based on the polarity of “like dissolves like”. Moreover, the intermolecular interactions derived from HS analysis indicated that the H-H contacts as well as the C=O∙∙∙H-O hydrogen bonding interactions were dominant in the crystal packing of OMBA. Six thermodynamic models were further selected to correlate experimental solubility results successfully as the A R D % values of the six models were less than 7%. The mixing thermodynamic properties obtained from the correlated results of the NRTL model, indicating that the dissolution process is spontaneous and entropy-driven. The experimental data can be used as a useful basis for the industrial production of intermediate product OMBA.
研究领域:
化学工程
·
物理化学
·
分子模拟
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Wenjin Niu,Wen Nie,Qiu Bao,Qifan Tian,Ruoxi Li,Xiaohan Zhang,Chenfeng Shi,Ke Tong,Zhihui Zhang
The wettability of coal dust by surfactant-regulated solutions is influenced by the hydrophilic structures of the surfactants. This study combines macro- and microscopic experiments to determine the wettability performance of four surfactants with identical hydrophobic groups but different hydrophilic groups. Through molecular simulation, a molecular-level evaluation standard for the surfactant’s impact on coal dust wettability was established. Additionally, the correlation mechanism between the electrostatic potential distribution of the hydrophilic groups and their wettability was identified. Sulfonic groups—compared with sulfate, hydroxyl, and amino groups—can more effectively enhance the solution’s wettability, reducing the solution’s surface tension to as low as 22.1 mN/m and achieving a molecular wettability area of 78.84. Furthermore, the electrostatic potential extreme of the sulfonic group was − 53.61 kcal/mol, with an electrostatic potential wettability area of 28.99 Å2. This represents an improvement of approximately 34.43 % and 5170.91 %, respectively, compared with hydroxyl groups. Greater electrostatic potential extremes and electrostatic potential wettability areas led to stronger electrostatic adsorption, more adsorbed water molecules, and better wettability of coal dust. This study provides theoretical guidance for the rational design of functional surfactants for surface engineering and pollution control applications.
研究领域:
环境科学
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化学工程
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材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2023
·
IF 3.8
Meng Song,Chaokang Chang,Meng Wang,Lei Wang,Fang He,Sizhu Wu
Materials Studio 2018 software was used to model β -cyclodextrin ( β -CD) and 16 flavonoids, and Auto Dock 4.0 was used for molecular docking. From the molecular dynamics simulations, curcumin (CUR) was identified as the most suitable inclusion in β -CD. For comparison, the inclusion of CUR in 2, 6-dimethyl- β -cyclodextrin (DM- β -CD) and 2-hydroxypropyl- β -cyclodextrin (HP- β -CD) was simulated. The calculated parameters included solubility parameters, binding energy, mean square displacement, radial distribution, and hydrogen bonding. The simulation results showed that DM- β -CD was most effective for the inclusion of CUR. Inclusion complexes of CUR with β -CD, DM- β -CD, and HP- β -CD were prepared by freeze-drying. The inclusion complexes were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and UV-visible (UV-vis) spectra. The experimental results also showed that DM- β -CD was most effective for the inclusion of CUR, which is in agreement with the simulation results.
研究领域:
药剂学
·
计算生物学
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产品关联
DOI
高影响因子
Processes
·
2023
·Vol. 11
·期 7
·2199
·
IF 3.5
Liang Shen,Yifang Liu,Jiabao Gong,Erle Qiao
Soil is the main aggregation site of polycyclic aromatic hydrocarbons and an important pathway of migration to other media. In this paper, the adsorption behavior of pyrene and seven different types of surfactants on kaolinite surfaces was studied by molecular dynamics simulation and desorption testing. The molecular dynamics simulation results showed that pyrene was more easily adsorbed on the 001 (-) side of kaolinite. SDBS, SDS, TW80, and TX-100 had strong interactions with pyrene, encapsulating pyrene molecules in aggregates. However, when the concentration of surfactant was too high, the desorption of pyrene molecules on a kaolinite surface will be inhibited. The desorption of pyrene molecules will be inhibited in the presence of BS-12, TW80, and TX-100, while the desorption process can be promoted by using CTAC, DDBAC, SDBS, and SDS as soil remediation agents. The removal rate of pyrene gradually increased with the increase of SDS dosage, while for SDBS, the removal rate showed a trend of first increasing and then decreasing. When the concentration of SDS was 0.014 mol/L, the elution rate of pyrene reached 72.86%. The molecular dynamics simulation results were similar to the desorption test results, verifying the reliability of molecular dynamics simulation. The research results provide theoretical support for the selection of surfactants in the remediation process of pyrene-contaminated soil.Keywords:soil remediation;polycyclic aromatic hydrocarbons;surfactants;molecular simulation
研究领域:
环境科学
·
土壤学
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2023
·
IF 8.8
Ying Bu,Chaonan Sun,Jiaqi Guo,Wenhui Zhu,Jianrong Li,Xuepeng Li,Yi Zhang
The purpose of this study was to screen and verify salt-enhancing peptides that can effectively reduce sodium consumption from Largemouth bass myosin through virtual hydrolysis, molecular simulation, and sensory evaluation. The human transmembrane channel-like 4 (TMC4) was constructed using Alphafold2, with 93.3 % of amino acids falling within allowed regions. A total of 19 peptides were predicted through virtual hydrolysis and screening. DAF, QIF, RPAL, and IPVM significantly enhanced the saltiness perception, and QIF exhibited the most pronounced effect in enhancing saltiness ( P < 0.05). The residues Ala258, Ser546, Ser603, Phe259, Cys265, Glu539, Lys278 and Ser585 were identified as key binding sites. The TMC4-DAF complex achieved stability after 20, 000 ps, exhibiting an average RMSD value of 0.84 nm. DAF consistently displayed fluctuations at approximately 3.05 nm, and the number of hydrogen bonds varied between 3 and 5. These results suggested that Alphafold2 modelling can be used for predicting salt-enhancing peptides.
研究领域:
食品科学
·
生物信息学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）