INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2020
·
IF 5.162
Huifang Wang,Yisheng Zhang,Wenman Xue,Xinyu Zhang,Xiaoli Jia,Tianren Xue,Ruijie Guo,Baolong Niu,Hong Yan
In this contribution, a novel soluble and antibacterial polymer, O-xanthonyl-chitosan (CTMC-Xan), was synthesized successfully by grafting 1,3-dihydroxy-xanthone (Xan) to the side chains of O -carboxymethyl- N , N , N -trimethyl chitosan (CTMC). The chemical structure and physical properties of the polymer were analyzed by 1 H NMR, FT-IR spectra, UV spectra and XRD. The results showed that Xan could covalently bond with the carboxyl groups of CTMC by esterification at a grafting ratio of 9.1%. XRD patterns indicated that CTMC-Xan does not exhibit crystallization. The solubility tests showed that CTMC-Xan was completely dissolved and stable in neutral solution but unstable in acid or basic conditions. Moreover, it was found that the antibacterial activity against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) of CTMC-Xan was much stronger than that of Xan and CTMC, and the minimal bactericidal concentration (MBC) was 125 μg·mL −1 . Due to the enhanced solubility and antibacterial activity, CTMC-Xan could potentially serve as a desirable biomaterial for food and pharmaceutical applications .
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PubMed
高影响因子
TENSIDE SURFACTANTS DETERGENTS
·
2021
·Vol. 58
·期 6
·468-474
·
IF 1.049
Zhonghua Zuo,Ming Zhou,Mao Liao,Pengao Peng,Jingfeng Zhang
Surfactants are very often used in tertiary oil production. However, the conventional surfactants cannot be used in high salinity reservoirs of tertiary oil production because the high salinity leads to the deactivation of the surfactants. Gemini sulpho-betaine surfactants have been developed to meet the requirements of tertiary oil production in such reservoirs. In this study, the Gemini sulphobetaine surfactant (bis{[(N-methyl-N-(3-alkoxy-2-hydroxy)propyl-N-(3-sulfonate)propyl]methylene}) was prepared by etherification, ring opening reaction and sulfonation reaction with decyl alcohol, epichlorohydrin, N,N’-dimethyl ethylene diamine and 1,3-propanesultone. The experimental conditions obtained are: the ratio of 1,3-propanesulfonic acid lactone to tertiary amine intermediate = 2.3 : 1, reaction temperature = 70°C and reaction time = 11 h. The analysis of the infrared spectrum showed that the structure of the synthesised substance corresponds to that of a Gemini sulphobetaine surfactant. The chemical shifts of the groups were determined by 1 HNMR structural characterisation of the products. The surface tension, emulsifying properties, foaming properties and wetting properties were investigated. The results showed that the surfactant has good foaming properties and good compatibility in a high salt environment.
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高影响因子
MACROMOLECULES
·
2023
·
IF 5.5
Xinyan Yu,Yong Wang,Yutong Dong,Ning Zhao,Lifeng Zhang,Sunting Xuan,Zhengbiao Zhang
N-Methyl peptides, which are widely found in nature, have emerged as an intriguing material in both polymer science and the biomedical field. The inefficient synthesis of N-methyl peptides, however, has greatly impeded the progress toward their structure–property investigation and applications. Here, we report an efficient, moisture-tolerant, primary amine-initiated, and acetic acid-catalyzed ring-opening polymerization of enantiomerically pure N-methyl-α-amino acids N-carboxyanhydrides, yielding well-defined, stereoregular, and structurally diverse N-methyl polypeptides. The concentration of the acetic acid, polarity of solvents, and stiffness of polymer chains were found to be crucial to the rate of the polymerization. The acetic acid was proposed to activate the monomer through hydrogen bonding interaction, promote the release of CO2, and form an acid–base equilibrium with the secondary amine chain end. The obtained N-methyl polypeptides exhibited stable helix structures, revealing chain stiffness, consistent with the high glass transition temperatures (>250 °C) from DSC measurements. Moreover, preliminary studies indicated that N-methyl polypeptides are nontoxic both in vitro and in vivo and are enzymatically stable toward trypsin treatment. Together, this study provides a mild and efficient method for the preparation of N-methyl polypeptides, opening avenues for their further structure–property investigation and potential applications.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Weiming Xiang,Qiuyi Ji,Chenmin Xu,Yang Guo,Yazi Liu,Dunyu Sun,Wenwu Zhou,Zhe Xu,Chengdu Qi,Shaogui Yang,Shiyin Li,Cheng Sun,Huan He
A novel Co 3 O 4 /g-C 3 N 4 /Bi 2 O 2 CO 3 (BCCN) photocatalyst with p-n/n-n heterojunction was synthesized through a solvent-thermal method. The degradation efficiency of 20 mg/L iohexol reached 94 % in 60 min ( k app =0.0417 min −1 ) in BCCN/light/PS system, which was 2.8 and 6.5 times higher than systems of BCCN/light ( k app =0.0150 min −1 ) and BCCN/PS ( k app =0.0064 min −1 ). The g-C 3 N 4 addition lowered conduction band of the prepared material to produce superoxide radicals, activate persulfate and further prevent the recombination of photoelectrons and holes. Superoxide radicals and singlet oxygens were dominant radicals for iohexol degradation. Besides, persulfate could act as electron acceptor to enhance efficiency of electron transfer. The interaction between sulfate, superoxide and hydroxyl radicals improved singlet oxygens production. Furthermore, theoretical calculation and liquid chromatography mass spectrometry were performed to analyze degradation pathway of iohexol in the system. Ultimately, the BCCN/light/PS system can provide a new method to degrade organic pollutants in aquatic environments.
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TETRAHEDRON
·
2026
·
IF 2.1
Long Yao,Nan Wang,You Zi
A general and mild strategy for the regioselective synthesis of N-alkenyl 2-pyridones via N–C(β) bond formation is reported. Using readily available β-iodovinylsulfones as alkenylating agents, the reaction affords a diverse array of products in moderate to high yields with moderate to excellent Z -selectivity. Various 2-pyridones and β-iodovinylsulfones bearing different functional groups are well tolerated. Notably, this protocol provides an alternative to conventional N–C(α) bond-forming approaches. Gram-scale experiments demonstrate the practical applicability and scalability of this transformation.
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高影响因子
Colloids and Interfaces
·
2025
·Vol. 9
·期 5
·67
·
IF 3.2
Zhongwei Huang,Na Du,Wanguo Hou
The surface tensions (σ) of binary solutions of diiodomethane (DIM, 1)–furfural (FA, 2), DIM (1)–N,N-dimethylformamide (DMF, 2), and FA (1)–DMF (2) were determined at 25 °C over the entire bulk composition range, and the surface adsorption behavior was analyzed using the surface aggregation adsorption (SAA) model proposed recently. In particular, by combining the SAA model with the Gibbs adsorption equation, the changes in the Gibbs surface excess (Γ2) and the adsorption layer thickness (τ) with the bulk composition (x2,b) were investigated. The SAA model combined with the modified Eberhart model can well describe theσ-isotherms of the three binary solutions. The surface adsorption trends of component 2 in DIM–FA, DIM–DMF, and FA–DMF decrease in turn. The change trends of Γ2andτwithx2,bare dependent on the SAA model parameters, namely, the adsorption equilibrium constant (Kx) and the average aggregation number (n). With an increase inx2,b, Γ2continuously increases whenKx< 2v1/[n(2n− 1)v2] (wherev1andv2are the partial molar volumes of components 1 and 2, respectively); otherwise (i.e.,Kx≥ 2v1/[n(2n− 1)v2]), Γ2initially increases and then decreases, showing a maximum on the Γ2-isotherm. Whenn≥ 1,τgradually decreases with an increase inx2,b; otherwise (i.e.,n< 1),τinitially increases and then decreases, showing a maximum on theτ-isotherm. An increase in the adsorption trend leads to a decrease in both Γ2andτ. This work provides a better understanding of the surface adsorption behavior of liquid mixtures.
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高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lin-Chao Yang,Quan Zhou,Jin-Qiu Liu,Zhuo Wang,Yue-Chan Song,Wen-Wen Wu,Peng Liu
Extensive studies on TiO 2 -based colossal permittivity (CP, dielectric constant ε’ >10 3 ) materials have focused on the cation doping of metal elements; however, little attention has been paid to nonmetallic dopants. Compared to metallic elements, nonmetallic atoms with small radii and high activities, such as H, C, B, and N, can be used as anion-doping elements. Their incorporation into the TiO 2 lattice includes interstitial and substitutional doping, which can influence the bandgap of TiO 2 and its electron transport performance differently, thereby exhibiting considerable potential in TiO 2 -based applications. In this study, different N-containing compounds (BN and NH 4 Cl) were doped into rutile TiO 2 , while homogeneous ceramics of single-phase rutile TiO 2 were prepared via solid-state sintering. The effects of co-doping N, Cl, and N, B on the dielectric properties of rutile TiO 2 ceramics were investigated. While N and Cl doping showed no considerable effect on the dielectric properties of rutile TiO 2 ceramics, the co-doping of N and B doping in rutile TiO 2 considerably increased the dielectric constant to >10 4 with suppressed tan δ in a wide frequency range from 1 kHz to 10 MHz. These ceramics exhibited excellent frequency stability (up to 100 MHz) and temperature stability (153–513 K), which outperforms most reported transition metal co-doped TiO 2 ceramics, thereby highlighting the untapped potential of the non-metallic dopants in enhancing dielectric materials.
研究领域:
材料科学
·
电子工程
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Ailin Gao,Yang Yang,Changchao Jia,Jian Cui,Bo Wang,Yehai Yan
For the total heat exchange membrane, there is a compromise effect between the moisture permeability and the gas barrier. To overcome this challenge, a new type of total heat exchange membrane was proposed involving a porous polyethylene (PE) membrane and a hydrophilic poly (N, N-dimethyl acrylamide) (PDMAA) hydrogel. A dense PE/PDMAA composite membrane was fabricated via an in situ photoinitiated free-radical polymerization and cross-linking reaction through a pre-permeation of N, N-dimethyl acrylamide (DMAA) monomers in the porous structure of the PE membrane. In this study, we systematically investigated the effect of varying amounts of PDMAA filler on membrane morphology, hydrophilicity, stability, mechanical properties, water vapor transmission rate, gas barrier property, and total heat exchange efficiency. These results demonstrate that a tight, stable PE/PDMAA hybrid membrane with an interlocked structure has been created. Water vapor diffusion channels and an efficient carbon dioxide (CO 2 ) barrier were successfully constructed through the introduction of a cross-linked PDMAA hydrogel. Improvements in water vapor transmission rate and reduction in CO 2 transmission rate were achieved simultaneously with increasing PDMAA filling amount. Excellent mechanical properties and hybrid stability were also observed for the composite membrane obtained. This work provides a novel total heat exchange membrane with convenient production process, low cost and high durability characteristics.
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高影响因子
JOURNAL OF POLYMER SCIENCE
·
2022
·Vol. 61
·期 6
·491-502
·
IF 3.046
Lidong Cao,Xingzhong Fang,Guofei Chen
High imidization temperature of polyimides (PIs) brings great restriction to the applications in electronic industry. In this study, N,N ′-carbonyldiimidazole (CDI), a novel low-temperature imidization accelerator with the unique dual function of catalyst and dehydrating agent, was researched to solve this problem. PIs synthesized from 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 4,4′-oxydianiline were researched as the main object on method A and method B, two preparation methods of PIs, by introduction of CDI, which was found that the PIs prepared by method A achieved complete imidization and basically had no residual CDI and N,N -Dimethylacetamide at 180 °C under vacuum, while the completely imidized PIs prepared by method B were also obtained at 40 °C. Even prepared at low temperature, the PI films with adding CDI both showed satisfactory thermal and mechanical properties, especially in reducing coefficient of thermal expansion. In addition, the universality of the reaction between CDI and poly(amic acid) were also verified by other soluble PI systems. All these results prove the superior performance of CDI in lowering imidization temperature, showing great potentials in low-temperature cured PIs. Graphical
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高影响因子
Chemical Engineering and Processing-Process Intensification
·
2022
·
IF 4.264
Yuqi Zheng,Yang Jin,Nan Zhang,Dong Wang,Yang Yang,Meng Zhang,Guohui Wang,Shaoxiang Lee,Wenjuan Qu
A Bipolar membrane electrodialysis (BMED) was performed to achieve efficient production of N, N-dimethylglycine (DMG) from dimethylglycine hydrochloride. And the two-compartment cell configuration (BP-A) was used to avoid the amino acid macromolecules migrating through the membrane resulting in membrane fouling. Several experiment parameters including current density, initial dimethylglycine hydrochloride concentration and flow rate were discussed and compared. The results indicated that the optimal operation condition was at the current density of 50 A/m 2 , feed mole concentration of 0.3M and flow rate of 15L/h. Under the optimal condition, the energy consumption was 0.45 kWh/kg, the current efficiency was 65% and the recovery ratio for DMG reached 98% by calculation. In addition, the membrane fouling after experiments was conducted and further analyzed. It was observed that there was no appreciable change on the membrane during the BMED process by the SEM images and FTIR spectra. These results show that the harm of BMED process to membranes could be ignored. BMED method has the advantages of high purity, no by-products, low energy consumption and environmental friendliness. And this study can broaden the application of electrodialysis in the purification and preparation of macromolecular amino acids.
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高影响因子
COMBUSTION AND FLAME
·
2023
·
IF 4.4
Du Wang,Zhen-Yu Tian,Zhi-Hao Zheng,Wang Li,Ling-Nan Wu,Jiu-Jie Kuang,Jiu-Zhong Yang
As a polar solvent , N, N-Dimethylformamide (DMF) is a potential source of volatile organic compounds during industrial processing. The potential energy surface and pressure-dependent rate coefficients of DMF primary and secondary thermal decomposition were theoretically investigated by automatic ab initio calculations. A singlet aminohydroxycarbene route generating CO is found to be the most energetically favored channel among the unimolecular initiation reactions with a tight transition state. A kinetic model was proposed for DMF pyrolysis prediction and validated against the speciation data newly obtained from synchrotron vacuum ultraviolet photoionization mass spectrometry in a flow reactor within 773 K–1048 K and literature data in a jet stirred reactor within 450 K–900 K at atmospheric pressure. Satisfactory agreements were obtained for the major intermediates and products, but the model failed to capture the formation of some oxygenated compounds, possibly due to the missing reaction pathway for bimolecular addition. During pyrolysis , DMF is mainly consumed by the hydrogen abstraction reaction as the relatively high C N bond energy hinders the barrierless homolytic cleavage. Unlike aldehydes where the carbonyl site is favored, H-abstraction from DMF methyl sites is prevalent, although the acylamino group readily undergoes decarbonylation and β-scission forming oxygenated and nitrogenous parts. Consequently, CO and HCN are the major pyrolysis products. Besides, by incorporating essential high temperature kinetics, extended validation was conducted against the available intermediate temperature autoignition delay times (1000–1350 K, 2 bar) and laminar burning velocity data, and the reason for the discrepancy between the model prediction and experiments was inferred according to the sensitivity analyses.
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高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2017
·
IF 1.591
Liuchen Zhao,Hui Zhang,Wanxu Wang,Guoyong Wang
Surface tension, steady-shear viscosity, and antibacterial activity were investigated when salicylate 2-hydroxybenzoate (NaSal) was added to the micellar solution of N-hexadecane-N-methylpyrrolidinium bromide (C16MPB). It was found that for the mixed system, two flat portions appeared on the surface tension curve with the existence of NaSal in the low-concentration range. The equilibrium contact angle of droplets was decreased with the increase of NaSal concentration. In addition, the steady-shear viscosity abruptly increased with the increase of the concentration of mixture, even if the concentration of NaSal is low. However, this high-viscosity solution exhibited temperature-sensitive property, and white precipitate formation below 18°C. Moreover, the bactericidal capability of C16MPB was affected severely by the mixture of high concentration. All of these features could be attributed to the special interactions between C16MPB and NaSal molecules, among which intramolecular hydrogen bonding of NaSal plays a key role, which have been primely demonstrated by the package of Gaussian09 in this work.
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高影响因子
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