SOLID STATE IONICS
·
2018
·
IF 2.751
Mingzhao Xu,Mingyue Gang,Li Cao,Xueyi He,Yimeng Song,Zhongyi Jiang,Hong Wu,Yanlei Su
Anion-exchange membranes (AEM) are prepared from chloromethylated poly(ether ether ketone) (CMPEEK), which is quaternized by N , N , N ′, N ′-tetramethyl-1,4-phenylenediamine (TMPD) and 1-methylimidazole using a two-step method. TMPD can not only improve the mechanical properties but also provide more ion exchange groups and improve the availability of quaternary ammonium (QA) groups. By varying the amount of TMPD in the membrane casting solution , the comprehensive properties of the membranes are optimized and intensified. The anion conductivity is increased from 0.028 S cm −1 of the imidazolium functionalized poly (ether ether ketone) (ImPEEK) control membrane to 0.042 S cm −1 of the TMPD/ImPEEK membrane with a TMPD content of 5 wt%. Meanwhile, a 31.5% increase in ultimate tensile strength and a 27.8% increase in Young's modulus of the TMPD/ImPEEK membrane are achieved. This study exploited a facile approach to solving the trade-off relation between anion conductivity and mechanical properties.
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Fangbao Fu,Dongjie Yang,Bowei Zhao,Yukang Fan,Weifeng Liu,Hongming Lou,Xueqing Qiu
Heteroatom-doped porous carbon materials show promise for use as supercapacitor electrodes, but the tradeoff between surface area and the heteroatom dopant levels limits the supercapacitive performance. Here, we modulated the pore structure and surface dopants of N, S co-doped hierarchical porous lignin-derived carbon (NS-HPLC-K) via self-assembly assisted template-coupled activation. The ingenious assembly of lignin micelles and sulfomethylated melamine into a magnesium carbonate basic template greatly promoted the KOH activation process, which endowed the NS-HPLC-K with uniform distributions of activated N/S dopants and highly accessible nanosized pores. The optimized NS-HPLC-K exhibited a three-dimensional hierarchically porous architecture composed of wrinkled nanosheets and a high specific surface area of 2538.3 ± 9.5 m 2 /g with a rational N content of 3.19 ± 0.01 at.%, which boosted the electrical double-layer capacitance and pseudocapacitance. Consequently, the NS-HPLC-K supercapacitor electrode delivered a superior gravimetric capacitance of 393 F/g at 0.5 A/g. Furthermore, the assembled coin-type supercapacitor showed good energy-power characteristics and cycling stability. This work provides a novel idea for designing eco-friendly porous carbons for use in advanced supercapacitors.
研究领域:
材料科学
·
电化学
·
能源存储
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DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2010
·
IF 3.167
Tao Xu,Meihua Xin,Mingchun Li,Huili Huang,Shengquan Zhou
O -Methyl free N , N , N -trimethyl chitosan (TMC) was synthesized by treating chitosan with formic acid and formaldehyde firstly, followed by methylation with CH 3 I. TMC was further carboxymethylated by monochloroacetic acid to obtain N , N , N -trimethyl- O -carboxymethyl chitosan (TMCMC). The products were characterized by FTIR, 1 H NMR, EA and TGA. Their antibacterial activity was investigated against Staphylococcus aureus and Escherichia coli . The antibacterial activity of TMC decreased as the degree of substitution increased at pH 5.5. But the structure activity relationship was reversed at pH 7.2. TMCMC acted weaker than TMC, and its activity decreased as the degree of carboxymethylation increased. The experimental results showed that the activity of N , N , N -trimethyl amino group was weaker than other non-quaternized amino groups, and carboxymethylation didnot enhance the antibacterial activity directly.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Liju Bai,Shijian Lu,Qizheng Zhao,Linlin Chen,Yingjie Jiang,Chunxiao Jia,Siming Chen
Non-aqueous biphasic solvents, which combine the advantages of a non-aqueous absorbent and biphasic absorbent, have attracted increasing attention for CO 2 capture because of their great potential to reduce the energy consumption. This study proposed a non-aqueous N -ethylethanolamine (EMEA)/ N , N -diethylethanolamine (DEEA)-based liquid–liquid biphasic absorbent with p -xylene (PX) to replace 45–65 % of DEEA. The biphasic absorbent comprising 30 wt% EMEA + 5 wt% DEEA + 65 wt% PX (30E5D65P) had the best phase-change behaviour. In this absorbent, 98.8 % of the absorbed CO 2 was in the lower phase of the solvent, with a volume percentage of 35.1 %. This absorbent also showed the best CO 2 -desorption performance, with almost double the CO 2 -desorption amount and maximum CO 2 -desorption rate compared with those achieved using the 30 wt% EMEA + 70 wt% DEEA (30E70D) non-aqueous absorbent. The regeneration energy of 30E5D65P was 1.71 GJ∙t −1 CO 2 , which was reduced by 31 % and 55 % compared with that of the non-aqueous 30E70D absorbent and the aqueous 30 wt% monoethanolamine absorbent, respectively. 13 C NMR analysis and quantum chemical calculations showed that carbamate and PX have a better separation effect than that of EMEA and DEEA, owing to the presence of both polarity and hydrogen bonding. PX with low polarity was beneficial for the separation of carbamate. The carbamate interacted with (protonated) EMEA, (protonated) DEEA and carbamic acid through hydrogen bonds, resulting in the appearance of these components in the lower phase. The carbamate had no hydrogen bond self-aggregation, which may be the reason why there was no crystal precipitation.
研究领域:
化学工程
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环境科学
·
能源技术
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高影响因子
Nanoscale
·
2017
·Vol. 9
·期 47
·18940-18950
·
IF 7.367
Huabin Chen,Wenxia Liu,Bin Hu,Zhuozhuo Qin,Hong Liu
The development of full-spectrum photocatalysts active in the near-infrared (NIR) region has gained increasing attention in the photodegradation of organic pollutants. Herein, we designed a full-spectrum photocatalyst with strong NIR photoactivity based on the synergy of Er3+-doped ZnO-CuO-ZnAl2O4 multi-phase oxides (Er3+-doped Zn/Cu/Al-MPO) via the formation of n–p–n double heterojunctions. The photocatalyst was prepared by synthesizing nanosheets of a Zn/Cu/Al/Er hydrotalcite-like compound (Zn/Cu/Al/Er-HLC) with a co-precipitation method followed by calcination of the nanosheets at 800 °C. The as-prepared Er3+-doped Zn/Cu/Al-MPO inherits the nanosheet morphology of Zn/Cu/Al/Er-HLC, and displays over-doubled photoactivity in the entire ultraviolet (UV), visible and NIR regions compared to undoped Zn/Cu/Al-MPO. The excellent photocatalytic activity of Er3+-doped Zn/Cu/Al-MPO, especially its strong NIR photoactivity, is ascribed to its Er3+-doped CuO-involved multi-crystalline phase heterostructure, i.e., n–p–n double heterojunctions, which does not only offer an enhanced NIR absorption but also promotes the separation of photogenerated charge carriers. Importantly, the synergy of all the parts of the n–p–n double heterojuctions plays an important role in interface band structure regulation for the enhancement of the photocatalytic properties of Er3+-doped Zn/Cu/Al-MPO. This work has demonstrated the feasibility of utilizing hydrotalcite-like precursors in the design of full-spectrum photocatalysts active in the NIR region.
研究领域:
材料科学
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环境科学
·
化学工程
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MACROMOLECULAR MATERIALS AND ENGINEERING
·
2019
·Vol. 304
·期 11
·1900309
·
IF 3.038
Changzhuang Bai,Qiuhua Huang,Xiao Zhang,Xiaopeng Xiong
Tough hydrogels receive continuous attention because of their promising applications in many fields. Herein, tough hydrogels of poly ( N , N -dimethylacrylamide) (PDMAA)/alginate (SA) are prepared, with interpenetrating network (IPN) and of PDMAA/chitosan (CS) with semi-IPN microstructure, respectively. The toughening of the hydrogel by incorporating natural polymers is studied by compressing tests and dynamic mechanical analyses. Moreover, cyclic load–unload compressing of the two types of hydrogels are performed at low strains and under relatively high strains, in order to compare their strength and anti-fatigue properties. The results indicate that the mechanical strength can be markedly improved upon addition of the natural polymers, and the IPN hydrogel of PDMAA/SA reveals much higher mechanical performances but is less stable. However, the semi-IPN hydrogel of PDMAA/CS displays excellent anti-fatigue stability, but with relatively low strength. Swelling tests, scanning electron microscopy, and Fourier transform infrared spectroscopy are carried out to study the microstructures of the hydrogels, which are carefully analyzed to understand the difference in mechanical performances of those hydrogels. The results suggest that the presence of sacrificial unit and higher chain density in the IPN are helpful for toughening hydrogels, while the semi-IPN network is beneficial to improve the energy dissipation efficiency.
研究领域:
材料科学
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高分子科学
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生物医学工程
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软材料
·
聚合物力学性能
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高影响因子
DRUG DEVELOPMENT AND INDUSTRIAL PHARMACY
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2018
·
IF 1.883
Jie Liao,Xiaoting Ren,Bowen Yang,Hou Li,Yuexin Zhang,Zongning Yin
Lumbrokinase (LK) has strong fibrinolytic and thrombolytic activities, but it has a short half-life, can be easily inactivated, and may cause hemorrhage as a side effect. This study develops a potential thrombolytic therapy by fabricating N,N,N-Trimethyl Chitosan (TMC) nanoparticles modified with the cyclic Arg-Gly-Asp-Phe-Lys peptide (c-RGD) and loaded with LK (i.e. c-RGD-LK-NPs). The binding of c-RGD to platelet membrane GPIIb/IIIa receptors is expected to enable targeted delivery of the c-RGD-conjugated TMC to the thrombus. The synthesized c-RGD-LK-NPs had a mean particle size of 232.0 nm, zeta potential of 19.8 mV, entrapment efficiency of 52.7% ± 2.5%, and loading efficiency of 17.4% ± 0.65%. Transmission electron microscopy showed that they were generally spherical. The c-RGD-LK-NPs gave a cumulative in vitro LK release of 80.6% over 8 h, and the activity of LK was close to 80%, indicating that the nanoparticles protected the activity of LK. In vitro blood clot lysis assays were carried out and in vivo thrombolysis effect was tested in Sprague-Dawley rats carotid artery thrombus model. In all cases, the c-RGD-LK-NPs showed superior performance compared with the free LK and the unmodified TMC nanoparticles loaded with LK. The c-RGD-LK-NPs reagent is expected to be potentially useful in treating thromboembolic diseases.
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DOI
PubMed
高影响因子
MACROMOLECULES
·
2013
·
IF 5.521
Meihan Dan,Yang Su,Xin Xiao,Shentong Li,Wangqing Zhang
A new family of the thermo-responsive polymers based on poly[N-(4-vinylbenzyl)-N,N-dialkylamine] with the pendent amine group as well as the doubly thermo-responsive triblock copolymer were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. These polymers showed the lower critical solution temperature (LCST) and/or the upper critical solution temperature (UCST) in alcohol and in the alcohol/water mixture. The polymer molecular weight, the polymer concentration, the cosolvent/nonsolvent and the deuterated solvent affecting the LCST and/or UCST were investigated, and their great influence on the LCST/UCST was demonstrated. The origin of the phase transition of poly[N-(4-vinylbenzyl)-N,N-dialkylamine] at LCST upon heating was investigated and the possible reason was proposed. The doubly thermo-responsive triblock copolymer of PVMA53-b-PVEA108-b-PVMA53 underwent phase transition at two LCST temperatures. The PVEA108 block underwent the initial phase transition at the first LCST of 32.5 °C to form core–corona micelles, and then the subsequent phase transition of the PVMA53 block took place at the second LCST of 54.5 °C to produce corona-collapsed micelles. The proposed polymers based on poly[N-(4-vinylbenzyl)-N,N-dialkylamine] are anticipated to broaden the thermo-responsive polymer range and will be useful in polymer science.
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CARBOHYDRATE POLYMERS
·
2015
·
IF 4.074
Hongqi Ren,Shuai Liu,Jixiang Yang,Xian Zhang,Hao Zhou,Jiatong Chen,Tianying Guo
A novel non-viral gene carrier based on N , N , N -trimethylchitosan (TMC) has been fabricated. First, well-defined copolymer P (PEGMA- co -DMAEMA) was synthesized through reversible addition fragmentation chain transfer (RAFT) polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and N , N -(2-dimethylamino)ethyl methacrylamide (DMAEMA). Then allyl group grafting N , N , N -trimethylchitosan (Allyl-TMC) was synthesized via the reaction between allyl bromide and hydroxyl of TMC. Finally, P (PEGMA- co -DMAEMA) and folate were ordinally grafted onto Allyl-TMC to obtain TMC- g - P (PEGMA- co -DMAEMA)-FA. In comparison with pristine chitosan, TMC- g - P (PEGMA- co -DMAEMA)-FA has achieved both better water solubility and stronger pDNA packaging ability, which can contribute to improving gene transfection. Gene delivery efficiency of a series of TMC based functional polymers with different chitosan molecular weights has been tested. The results show that 20k-TMC- g - P (PEGMA- co -DMAEMA)-FA/pDNA complex at the weight ratio of 20 achieve the highest transfection efficiency in 293 T cells. This work presents a new strategy to modify chitosan efficiently as gene carrier material.
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PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2021
·
IF 5.541
Zhen-Guo Fan,Zhen-Yu Tian,Wang Li,Zhi-Hao Zheng,Jiu-Zhong Yang
N, N-dimethylformamide (DMF) is a kind of general solvent in Li-ion industry and nitrogen-containing component of amines fuels. The trace vapor of DMF is very harmful to human and environment, which could be treated by pyrolysis. The pyrolysis of DMF was newly carried out in a flow reactor at 30 Torr within 873–1273 K. Synchrotron radiation single photoionization coupled with molecular beam mass spectrometry was employed to detect the reactants, intermediates and products. 26 species were identified and quantified. Products related to NOx, such as nitrosomethane, nitrosyl cyanide and N-methylformamide were identified. With the temperature increasing, the mole fractions of species tend to increase monotonically, while nitrosyl cyanide, ethyl radical, cyclopropane , carbon monoxide , ethanol, acetaldehyde and ethanol exhibit peak-shaped curves. Hydrogen abstractions and dissociations are the main initial pathways of DMF consumption. As the main hydrocarbon products, methane and ethylene are predominantly formed by the H abstraction reaction by methyl radical and the β-scission of ethyl radical, respectively. Carbon monoxide is mainly generated from the dissociation of DMF and its mole fraction is at the same level as the fuel DMF. HCN is the most abundant product among all the carbonitride species via H abstraction of CH 2 =NH as well as the collisions of CN with alkanes and aldehydes. These results provide a theoretical basis for further study of treating DMF in the exhaust fumes through pyrolysis and have reference value for the clean utilization of amine fuels.
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高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2021
·Vol. 331
·期 1
·241-247
·
IF 1.371
Wang J. H.,Zhao X. Y.,Shi Y.,Wan Y.,Fu H. Y.,Zheng W. F.
The reaction mechanisms and rate constants of N, N-diethylhydroxylamine (DEHA) with · OH, CO 3 − · , e aq − and · H were studied. Results show that · OH radicals oxidize DEHA by hydrogen abstraction from DEHA’s hydroxyl group to form transient (C 2 H 5 ) 2 NO · , which has an absorption maximum at 395 nm. The transient intermediates for the reactions of DEHA with CO 3 − · and e aq − , as well as protonated DEHA with · H, show no absorption peak between 300 and 800 nm. The rate constants for the reactions of DEHA with · OH, CO 3 − · and e aq − , also protonated DEHA with · H, were measured.
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ULTRASONICS SONOCHEMISTRY
·
2021
·
IF 7.491
Hanyang Gao,Kunkun Pei,Dong Lei,Guoxin Hu,Yan Chao,Aihua Meng,Hongcheng Wang,Wei Shentu
Due to the tunability in mass transfer, solvation and solubility, gas-expanded liquids show advantages over traditional organic solvents in many characteristics. Ultrasonication is a commonly used method to promote heat and mass transfer. The introduction of ultrasonic technology into the gas-expanded liquid system can promote the polymerization of polymer monomers, enhance extraction efficiency, and control the growth size of nanocrystals, etc. Although acoustic cavitation has been extensively explored in aqueous solutions, there are still few studies on cavitation in organic liquids, especially in gas-expanded liquid systems. In this article, the development of cavitation bubble cloud structure in CO 2 -expanded N, N-dimethylformamide (DMF) was observed by a high-speed camera, and the cavitation intensity was recorded using a spherical hydrophone. It was found that the magnitude of the transient cavitation energy was not only related to input power, but also closely related to CO 2 content. The combination of ultrasound (causing a rapid alternation of gas solubility) and gas-expanded liquid system (causing a decrease in viscosity and surface tension of liquids) is expected to provide a perfect platform for high-speed mass transfer.
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PubMed
高影响因子
危险品化学品经营许可证（带存储）