Frontiers of Chemical Science and Engineering
·
2022
·Vol. 16
·期 9
·1399-1406
·
IF 4.803
Feng Xing,Du Meiqing,Wei Hongbei,Ruan Xiaoxiao,Fu Tao,Zhang Jie,Sun Xiaolong
The degradation of polymeric materials is recognized as one of the goals to be fulfilled for the sustainable economy. In this study, a novel methodology was presented to synthesize multiple highly cross-linked polymers (i.e., hydrogels) through amine-thiol scrambling under mild conditions. Amine-terminated poly(ethylene glycol) (PEG-NH 2 ) was reacted with the representative conjugate acceptors to synthesize hydrogels in organic and aqueous solutions, respectively. The materials above exhibited high water-swelling properties, distributed porous structures, as well as prominent mechanical strengths. It is noteworthy that the mentioned hydrogels could be degraded efficiently in hours to release the original coupling partner, which were induced by ethylene diamine at ambient temperature through amine-amine metathesis. The recovered PEG-NH 2 reagent could be employed again to regenerate hydrogels. Due to the multiple architectures and functions in polymeric synthesis, degradation and regeneration, a new generation of “smart” materials is revealed.
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Food Analytical Methods
·
2016
·Vol. 10
·期 5
·1592-1596
·
IF 2.167
Xie Wei-Qi,Chai Xin-Sheng
This paper reports on a practical headspace gas chromatographic method (HS-GC) for rapid determination of degree of substitution (DS) in sodium carboxymethyl starch (Na-CMS). After Na-CMS was acidified by hydrochloric acid (HCl) solution, the supernatant of the solution was added to a bicarbonate solution in a closed headspace vial. Thus, the remaining HCl reacts with bicarbonate to form carbon dioxide gas and thus was measured by HS-GC. The result showed that the Na-CMS was completely converted to H-CMS within 45 min at a room temperature when a small sample size (= 0.5 g) was used by acidification pretreatment. The present method has a good measurement precision (the relative standard deviation <3.25%) and accuracy (the relative difference < 5.46%, compared to the data measured by the reference method) on the determination of DS in Na-CMS. The present method is simple, practical, and suitable for the use in the carboxymethyl starch related research and applications.
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International Journal of Minerals Metallurgy and Materials
·
2018
·Vol. 25
·期 2
·226-235
·
IF 1.261
Chen Zhi-yuan,Bian Liu-zhen,Yu Zi-you,Wang Li-jun,Li Fu-shen,Chou Kuo-Chih
Carbon deposition on nickel powders in methane involves three stages in different reaction temperature ranges. Temperature programing oxidation test and Raman spectrum results indicated the formation of complex and ordered carbon structures at high deposition temperatures. The values of I (D)/ I (G) of the deposited carbon reached 1.86, 1.30, and 1.22 in the first, second, and third stages, respectively. The structure of carbon in the second stage was similar to that in the third stage. Carbon deposited in the first stage rarely contained homogeneous pyrolytic deposit layers. A kinetic model was developed to analyze the carbon deposition behavior in the first stage. The rate-determining step of the first stage is supposed to be interfacial reaction. Based on the investigation of carbon deposition kinetics on nickel powders from different resources, carbon deposition rate is suggested to have a linear relation with the square of specific surface area of nickel particles.
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JOURNAL OF POLYMER RESEARCH
·
2020
·Vol. 27
·期 6
·1-9
·
IF 2.426
Deng Yaling,Sun Jianjun,Ni Xingya,Yu Bo
Natural joints have the hierarchical structure of bone and cartilage, providing excellent lubrication and load-carrying capacity. In our research, the hierarchical structure artificial joints of Poly Acrylic Acid (PAA)- Poly Acrylamide (PAAm) hydrogel coating and Ti6Al4V substrate were formed using a simple yet versatile method by mimicking the hierarchical structure of natural joints. The efficient lubrication at friction interfaces was achieved. The composition and microstructure were confirmed by Fourier-transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM). The hydrogel coatings were successfully prepared on the surface of Ti6Al4V substrate through the adsorption of the charged group. This hierarchical structure material exhibits the lower dynamic friction, approximately 0.085, which is much lower than bare Ti6Al4V, about 0.429. The wear on the surfaces after the tribological experiment is super-shallow and has no significant fracture area around the scratch. The PAA-PAAm hydrogel has a more uniform and compact cross-linked network porous structure, and the porous size is much smaller than PAA hydrogel. The cross-linked network porous structure is the main factor accounting for the low dynamic friction. This hierarchical structure of soft and hard improve the load-carrying ability and has the potential uses in artificial joints.
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JOURNAL OF MATERIALS SCIENCE
·
2020
·Vol. 55
·期 26
·12373-12384
·
IF 3.553
Liu Yuansheng,Liu Huitian,Huang Wenlong,Yu Yu,Dai Xiaoqian,Shan Zhongqiang
Dramatic volumetric variation and poor cyclic stability are great challenges for the practical application of Si anode in lithium-ion batteries. In this work, hierarchical microsized hard carbon-supported Si encapsulated in nitrogen-doped carbon (HC/Si@NC) composites is successfully synthesized via electrostatic self-assembly between an intrinsic negatively charged hard carbon precursor and positively charged Si nanoparticles for the first time. Resorcinol formaldehyde resin sphere synthesized through a low-cost extended Stöber method is used as the carbon core precursor to support Si nanoparticles, followed by carbon coating and carbonization process to further fix Si on the carbon core and enhance the conductivity. The hierarchical structure where Si nanoparticles are tightly anchored onto the carbon core can significantly alleviate the volumetric expansion of Si, and the carbon can enhance the conductivity of the composites. As a result, the as-achieved HC/Si@NC composites exhibit outstanding cycling stability and good structural integrity maintenance. The composites deliver a reversible capacity of 541 mAh g −1 with a capacity retention of 92.1% after 100 cycles at a current density of 0.2 A g −1 and a capacity of 350 mAh g −1 after 300 cycles at a higher current density of 1 A g −1 .
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JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
·
2019
·
IF 3.202
Xu Zhao,Jing Chen,Weiying Zhang,Chengdui Yang,Xiaoxiao Ma,Sichun Zhang,Xinrong Zhang
Lipids exert substantial influences on vertebrate embryogenesis, but their metabolic dynamics at detailed structural levels remains elusive, primarily owing to the lack of a tool capable of resolving their huge structural diversity. Herein, we present the first large-scale and spatiotemporal monitoring of unsaturated lipids with C=C specificity in single developing zebrafish embryos enabled by photochemical derivatization and tandem mass spectrometry (MS). The lipid isomer composition was found extremely stable in yolk throughout embryogenesis, while notable differences in ratios of C=C location (e.g., PC 16:0_16:1 (7) vs. 16:0_16:1 (9)) and fatty acyl composition isomers (e.g., PC 16:1_18:1 vs. 16:0_18:2) were unveiled between blastomeres and yolk from zygote to 4 h post fertilization (hpf). From 24 hpf onwards, lipid isomer compositions in embryo head and tail evolved distinctively with development, suggesting a meticulously regulated lipid remodeling essential for cell division and differentiation. This work has laid the foundation for functional studies of structurally defined lipids in vertebrate embryology.
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PubMed
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 29
·期 13
·18680-18688
·
IF 4.223
Sun Wenjing,Hu Xiaoyu,Xiang Yuhong,Ye Nengsheng
In this work, four kinds of covalent organic framework (COF) materials (TpPa-1, TpBD, TpDT, and TFBBD) with different pore sizes or functional groups were synthesized by an ultrasonic method for the adsorption of five sulfonamides. Optimization experiments regarding the adsorption time, vortex speed, and pH were carried out to improve adsorption efficiency. In addition, kinetic and thermodynamic experiments were conducted to explore the adsorption mechanism of the sulfonamides on the different COFs. The adsorption processes of the five sulfonamides on the four COFs fit the pseudo-second-order kinetic model and Langmuir adsorption isotherm model. Additionally, pore filling, hydrogen bond interactions, and electrostatic attraction were found to be the main adsorption mechanisms.
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Frontiers of Chemical Science and Engineering
·
2023
·Vol. 17
·期 10
·1533-1543
·
IF 4.5
Xu Shengshuo,Lu Zhenying,Wang Jinling,Huang Guangtuan,Wang Hualin,Yang Xuejing
Iron oxychloride (FeOCl) is a unique layered material with tunable electronic properties. The conventional synthetic route of chemical vapor transition involves a thermodynamics-driven gas–solid interfacial reaction which often generates macroscopic crystals with stable facets. In this study, through analyzing the effects of the synthetic parameters on the FeOCl synthesis, we discovered the dominant contribution of the α -Fe 2 O 3 precursors on the chemical property of the FeOCl product, and subsequently developed a highly-controllable synthetic route of tailoring the FeOCl structures into small sizes and exposed high-energy facets via a facile and scalable mechanical-chemical approach. The synthesized products could be systematically tuned by the ball-milling conditions of the α -Fe 2 O 3 precursors. With increased milling time, the FeOCl crystallites demonstrated reduced sizes and more exposed (110) facets. Intriguingly, these small-sized FeOCl catalysts exhibited much faster Fenton-like kinetics than the pristine macroscopic FeOCl materials. Specifically, FeOCl catalysts with a 12-hour milling time showed nearly 39 times higher efficiency toward phenol degradation than the pristine FeOCl. The structure-reactivity relationship was further elucidated using the combinatory analysis via density functional theory calculation, electron paramagnetic resonance and radical quenching probe experiments. This work provides a rationale for tailoring the surface structures of FeOCl crystallites for potential applications in environmental catalysis.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2017
·Vol. 131
·期 2
·1361-1371
·
IF 1.953
Wu Cheng-jie,You Jin-zong,Wang Xue-jie
The thermal decomposition of famciclovir (FCV) was measured with thermogravimetry, differential scanning calorimetry, and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. The IR spectra, high-performance liquid chromatography, and liquid chromatography–mass spectrometry of FCV and the residues of its thermal decomposition at various temperatures were determined. The molecular bond orders were calculated using an ab initio method from the GAMESS program of quantum chemistry. The mechanism of thermal decomposition for FCV was discussed. The kinetic parameters for thermal decomposition such as activation energy E
a and the pre-exponential factor A were obtained using the Ozawa method. The prospective lifetime of FCV was estimated using the Dakin equation. The results indicated that the thermal decomposition of FCV is a two-step process. The initial decomposition temperature in either nitrogen or air is about 205 °C. The decomposition of FCV does not go through 2-amino-purine stage, 2-amino-purine, and alkane chain segment both decompose simultaneously during the first stage. For decomposition in nitrogen, the E
a and A for the initial thermal decomposition are 107.8 kJ mol −1 and 2.19 × 10 9 min −1 , respectively. For decomposition in air, the corresponding E
a and A are 96.4 kJ mol −1 and 1.45 × 10 8 min −1 , respectively. The FCV has good thermal stability under routine temperature.
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MICROCHIMICA ACTA
·
2022
·Vol. 189
·期 2
·1-10
·
IF 6.408
Wu Xia,Meng Xufeng,Hou Baoxiu,Sun Zhong,Zhang Yunyi,Li Ming
A smartphone-assisted fluorescence color sensing system for rapid, convenient, and on-site detection of copper ions was developed. The ratiometric fluorescence sensor was fabricated by using silica-coated blue-light-emitting carbon dots and surface-grafted red-light-emitting cadmium-telluride quantum dots. After exposure to Cu 2+ in 20 s, the red fluorescence was quenched obviously, while the blue fluorescence remained unchanged, and the sensor color changes continuously from red to blue under the ultraviolet lamp. The concentration (50–1200 nM) of copper ions could be measured by the fluorescence spectrum (excitation at 360 nm, dual-emission at 441 and 640 nm) with a detection limit of 7.7 nM. The fluorescence colors were converted to digital RGB values to calculate the concentration of copper ions by a smartphone with a detection limit of 9.6 nM. The method was applied to detecting copper ions spiked in real samples with recovery from 97.9 to 108.0% and RSD from 3.8 to 8.9%. Thus, this convenient and practical fluorescence color sensing system presents a new strategy for rapid, sensitive, and on-site determination of copper ions in environmental or biological samples. Graphical abstract
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MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 9
·1-10
·
IF 5.705
Khan Md. Zaved H.,Liu Xiaoqiang,Tang Yunfei,Zhu Jinhua,Hu Weiping,Liu Xiuhua
A glassy carbon electrode (GCE) was modified with poly(L-arginine) (P-Arg), reduced graphene oxide (rGO) and gold nanoparticle (AuNP) to obtain an electrode for simultaneous determination of dopamine (DA), serotonin (5-HT) and L-tryptophan (L-Trp) in the presence of ascorbic acid (AA). The modified GCE was prepared via subsequent ‘layer-by-layer’ deposition using an electrochemical technique. The surface morphology of the modified electrode was studied by scanning electron microscopy, and electrochemical characterizations were carried out via cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode showed excellent electrocatalytic activity toward DA, 5-HT and L-Trp at pH 7.0. Figures of merit for the differential pulse voltammetric reponse are as follows: (a) Response to DA is linear in two intervals, viz. 1.0–50 nM and 1.0–50 μM DA concentration range, the typical working voltage is 202 mV (vs. Ag/AgCl), and the detection limit is 1 nM (at an S/N ratio of 3). For 5-HT, the respective data are 10 to 500 nM and 1.0 to 10 μM, 381 mV, and 30 nM. For L-Trp, the respective data are 10–70 nM and 10–100 μM, 719 mV, and 0.1 μM. The modified GCE is fairly selective. It was successfully applied to the simultaneous determination of DA, 5-HT, and L-Trp in spiked urine samples, and high recovery rates were found.
Schematic presentation of the voltammetric sensor based on a glassy carbon electrode modified with poly(L-arginine), reduced graphene oxide (rGO) and gold nanoparticle (GCE/P-Arg/ErGO/AuNP) for simultaneous determination of dopamine (DA), serotonin (5-HT) and L-tryptophan (L-Trp).
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 35
·期 5
·924-928
·
IF 1.071
Xiang Siyuan,Meng Qingnan,Zhang Kai,Gu Yue,Liu Wendong,Yang Bai
Using dextran as both reductant and stabilizing agent, nanopetals(ZnO-Au NPs) were easily synthesized and possessed a petal-like morphology. The feature structure and size of such ZnO-Au NPs were adjustable by regulating the amount of chloroauric acid(HAuCl 4 ). Moreover, the electrochemical property of the obtained NPs was evaluated by being immobilized on the glassy carbon electrode(GCE), which performed both high sensitivity and stability in dopamine(DA) determinations. Furthermore, the as-prepared ZnO-Au NPs could also detect DA and uric acid(UA) simultaneously in the mixture without interference, indicating good selectivity and showing promising potential in biosensing.
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