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2018 Vol.39 No.5
 Published: 10 May 2018


Content
Articles: Inorganic Chemistry
Analytical Chemistry
Organic Chemistry
Physical Chemistry
Polymer Chemistry
 
Content
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2018 Vol. 39 (5): 0-0 [Abstract] ( 29 ) [HTML 1KB] [PDF 2419KB] ( 201 )   
doi:

Articles: Inorganic Chemistry
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GUO Junhui, YAN Wenfu, SHI Wei, XU Ruren
Rapid Synthesis of Aluminophosphate Molecular Sieve AlPO4-5 Under Ambient Pressure and In situ Thermogravimetric-Mass Spectroscopy Investigation of the Crystallization
2018 Vol. 39 (5): 841-848 [Abstract] ( 35 ) [HTML 1KB] [PDF 3016KB] ( 221 )   
doi: 10.7503/cjcu20180013

The crystallization behavior of the initial gels containing the structure-directing agents of triethylamine, cyclohexylamine or tetraethylammonium hydroxide under ambient pressure and autogenous pressure at elevated temperature was investigated. At 300 or 180℃ under ambient pressure, highly crystalline aluminophosphate molecular sieve AlPO4-5 was rapidly crystallized from the initial gels containing triethylamine, cyclohexylamine or tetraethylammonium hydroxide. When the same initial gels were loaded into autoclaves and heated at 180℃ in an oven, three-dimensional open-framework aluminophosphate JDF-20, layered aluminophosphate UT-5, and a mixture containing aluminophosphate molecular sieve AlPO4-5, were obtained, respectively. The crystallization process of the initial gel containing triethylamine under ambient pressure was investigated with in situ thermogravimetric-mass spectroscopy analysis. It was confirmed that the formation of aluminophosphate molecular sieve AlPO4-5 under ambient pressure was mainly occurred in the stage of 150-300℃. We found that the pressure can significantly affect the structure-directing effect of amines. This finding greatly enhanced the understanding on the formation process and crystallization mechanism of zeolites and open-framework crystals.

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GAO Jing, HUANG Keke, ZHANG Xianlong, SUN Yu, FENG Shouhua
Robust Self-assembly Properties of Glyceryl Decanoates Synthesized Under Wetting and Drying Cycles
2018 Vol. 39 (5): 849-854 [Abstract] ( 31 ) [HTML 1KB] [PDF 3648KB] ( 205 )   
doi: 10.7503/cjcu20170857

Nonenzymatic dehydration reactions of decanoic acid with glycerol has been reported to occur under mimicked prebiotic conditions at near neutral pH, yielding more evolved membrane precursor compound glyceryl decanoates. Two isomers of glyceryl monodecanoate were the main products after the condensation reactions, and the yield of glyceryl monodecanoates could be increased to 4.7% with temperature rising to 90℃. Vesicles were observed when the mixture after reactions was rehydrated. Experiments demonstrate that trace glyceryl decanoates produced in the mixture play a great role in robust self-assembly process, it is the existence of such lipid products that makes a lower critical vesicle concentration. Meanwhile, organic compounds have been encapsulated during the self-assembly of vesicles, so membranous structures provid a place for organic compounds to exist stably. The dehydration reactions at near neutral pH, followed by rehydration, are suitable for increasing protocell membrane stability to environment. It implies that the condensation reaction is plausible for yielding more complex amphiphiles and the appearance of membrane structures on the early earth.

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LI Kaifeng, WU Dan, CHEN Yanwei
Effect of Copper Doping on the Growth and Optical Properties of Au Nanorods
2018 Vol. 39 (5): 855-860 [Abstract] ( 34 ) [HTML 1KB] [PDF 4150KB] ( 185 )   
doi: 10.7503/cjcu20170829

In this paper, copper doped gold nanorods(Cu-Au NRs) were prepared by gold-copper blending method. The plasmon resonance absorption and morphological changes of Cu-Au NRs were investigated. The morphology, aspect ratio and optical properties of Cu-Au NRs were effectively controlled by adjusting the amount of Cu ions during crystal growth process. Finally, the photothermal conversion and Raman enhancement properties of Au NRs and Cu-Au NRs were investigated. The results show that copper ion doping could effectively control the morphology and the growth of Au NRs. The photothermal conversion efficiency of Cu-Au NRs is obviously lower than that of the Au NRs, but the surface enhanced Raman properties of Cu-Au NRs are better than that of Au NRs.

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ZHAO Changjiang, LIU Xin, TIAN Li, ZHAO Lun
Synthesis, Structure and Electrochemical Properties of Metal Cobalt Complexes with Interpenetrating Structures
2018 Vol. 39 (5): 861-868 [Abstract] ( 47 ) [HTML 1KB] [PDF 5871KB] ( 190 )   
doi: 10.7503/cjcu20170650

Using multidenate 4,4'-(phenylazanediyl)dibenzoic acid(H2L) and 1,3-bis(imidazol-l-yl)benzene(B), 3,5-bis(imidazol-l-yl)pyridine(bimp) or 1,4-bis(imidazol-l-yl)benzene(B') as ligands under solvothermal conditions, three new metal-organic frameworks with interpenetrating structure, {[CoLB]·H2O}n(1), {[Co2L2(bimp)0.5]·3H2O}n(2) and {[Co2L2B'2]·2DMF}n(3), were synthesized. The complexes were characterized by single-crystal X-ray diffraction(XRD), thermal analysis and powder X-ray diffraction(PXRD). Complexes 1-3 all crystallize in the monoclinic system, with C2/c(complex 1), P2/n(complex 2) and P21(complex 3) space group, respectively. In complexes 1 and 3, Co2+ forms a tetracoordinate geometry, whereas it forms a five-coordinated geometric configuration and exists as a dual-core paddle-shaped structural unit[Co2(CO2)4] in complex 2. Complexes 1 and 2 give a 2-fold interpenetrating three-dimensional(3D) supramolecular networks, while complex 3 exhibits a 4-fold interpenetrating 3D framework. The results of electrochemical studies show that complexes 1-3 are electrochemically active substances with good electrochemical reversibility.

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SUN Riyong, CHEN Zeyu, YE Yanchun, CHEN Mingxian, TANG Huaijun, WANG Kaimin, WANG Zhengliang
Bis(2-phenylpyridine)(2, 2'-bithiazole)iridium(Ⅲ) Hexafluorophosphate: Synthesis and Application in Neutral/Warm White Light-emitting Diodes
2018 Vol. 39 (5): 869-875 [Abstract] ( 61 ) [HTML 1KB] [PDF 1841KB] ( 34 )   
doi: 10.7503/cjcu20170608

A novel orange cationic organic iridium(Ⅲ) complex,[(ppy)2Ir(btz)] PF6, was synthesized using IrCl3·3H2O as iridium(Ⅲ) source, 2-phenylpyridine(ppy) as main ligand and 2,2'-bithiazole(btz) as auxiliary ligand. After the mixture of aforementioned three compounds was refluxed in glycol for 24 h, an ion exchange reaction was made with an aqueous solution of NH4PF6 for providing target complex. The correlated color temperature(CCT) of white light-emitting diodes(WLEDs) fabricated by 455 nm-emitting blue GaN chip and Y3Al5O12:Ce3+(YAG:Ce, 6.0% mass ratio to silicone) obviously declined when the complex was blended in silicone and also used in these WLEDs. Before the complex was used, CCT of the YAG:Ce-based WLED was 7133 K, the luminous efficiency(ηL) was 137.1 lm/W, the color rendering index(CRI) was 79.9, and the CIE(Commission International de I'Eclairage) value was (0.31, 0.31). When[(ppy)2Ir(btz)] PF6 was used in aforementioned WLEDs at 1.0%, 1.5% and 2.0% blending concentrations, CCT successively decreased to 5645 K(cold white light), 4072 K(neutral white light) and 3161 K(warm white light), the corresponding ηL values were 102.1, 79.1 and 66.6 lm/W, CRI were 81.9, 77.3 and 70.0, CIE values were (0.33, 0.31), (0.36, 0.33) and(0.42, 0.38), respectively. The results show that[(ppy)2Ir(btz)] PF6 is a promising orange phosphor candidate for fabricating efficient neutral/warm WLEDs.

Analytical Chemistry
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LI Yuan, WANG Tingting, LI Mei, GU Fei, BAO Changhao, HUANG Rongping, MA Jingfang, CHENG Han
Quantitative Determination of 5-HT by Electrochemical Current-correction Method
2018 Vol. 39 (5): 876-882 [Abstract] ( 35 ) [HTML 1KB] [PDF 1887KB] ( 34 )   
doi: 10.7503/cjcu20170701

In this paper, the carbon fiber ultramicroelectrode(CFUME) was prepared, after cyclic voltammetry scanning in 1.0×10-4 mol/L 5-hydroxytryptamine(5-HT), and the electrochemical behaviors of the electrode in ferricyanide and dopamine(DA) were investigated. The experimental results show that the surface of carbon fiber ultramicroelectrode has been passivated by the oxidation products of hydroxytryptamine. The carbon fiber of the deteriorated ultramicroelectrodes was burned in the faint flame to activate the surface, and the peak current ratio of the activated electrode and the new electrode in 1.0×10-3 mol/L ferricyanide solution as the correction factor, the active area of the electrode is corrected by dividing the correction factor. The experimental results show that corrected peak current and concentration of 5-HT in the range of 1.0×10-6-2.0×10-4 mol/L show a good linear relationship, and the liner regression equation is I=0.2073c+0.3074, with the related coefficient of R2=0.9962. The concentration of 5-HT was determined by this method and the recovery is 98.0%-102.4%. The method is simple and reproducible, and may be used to detect 5-HT in biological sample.

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LIANG Yunshan, HUANG Zhijun, LIU Yisong, QIAN Ziyan, YAN Biyue, WANG Zhi
Extrinsic Fluorescent Probe Analysis for Interactions Between Transgenic Insect-resistant Protein Cry1Ac and Surfactants by Pyrene
2018 Vol. 39 (5): 883-888 [Abstract] ( 33 ) [HTML 1KB] [PDF 2611KB] ( 46 )   
doi: 10.7503/cjcu20170548

The characteristics of interactions between the transgenic insect-resistant protein(Cry1Ac) and four different surfactants were investigated by fluorescence of pyrene, an extrinsic fluorescent probe. While the bovine serum albumin(BSA) was used as a reference protein. The results show that the fluorescence behavior of pyrene in RL and Tween 80 systems has a similar change pattern, and the two surfactants can be associated with proteins stably. The hydrophily and molecular polarity of Cry1Ac protein are of high values, which lead to higher I1/I3 values of pyrene when the surfactant concentration is low. After the surfactant micelles formed, neither of the proteins will change the binding sites of pyrene with the nonionic or anionic surfactants. However, CTAB has a quenching effect on fluorescence of pyrene, and it cannot form stable micelles in the presence of Cry1Ac protein.

Organic Chemistry
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WANG Jicheng, YUAN Yaofeng, ZHUO Jibin, YANG Sihan, LIN Fen
Synthesis of 2-Ferrocenyl-4, 5-diphenylimidazolium Ionic Liquids and Their Catalysis Performance for Thermal Decomposition of Ammonium Perchlorate
2018 Vol. 39 (5): 889-896 [Abstract] ( 32 ) [HTML 1KB] [PDF 1695KB] ( 39 )   
doi: 10.7503/cjcu20170708

Compounds 2a-2f were synthesized by the substitution reaction of 2-ferrocenyl-4,5-diphenylimi-dazole(1) with different halohydrocarbons. Then compounds 2a-2f were reacted with iodomethane to get compounds 3a-3f. Finally, compounds 3a-3f were exchanged anion with ammonium hexafluorophosphate to get compounds 4a-4f. All these compounds were structurally characterized by means of infrared(IR), mass spectrometry(MS), nuclear magnetic resonance(NMR), high-resolution mass spectrometry(HRMS) and X-ray crystal diffraction. Electrochemical properties of these compounds were studied by cyclic voltammetry(CV). Thermal behavior and catalytic performance for thermal decomposition of ammonium perchlorate(AP) were studied by thermogravimetric(TG) and differential scanning calorimetry(DSC). The results indicate that all the synthetic products have efficient catalytic effect on the thermal decomposition of AP. The iodized salts(3a-3f) indicate better catalytic effect than the hexafluorophosphate(4a-4f). The most outstanding compound is 3b, which makes the second decomposition stage of AP disappear, and the first stage is advanced to 270.5℃. The novel dinuclear ferrocen-based imidazolium derivatives would have great value in preparing high-burning-rate catalyst for composite solid propellants.

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HUANG Chibao, PAN Qi, CHEN Huashi, LIANG Xing, LÜ Guoling
Dicyanostilbene-derived Two-photon Fluorescence Probe for Lead Ions
2018 Vol. 39 (5): 897-903 [Abstract] ( 33 ) [HTML 1KB] [PDF 2413KB] ( 41 )   
doi: 10.7503/cjcu20170672

One-photon microscopy(OPM) uses a single photon of higher energy to excite the fluorophore, while two-photon microscopy(TPM) uses two photons of lower energy as the excitation source. Therefore, TPM has such distinct advantages as improvement of penetration depth, localized two-photon excitation, reduction of photo-damage and photobleaching, small absorption coefficient of light in tissue, and lower tissue autofluorescence. These advantages make TPM more popular among biologists. Lead is a common contaminant and has inherent toxic effects on human health and environment. Pb2+ ion contamination can affect a wide variety of diseases such as anemia, irritability, memory loss, and muscle paralysis. For these reasons, there is an urgent need to develop some effective two-photon fluorescence probes to detect trace amounts of Pb2+ ions in live cells and tissues. A novel two-photon fluorescence probe for Pb2+ derived from 4-methyl-2,5-dicyano-4'-amino stilbene as a two-photon fluorophore and bis[2-(2-aminophenylsulfanyls)ethyl] amine as a novel Pb2+ ligand was developed. The probe possessed small molecule size, large two-photon absorption cross-section(1020 GM), noncytotoxic effect, long-wavelength emission at 609 nm, large Stokes shift(209 nm), excellent photostability, moderate water-solubility, good cell-permeability and pH-insensitivity in the biologically relevant range. The probe was able to selectively detect Pb2+ ions in live cells and living tissues without interference from other metal ions and the membrane-bound probes, and its quenching constant(KsvTP) was 7.58×105 L/mol.

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GAO Fengqin, WANG Shan, WANG Yunfang, ZHAO Danlei, CUI Ru, JIANG Yucheng
Immobilization of Chloroperoxidase with Magnetic Graphene Oxide and Its Application of Decolorization of Acid Blue 45
2018 Vol. 39 (5): 904-910 [Abstract] ( 37 ) [HTML 1KB] [PDF 4171KB] ( 36 )   
doi: 10.7503/cjcu20170617

Magnetic graphene oxide(MGO) was prepared using graphene oxide(GO) and Fe3O4. Chloro-peroxidase(CPO) was immobilized via adsorption method in MGO, and the immobilization conditions, such as the temperature, time and pH value of the buffer solution, were optimized. The operating stability of immobilized CPO was studied using CPO as catalyst for the degradation of acid blue 45. The activity stability of immobilized CPO was investigated from four aspects of acid base stability, H2O2 stability, thermal stability and storage stability using CPO as catalyst for the decolorization of acid blue 45. The results show that the optimal conditions are the phosphate buffer pH=3.5, the reaction time 15 min and the temperature 15℃. TMGO{m[NH4Fe(SO4)2·12H2O]:m(GO)=10.7:1} is a better immobilized carrier than FMGO{m[NH4Fe(SO4)2·12H2O]:m(GO)=5.35:1}. And the immobilized CPO shows a better operation stability than the free enzyme. The accumulation layer of TMGO is opened at 35-50℃, leading to the loss rate of immobilized enzyme activity significantly less than that of the free enzyme. TMGO-CPO has a good reusability that the activity is still over 60% after recycling 5 times.

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YI Junming, SONG Sen, ZHANG Sheng, ZHANG Shaowei, TIAN Mengkui, NI Xinlong
Effects of Terminal Groups of Guest on the Pseudorotaxane Assembly of Cucurbit[7] uril
2018 Vol. 39 (5): 911-916 [Abstract] ( 27 ) [HTML 1KB] [PDF 2687KB] ( 33 )   
doi: 10.7503/cjcu20170607

Three guests bearing different terminal groups -COOH(G1), -CH2Br(G2) and -CH3(G3) were synthesized based on the bispyridinium ethylene-core, respectively. The experiment results suggest that Q[7] host could slip the bispyridinium ethylene-core in the assistance of the terminal moiety -COOH of G1, and[2] pseudorotaxane based molecular shuttle could be formed between G1 and Q[7], whereas the terminal moiety -CH2Br(G2) and -CH3(G3) could not help Q[7] host slip the bispyridinium ethylene-core. This could be attributed to the different electrostatic potential properties between the terminal groups of the guest and the carbonyl portals of Q[7].

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WANG Chang, CHEN Yuzhe, WU Dayong
Preparation and Photophysical Properties of Pyrene-doped Silica Fluorescent Nanoparticles
2018 Vol. 39 (5): 917-925 [Abstract] ( 29 ) [HTML 1KB] [PDF 2922KB] ( 37 )   
doi: 10.7503/cjcu20170660

Pyrene-doped silica fluorescent nanoparticles were prepared based on the micelle-template method. In the system, pluronic(F-127) was employed as template reagent, the mixture of pyrene trialkoxysilane derivatives(Pyrene-1) and tetraethoxysilane(TEOS) was used as silica precursors. The morphology, size distribution and photophysical properties of the obtained nanoparticles were characterized by means of transmission electron microscopy(TEM), dynamic light scattering(DLS), UV-Visible spectrophotometer and fluorescence spectrophotometer. The diameter of the nanoparticle measured by TEM was about 12 nm and the hydrodynamic diameter measured by DLS was about 33 nm. The prepared nanoparticles with uniform size showed good dispersibility and stability in water. The distance between dye molecules could be adjusted by changing the molar ratio between Pyrene-1 and TEOS. In addition, the dyes were fixed by the covalent bonds with Si-O-Si backbone in the nanoparticles, resulting in the increasing of fluorescence quantum yield(from 0.15 to 0.95 in CHCl3) and monomer fluorescence lifetime(from 17.9 ns to 191.8 ns in CHCl3). For the nanoparticles with high concentration of Pyrene-1, distinct Stokes shift up to 100 nm could be observed owing to the generation of excimer of Pyrene-1 molecules.

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YAO Wubing, YU Jiangjiang, HUANG Xiangyun, ZHANG Bin
A Highly Efficient Co-catalytic Beckmann Rearrangement Reaction
2018 Vol. 39 (5): 926-933 [Abstract] ( 36 ) [HTML 1KB] [PDF 2187KB] ( 62 )   
doi: 10.7503/cjcu20170560

Beckmann rearrangement reaction represents one of the most significant reactions in organic synthesis, and plays a very important role in the field of synthetic chemistry. The traditional Beckmann rearrangement reactions generally require high temperature and strong acids, and suffer from harsh conditions and serious environmental pollution. In this work, based on the efficient and commercial available cobalt tetrafluoroborate hexahydrate, the catalyst systems capable of highly efficient catalytic Beckmann rearrangement of ketoxime derivatives were developed, providing the amides with broad functional-group compatibility and high yields(up to 97%). With the active Co-catalyst in hands, the catalytic system also successfully conducted the transformantion on a 10 gram-grade scale, gaving the desirable product in 71% yield. Moreover, the Co-catalyzed Beckmann rearrangement reaction was extended to a one-pot protocol using ketone and hydroxylamine hydrochloride as reactive materials, offering the yield of products up to 94%. The novel system proceeded with additives and solvent free, and showed high atom-economy and good functional-group tolerance.

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GAO Yunxiao, HU Xiaolong, WANG Yuerong, JIANG Zhihong, ZHANG Hongyang, ZHANG Min, HU Ping
Primary Structural Analysis of Dendrobium officinale Polysaccharide
2018 Vol. 39 (5): 934-940 [Abstract] ( 31 ) [HTML 1KB] [PDF 1767KB] ( 45 )   
doi: 10.7503/cjcu20170464

A homogeneous polysaccharide(SDOP) was obtained from the fresh Dendrobium officinale. The relative molecular mass and composition of monosaccharide were then determined by gel permeation chromatography-laser scatter(GPC-LS) and high performance liquid chromatography with pre-column derivatization using 1-phenyl-3-methyl-5-pyrazolone(PMP) as derivatization agent. The detailed chemical structure of SDOP was elucidated by means of infrared spectroscopy, methylation analysis and nuclear magnetic resonance spectroscopy(NMR). The result shows that SDOP with an Mw of 1.66×106 consists dominantly of mannose and glucose in a molar ratio of 4.9:1.0. The results of NMR and methylation analysis suggest that SDOP is a 1,4-linked O-acetylated glucomannan, with a small amount of branch and end signal, while acetyl groups are mainly attached to the O-2 or O-3 positions on saccharide ring.

Physical Chemistry
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XIA Kun, WANG Yi, ZHOU Dan, HUANG Zhe, WU Zhonghan, XIA Qinghua
Rapid Synthesis of CoSAPO-5 Zeolite and Efficiently Catalytic Epoxidation of α-Pinene with Air
2018 Vol. 39 (5): 941-948 [Abstract] ( 28 ) [HTML 1KB] [PDF 4238KB] ( 40 )   
doi: 10.7503/cjcu20170756

A green catalytic reaction system with characteristic of high efficiency and energy saving for the synthesis of α-epoxy pinane by catalytic epoxidation of α-pinene with air was constructed. By using rotating hydrothermal route, the necessary time for crystal nucleation and growth of SAPO-5 was shortened distinctly, meanwhile the crystal size was decreased and the crystal size distribution became more uniform. Then, CoSAPO-5 catalyst was prepared by post treatment of SAPO-5 precursor. Under the investigation for various catalytic reaction conditions systematically, including solvent type, the amount of catalyst, reaction temperature, and reaction time, the optimal reaction system was established, under which the conversion of α-pinene can reach 96.5%, the yield of α-epoxy pinane can reach 89.0%, better than the best results reported. Moreover, CoSAPO-5 catalyst was also used in the catalytic epoxidation of other bulky alkene molecules. The recycling experiments indicate that CoSAPO-5 is an excellent heterogeneous recyclability catalyst.

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LU Lilin, SHU Hongfei, RUAN Zhuhua, NI Jiaqi, ZHANG Haijun
Preparation of Graphene-supported Pt-Pd Catalyst and Its Catalytic Activity and Mechanism for Hydrogen Generation Reaction
2018 Vol. 39 (5): 949-955 [Abstract] ( 33 ) [HTML 1KB] [PDF 3993KB] ( 34 )   
doi: 10.7503/cjcu20170720

The graphene-supported nano Pt-Pd bimetallic catalysts with various chemical compositions(Pt/Pd molar ratio:4:1, 1:1, 1:4) were prepared via simple ethanol reduction method by reflux of graphene oxide(GO) and metallic salts in ethanol/water solvent for 5.5 h at 88℃. For comparison, graphene-supported Pt, Pd monometallic catalysts were also synthesized under the same experimental conditions. The morphology of as-prepared catalysts was characterized by XRD and TEM, the results indicate that chemical composition of metallic catalysts shows distinct influence on the particle morphology and size, the Pt-Pd bimetallic catalyst particles disperse on the surface of graphene support most evenly with the average diameter of approximately 5.6 nm when the Pt/Pd molar ratio was set as 1:1. Their catalytic activities for hydrolysis reaction of alkaline potassium borohydride(pH=12.0) were investigated, the catalytic experiment results demonstrate that the catalytic activities significantly depend on chemical composition of metallic catalyst, among them the Pt-Pd bimetallic catalyst with the molar ratio of 1:1 displays higher activity than other Pt-Pd bimetallic catalysts(Pt/Pd molar ratios of 1:4 and 4:1) and Pt, Pd monometallic catalysts, the hydrogen generation efficiency of graphene-supported nano Pt-Pd(molar ratio 1:1) bimetallic catalysts is about 4380 molH2·molM-1·h-1, which is higher than graphene-supported Pt catalyst by 52% and approximately as four-fold as graphene-supported Pd catalyst. Investigation on the catalytic durability demonstrated that about 83% of the initial catalytic activity was retained even after three cycles. Catalytic reaction kinetics studies manifest the activation energy of borohydride hydrolysis reaction catalyzed by graphene supported Pt/Pd(molar ratio 1:1) bimetallic catalyst is about 20.90 kJ/mol, which is distinctly lower than those of the reaction catalyzed by Pt/C and Ru/C catalysts. DFT calculations based on M55 model revealed that the barrier height of rate-determining step catalyzed by Pt25Pd30 are distinctly lower than that catalyzed by Pd55 and Pt55, indicating the graphene supported Pt-Pd(Pt/Pd molar ratio 1:1) possess more excellent catalytic activity.

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ZHOU Liting, LEI Xiaoyang, WANG Weina, CHEN Dongping, LIU Fengyi, WANG Wenliang
Reaction Mechanism of Criegee Intermediate RCHOO(R=H, CH3) with Nitrogen Dioxide and Formation of HNO3 in the Atmosphere
2018 Vol. 39 (5): 956-963 [Abstract] ( 28 ) [HTML 1KB] [PDF 3515KB] ( 32 )   
doi: 10.7503/cjcu20170723

The mechanism of RCHOO(R=H, CH3)+NO2 reaction was studied at CCSD(T)/aug-cc-pVTZ//M06-2X/cc-pVDZ level. The influence of the methyl substitution on the reactivity was discussed. The results show that the reaction could take place through three channels addition-decomposition, oxidative H-transfer and hydrogen abstraction. Therein, the oxidative H-transfer reaction, which mainly produces the RCO+HNO3, is the favorable pathway. The apparent activation energy and release energy of the oxidative H-transfer reaction are 40.51 and 235.04 kJ/mol, respectively. Moreover, the methyl substituent will lead to the increase of the electropositivity on α-C and decrease of the electronegativity on terminal O, which is advantageous to proceed the addition-decomposition and oxidation-hydrogen transfer reaction. However, the reactivity of the addition-decomposition reaction reduced because of the prominent steric effect in syn-CH3CHOO.

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WANG Wenliang, SHI Yujie, WANG Shaohua, DANG Zepan, LI Xinping
Pyrolysis Behavior and Product Characteristics of Microwave co-Pyrolysis of Cellulose and Waste Tire
2018 Vol. 39 (5): 964-970 [Abstract] ( 43 ) [HTML 1KB] [PDF 2044KB] ( 33 )   
doi: 10.7503/cjcu20170717

The pyrolysis behavior and product characteristics of microwave co-pyrolysis of cellulose and waste tire were investigated by thermogravimetric analyzer(TG), the equipment of microwave co-pyrolysis, Fourier transform infrared analyzer(FTIR) and gas chromatography/mass spectrometry(GC-MS). The results show that the contents of residual carbons from different H/Ceff ratios(0.2, 0.4, 0.6) are lower than the theoretical values. Compared with the theoretical values at H/Ceff ratios(0.2, 0.4, 0.6), the yields of pyrolysis oil increase by 4.7%, 6.4% and 6.0%, respectively, indicating the occurrence of synergistic effect during the co-pyrolysis of cellulose and waste tire. The relative content of 79.5% for polycyclic aromatic hydrocarbons(PAHs) was observed in pyrolysis oil of waste tire. However, the PAHs were totally disappeared and converted into valuable oxygen containing compounds after the adding of cellulose, resulting in the quality improvement of pyrolysis oil.

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SHI Penghui, BIAN Liujiao
Mechanism Study on the Interaction Between Cefoxitin and Metal β-Lactamase BcⅡ Based on Spectroscopic Methods and Computional Simulations
2018 Vol. 39 (5): 971-976 [Abstract] ( 36 ) [HTML 1KB] [PDF 3887KB] ( 42 )   
doi: 10.7503/cjcu20170702

The interaction mechanism between cefoxitin(CFX) and metal β-lactamase BcⅡ was studied by synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy and molecular dynamics simulation. The results of fluorescence spectra show that CFX could induce the conformation changes of BcⅡ during their binding. The simulation results show that the conformational change of BcⅡ is an induction-fit process. Under the induction of CFX, the loops near the binding pocket of BcⅡ match perfectly with the substrate by changing their conformation, and eventually form a cave-like hydrophobic pocket to facilitate the binding process and catalyze hydrolysis. This study may provide some valuable reference and inspiration for the development of new antibiotics to resist the hydrolysis of metal β-lactamases.

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LIU Jingwei, YU Guangtao, SHEN Xiaopeng, HUANG Xuri, CHEN Wei
Theoretical Studies on the Structures, Electronic and Magnetic Properties of Fully and Partically Fluorizated Germanene Nanoribbons
2018 Vol. 39 (5): 977-982 [Abstract] ( 29 ) [HTML 1KB] [PDF 3790KB] ( 32 )   
doi: 10.7503/cjcu20170671

By means of the first principles computations, the geometries, stabilities, electronic and magnetic properties of fully and partially fluorizated Ge nanoribbons(GeNRs) with the zigzag or armchair edges were investigated. The computed results reveal that the chair-like configuration is the most energetically favorable one for fully fluorizated GeNRs(fF-GeNRs), regardless of the edge chirality. The full fluorization can widen the band gap of GeNR, and these fF-GeNRs systems can exhibit the uniform nonmagnetic semiconducting behavior, where the band gap decreases with the increase of ribbon width. The partially fluorizated zigzag GeNRs(pF-zGeNRs) are the antiferromagnetic semiconductors, while the partially fluorizated armchair GeNRs(pF-aGeNRs) are the nonmagnetic semiconductors. The band gap of pF-GeNR systems can increase with the increase of fluorization ratio, but the variation of band gap can exhibit three-family-behavior for pF-aGeNRs. Moreover, all the pF-GeNRs systems can exhibit the almost same electronic and magnetic properties as the remaining pristine GeNRs without fluorination, which can provide an effective approach to experimentally produce "narrow" GeNRs in a large scale. Clearly, fluorization is an effective strategy to modulate the electronic and magnetic properties of GeNRs, and particularly these fluorizated GeNRs systems can possess the high structural stabilities. These intriguing insights can be advantageous for promoting the practical applications of excellent Ge-based nanomaterials in the multifunctional nanodevice etc.

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LI Jianwei, LI Xiang, ZHANG Jie, LEI Zhigang
Mechanism of the Interaction Between Ionic Liquid[Bmim] [DBP] and Methanol for Seperation of Mixed C4/Methanol
2018 Vol. 39 (5): 983-989 [Abstract] ( 29 ) [HTML 1KB] [PDF 1643KB] ( 56 )   
doi: 10.7503/cjcu20170629

In this work, the extractive methanol removal from C4 hydrocarbon using ionic liquids(ILs) as extractants was studied. Firstly, the effect of structure of ionic liquid on extraction process was investigated. The results show that 1-butyl-3-methyl imidazole dibutyl phosphate([Bmim] [DBP]) performs the best extraction. According to the selected ionic liquid[Bmim] [DBP], quantum chemistry calculation method was used to explain the mechanism between ionic liquid[Bmim] [DBP] and methanol. The results show that stable hydrogen bonds not only exist between cation and anion in ionic liquid[Bmim] [DBP], but also exist between methanol and ionic liquid[Bmim] [DBP]. The hydrogen bonds strengthen the interaction among the molecules. The anion[DBP]- in[Bmim] [DBP] and -OH in methanol form a hydrogen bond of 0.1711 nm and the interaction energy is -62.08 kJ/mol. A series of experiments was carried out to determine the effect of ILs/C4 mass ratio, extraction time and recycle times on the performance of ionic liquid[Bmim] [DBP]. The results show that the extraction rate reaches 99.65% under the conditions of ILs/C4 mass ratio of 1:2, extraction time of 60 min, temperature of 25℃. Furthermore, the extration rate would not decrease after 5 recycles.

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WANG Gang, WANG Keliang, LU Chunjing, WANG Ying
Preparation and Foam Properties of Janus Particles
2018 Vol. 39 (5): 990-995 [Abstract] ( 27 ) [HTML 1KB] [PDF 2890KB] ( 30 )   
doi: 10.7503/cjcu20170656

The monodisperse silica nanoparticles were synthesized, and then amphiphilic Janus particles decorated with fluorinated chains were prepared by improving Pickering emulsions method. The self-assembly behavior at the air-water interface and foam properties of Janus particles were investigated. The size distribution of silica nanoparticles, surface morphology of wax colloidosomes and chemical composition, surface structure, interfacial activity, foam properties of Janus particles were characterized by particle size analyzer, scanning electron microscopy(SEM), Fourier transform infrared spectroscope(FTIR), fluorescence microscope, interfacial rheometer and foamscan. The results show that the surface of the prepared Janus particles is asymmetric. The test results of interfacial activity show that Janus particles have favorable interfacial activity at the gas/liquid interface, and the surface tension could be reduced to 38 mN/m. The test results of foam properties show that Janus particles effectively controll the coalescence and disproportionation, and the foam shows excellent stability.

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WANG Haidan, WANG Li, XU Mei, HUANG Lichen, SONG Xianliang
Synthesis of Bi2WO6/TiO2 Nanocomposites for the Photocatalytic Degradation of Ethylene
2018 Vol. 39 (5): 996-1002 [Abstract] ( 40 ) [HTML 1KB] [PDF 5086KB] ( 72 )   
doi: 10.7503/cjcu20170601

Bi2WO6/TiO2 nanocomposites were synthesized via solvent thermal method and characterized using X-ray powder diffractometer(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM) and Fourier transform infared spectrometer(FTIR). The results show that TiO2 nanoparticles can be attached to the surface of Bi2WO6 through the interaction of surface groups, thus leading to the hetergeneous structure. Moreover, the Bi2WO6/TiO2 nanocomposites have smaller grain size and higher specific surface area compared with single Bi2WO6 nanoparticles, which can be contributed to the reinforcement of photocatalytic activity under visible light irradiation. Experiments on degradation of ethylene indicated that Bi2WO6/TiO2 composites exhibited excellent photocatalytic performance under both simulated solar light irradiation and visible light irradiation. The rate constant K' of Bi2WO6/TiO2 could reach up to 9.312×10-4 min-1 under visible light irradiation, which increased by 89.34% and 884.25% compared with sole Bi2WO6 and TiO2, respectively.

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WANG Bin, WU Yingga, LIU Zhelin, WANG Xiaohong, AN Zhihua, ZENG Jun, YANG Peng, LIU Zongrui
Photocatalytic Activity of Keggin Type Polyoxometalates XW12O40n- (X=P5+, Si4+, B3+, Zn2+) Toward Degradation of Methyl Orange
2018 Vol. 39 (5): 1003-1008 [Abstract] ( 29 ) [HTML 1KB] [PDF 1983KB] ( 30 )   
doi: 10.7503/cjcu20170592

A series of Keggin type polyoxometalates with different central heteroatoms was prepared by the conventional aqueous synthesis method and characterized by powder X-Ray diffraction(PXRD), infrared spectroscopy(FTIR) and Raman spectroscopy(Raman). The optical and electrical activities of the polyoxometalates were studied by UV-Vis spectroscopy and cyclic voltammetry(CV). The influenece of central heteroatoms, catalyst dosage, substrate concentration and pH values on photocatalytic activity of the polyoxometalates toward methyl orange were investigated. The photodegradation activity of different Keggin type polyoxometalates toward methyl orange is in the order of ZnW12 > PW12 > SiW12 > BW12.

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ZHOU Yanli, CHEN Yingcai, WANG Chao
Simulation Study on the Migration of Polymer in Periodic Channels Under Weak Driving Force
2018 Vol. 39 (5): 1009-1017 [Abstract] ( 33 ) [HTML 1KB] [PDF 2518KB] ( 38 )   
doi: 10.7503/cjcu20170556

The migration of polymer in periodical channels under weak electrical driving force was studied by Langevin dynamics simulation. The channel was patterned alternately by part α and part β with the same length. The interaction between polymer and channel α was attractive, while that between polymer and channel β was purely repulsive. The results show that there are obvious trapped stages during the migration of polymer in periodical channels. The manner for polymer escaping from the trapped stage is dependent on the channel width. For narrow channel case, polymer keeps linear configuration and the movement seems like snake motion during the migration. The escape of polymer from the trapped stage needs the participation of the whole polymer, resulting that the mobility changes periodically with polymer length. At positions of the extreme point of the mobility, there are simple relations between the projected length of polymer and the period of the channel. For wide channel case, polymer keeps hair-pin or coil configuration and the movement seems like worm motion during the migration. Specially, when polymer is long, polymer can escape from the trapped stage by elongating the head part of the polymer, leading to the independent of the mobility on polymer length. The results may be helpful for polymer separation and controlled movement by using periodic channels.

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GUO Rui, LI Yunpeng, TU Ruixiang, SONG Bo, GUO Yu
Corrosion Inhibition of 3-Butyl-5, 5-dimethyhydantoin Imidazole Ammonium Salt on Q235 Steel in HCl Solution
2018 Vol. 39 (5): 1018-1025 [Abstract] ( 28 ) [HTML 1KB] [PDF 2886KB] ( 25 )   
doi: 10.7503/cjcu20170557

The corrosion inhibition performance and adsorption behavior of 3-butyl-5,5-dimethyhydantoin imidazole ammonium(BDMHI) for Q235 steel in HCl solution was investigated by mass loss method, polarization curve, electrochemical impedance spectroscopy(EIS), scanning electron microscopy(SEM), and contact angle measurements. The results show that inhibition efficiency increases with the increase of mass concentration of BDMHI and decreases with the increase of temperature; the highest inhibition efficiency is 91.62%; inhibition efficiency is above 80% at a BDMHI mass concentration of 1.0 g/L in the temperature range of 25-35℃. The adsorption properties of BDMHI were estimated using the standard adsorption Gibbs free energy change(ΔGads0) and enthalpy change (ΔHads0), respectively. The results reveal that the adsorption processes are exothermal and belong to a mix-type adsorption with physical adsorption and chemical adsorption, following Langmuir adsorption isotherm. The relationship between the molecular structure of BDMHI and the inhibition efficiency was investigated using quantum chemical calculations.

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CAO Hongyu, JIN Xiaojun, GUO Wei, YU Yaxian, SHI Longfei, TANG Qian, ZHENG Xuefang
Investigation on Binding Interactions Between Extracellular Amino-terminal Domain of GLP-1 Receptor Mutations and GLP-1 by Molecular Dynamics Simulations
2018 Vol. 39 (5): 1026-1033 [Abstract] ( 31 ) [HTML 1KB] [PDF 3985KB] ( 25 )   
doi: 10.7503/cjcu20170547

Binding interactions between the extracellular amino-terminal domain(ECD) of glucagon-like peptide-1(GLP-1) receptor and GLP-1 were studied by molecular dynamics simulations. As shown in calculation results, the binding ligand led to conformational changes of the receptor. Pro90 and Trp91 in Loop2 and Glu128 in the C-terminus moved towards the ligand upon ligand binding. The receptor ECD was mutated in some conserved residues(P73A, V81L, Y88A, P90A and W91A), whose structures and flexibilities have changed violently. Mutations of Trp91 and Tyr88 led to complete loss of binding affinity of the ligand and the effects of those mutations were discussed elaborately. Given all the results, there was no big difference between the interactions related to the receptor ECDP73A and the wild type, which suggested that Pro73 was not vital for ligand binding, while mutation of V88L might make a complete affinity loss of GLP-1.

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YAN Lingling, LIU Chunguang, JIANG Mengxu
Theoretical Study on Cation Detection Ability of Pyridine-substituted Lindqvist-type Ployoxometalates Based on Linear and Nonlinear Optical Properties
2018 Vol. 39 (5): 1034-1040 [Abstract] ( 43 ) [HTML 1KB] [PDF 1223KB] ( 31 )   
doi: 10.7503/cjcu20170549

Linear(wavelength of maximum absorption, λmax) and nonlinear optical(hyper-Rayleigh scattering first hyperpolarizability, βHRS) properties of a series of pyridine-substituted Lindqvist polyoxometalates(POMs) were studied via density functional theory(DFT)-B3LYP method. The potential abilities for metal cation sensor of these Lindqvist POMs were probed. The calculated adsorption energy of metal cation on these Lindqvist POM ligand indicates that the interaction strength of them decreases in the order of Ni2+ > Cu2+ > Co2+ > Fe2+ > Zn2+ > Mg2+ > Ca2+. The calculated results indicate that the linear and nonlinear optical properties can be effectively tuned by the introduction of electron donor and acceptor. Meanwhile, pyridine-substituted Lindqvist POM ligands display various detection functional for the seven metal cations(Cu2+, Zn2+, Ca2+, Mg2+, Ni2+, Co2+, Fe2+).

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CAI Zhuang, WANG Guiling, SONG Congying, YANG Xueying, HU Rong, YE Ke, ZHU Kai, CHENG Kui, YAN Jun, CAO Dianxue
Preparation of a Binder Free Electrode of NiAg Supported on Graphite Modified A4 Paper and Its Electrochemical Performance for H2O2 Reduction
2018 Vol. 39 (5): 1041-1047 [Abstract] ( 40 ) [HTML 1KB] [PDF 8183KB] ( 33 )   
doi: 10.7503/cjcu20170529

An original electrode of NiAg supported on graphite modified A4 paper(NiAg@C/A) was prepared through electrodeposition and galvanic displacement without binder for H2O2 electroreduction. The morphology and phase composition of the as-prepared electrode were investigated by X-ray diffractometer(XRD), scanning electron microscope(SEM) and transmission electron microscope(TEM). And cyclic voltammetry and chronoamperometry were conducted to study the electrochemical performance of the NiAg@C/A electrode. The results reveal that the reduction current density of H2O2 on the NiAg@C/A electrode reaches 600 mA/cm in a solution of 0.6 mol/L H2O2 and 1 mol/L NaOH at -0.8 V. The NiAg@C/A electrode exhibits good stability toward the H2O2 reduction and is a good alternative for H2O2 electroreduction in the future.

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YU Kaile, PAN Xinyu, ZHANG Zhengfang, WANG Qiang
Determination of Solubility Parameters of Imidazolyl Acetate Ionic Liquid by Inverse Gas Chromatography and Hansen Solubility Parameters
2018 Vol. 39 (5): 1048-1054 [Abstract] ( 30 ) [HTML 1KB] [PDF 1520KB] ( 27 )   
doi: 10.7503/cjcu20170479

The solubility parameters of four imidazolyl acetate ionic liquids were determined by inverse gas chromatography in the range of 353.15-393.15 K. The results show that the solubility parameter values of the four ionic liquids decrease linearly with the increase of temperature in the experimental temperature range. The solubility parameters of the four ionic liquids are 26.14, 24.38, 23.60 and 23.04 MPa1/2 at 333.15 K by extrapolation method. The solubility parameters of the ionic liquid were also simulated by Hansen solubility parameter software at 333.15 K. The simulation results are 26.52, 23.99, 23.45 and 22.00 MPa1/2, respectively. The results obtained by the two methods are consistent with each other in the error rang of ±1.05 MPa1/2, indicating that the two methods are applicable to the determination of the solubility parameters of imidazolyl acetatp/>).

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YANG Dongsheng, WANG Lei, CHEN Ling, ZHOU Jinya, FENG Wei, ZHANG Jianhui
Preparation and Properties of N-Doped Carbon Microtubes as the Electrode Material in Electrochemical Capacitor
2018 Vol. 39 (5): 1055-1062 [Abstract] ( 47 ) [HTML 1KB] [PDF 4635KB] ( 44 )   
doi: 10.7503/cjcu20170474

A series of N-doped carbon microtubes was prepared by using Reed catkins as the precursor and with both direct carbonization and chemical activation methods at different temperatures. The chemical activation method is more efficient, simpler and cost less compared to the traditional preparation method of N-doped carbon microtubes. The chemical activation material JJCZH-750(JJ stands for Reed catkins, Z stands for Zinc chloride, C stands for carbonization and 750 the optimized temperature) was optimized. The carbon microtubes were characterized by X-ray diffraction, infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis(TGA), X-ray photoelectron spectroscopy, N2 adsorption-desorption analysis, and electrochemical measurements. The results show that carbon accounts for 94.36%(mass fraction) and nitrogen accounts for 1.24%(mass fraction) of the sample, which shows a tendency to exist as graphite. TGA analysis of the samples indicates a high thermal stability with a mass loss lower than 5% below 400℃. N2 sorption isotherms show that the samples is predominantly microporous(peak 1.2 nm) and occasionally mesoporous. Electrochemical measurements suggest that Reed catkins-based JJCZH-750 carbon microtubes have a specific capacitance up to 170 F/g, which remains at 153 F/g after 5000 cycles in a voltammetry test, showing a potential as electrode material in electrochemical capacitors.

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HUANG Jipei, LI Yi, YANG Shenhui, ZHOU Yazhou, CHENG Xiaonong, ZHU Jia, YANG Juan
Synthesis of Three-dimensional Pt-Ag Aerogels and Their Electrocatalytic Performance Toward Oxygen Reduction Reaction
2018 Vol. 39 (5): 1063-1071 [Abstract] ( 38 ) [HTML 1KB] [PDF 7845KB] ( 42 )   
doi: 10.7503/cjcu20170444

The etched-platinum-silver aerogel(e-Pt-Ag gel) electrocatalysts with dendritic morphology were synthesized by chemical reduction and hydrothermal method, in which silver nanoparticles were removed by acid-and alkali-etching. X-ray diffraction(XRD), scanning electronic microscopy(SEM) and transmission electron microscopy(TEM) were employed to characterize the composition, structure and morphology of e-Pt-Ag gel. The activity and stability of the catalysts for oxygen reduction reaction(ORR) were studied by cyclic voltammetry(CV) and linear sweeping voltammetry(LSV) methods. The results show that the e-Pt-Ag gel exhibits excellent ORR performance and favorable durability. In detail, the mass and specific activities of e-Pt-Ag gel at 0.9 V are 166.3 mA/mgPt and 0.295 mA/cm2, respectively, which are 2.0 and 1.8 times that of the commercial Pt/C catalyst[84.9 mA/mgPt and 0.163 mA/cm2]. Furthermore, the mass and space activities of the e-Pt-Ag gel only decay 6.1% and 9.1%, respectively, after 5000 electrochemical cycles, showing higher durability of the e-Pt-Ag gel compared with Pt/C(35%, 52.1%).

Polymer Chemistry
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YAN Tingting, XING Guolong, BEN Teng, QIU Shilun
Influence of Building Blocks on Gas Adsorption Performance of Porous Aromatic Frameworks
2018 Vol. 39 (5): 1072-1077 [Abstract] ( 34 ) [HTML 1KB] [PDF 2378KB] ( 39 )   
doi: 10.7503/cjcu20170781

We synthesized and characterized two kinds of analogical porous aromatic frameworks by selecting two different building blocks, 1,3,5-tribromobenzene(TBB) and 3,3',5,5'-terabromo-1,1'-biphenyl(TBBP), catalyzed by Yamamoto type Ullman coupling reaction. The results proved that the properties of the porous aromatic frameworks are similar. Both of them show higher BET surface areas, uniform pore size distributions, excellent stability, and potential applications in gas adsorption and storage. Meanwhile, the differences in specific surface area and gas adsorption between the porous aromatic frameworks can be attributed to the differences between the building blocks.

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LONG Shijun, CHEN Mingmin, ZHAO Youjiao, WANG Xiaotao, LI Xuefeng, LIAO Yonggui
Regulation of Gemini Surfactant on Photochromic Behavior of PVA Dispersed Spiropyran Organogel Thin Film
2018 Vol. 39 (5): 1078-1083 [Abstract] ( 27 ) [HTML 1KB] [PDF 1614KB] ( 45 )   
doi: 10.7503/cjcu20170754

Polyvinyl alcohol(PVA) dispersed spiropyran(SP) organogel thin film(PDPG-SP) was prepared by a facile co-solvent-evaporation strategy. 1,6-Didodecyl(dimethyl) azanium bromide hexamethylene used to regulate interface interaction between PVA/organogel was used as one sort of Gemini surfactant. The photochromic and fading behavior, microstructure morphology, mechanical properties and light fatigue resistance of PDPG-SP were investigated. The results show that the thermal decay behavior for PDPG-SP film is similar to that of SP/PPG solution. Interestingly, PDPG-SP also has excellent mechanical property with elastic modulus and tensile strength as high as ca. 547 and ca. 23.5 MPa respectively. After 10 repeated coloration-discoloration cycles, the intensity at the maximum absorption wavelength decreases by about 35%, which was decreased dramatically comparing with that using PVA1 as a surfactant(ca. 53%). Based on the separation force by head-end gathering process of Gemini, the anchor effect of PVA/organogel interface on SP is suppressed. Meanwhile, more SP molecules were protected within micro-solvent environment, which was homogeneously dispersed in PVA matrix. The anchor effect increases the number of SP molecules that could conduct reversible free isomerization, accelerating the fading rate and improving the fatigue resistance of the PDPG-SP thin film concurrently.

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YANG Zewen, ZHANG Yanyan, FU Feiya, LIU Xiangdong
Preparation and Properties of a Bio-based Unsaturated Polyester Resin Glue and Its Cotton Fabric-reinforced Composite
2018 Vol. 39 (5): 1084-1090 [Abstract] ( 39 ) [HTML 1KB] [PDF 1906KB] ( 35 )   
doi: 10.7503/cjcu20160675

A novel blending solvent, the mixture of acrylated epoxidized soybean oil(AESO) and glycidyl methacrylate(GMA), was proposed to prepare bio-based unsaturated polyester systems. The bio-based unsaturated polyester(UPOEM) was synthesized by ethylene glycol, oxalic acid and maleic anhydride via a melt polycondensation. By dilution using the blending solvent of AESO/GMA, the resulting unsaturated polyester resin glues have low viscosity, high bio-based content, good storage stability, and improved wettability with reinforcing fibers. Experimental data show that GMA can effectively reduce the viscosity of the AESO/UPOEM systems. When GMA, AESO and UPOEM are blended in a mass ratio of 100:100:300, the viscosity is decreased to 780 mPa·s, only 5.4% of the original. The GMA/AESO/UPOEM mixture keeps yellow and transparent, and the viscosity is constant at room temperature for more than 30 d. Furthermore, green composites were prepared by compositing the unsaturated polyester systems with cotton fabrics via a free radical polymerization performed at 100℃ for 2 h and 150℃ for 3 h, under a pressure of 15 MPa in a hot pressing machine, and using a mixture of tert-butyl peroxybenzoate and isophorondiamine as initiator. The tensile and thermo-mechanical properties of the resulting green composites were examined by universal testing machine, dynamic mechanical analysis(DMA) and thermogravimetric analysis(TGA), respectively. The results show that the composites have good tensile strength close to 30 MPa, and their glass transition temperature(Tg) and thermal decomposition temperature(Td,5%) are greater than 90℃ and 248℃, respectively. These results suggest that the bio-based unsaturated polyester systems have a great potential for various applications.

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REN Huicheng, WU Yingfei, LIU Dandan, NIE Huarong, HE Aihua
Crystallization, Nucleation and Kinetics of TPI in SSBR/TPI Blends
2018 Vol. 39 (5): 1091-1097 [Abstract] ( 29 ) [HTML 1KB] [PDF 3317KB] ( 26 )   
doi: 10.7503/cjcu20170664

Crystallization behavior including polymorphic behavior, nucleation density, crystal growth rate, kinetics of isothermal and non-isothermal crystallization in the immiscible solution polymerized styrene-butadiene rubber(SSBR)/trans-1,4-polyisoprene(TPI) blends were investigated by polarized optical microscopy(POM), wide angel X-ray diffraction(WAXD) and differential scanning calorimeter(DSC). The results show that less than 40%(mass fraction) of SSBR admixing with TPI brings about the suppressed nucleation and crystal growth rate of TPI. The overall crystallinity declines with the addition and increase of amorphous SSBR content, the normalized crystallinity of TPI, however, increases due to the decreased crystallization rate, resulted from the dilution of SSBR components, in turns the reduced equilibrium melting points and the lower undercooling. Additionally, the amorphous component SSBR depresses the formation of α-TPI crystal while enables the formation of β-TPI crystal. Both the reduced crystallization rate of TPI during the isothermal crystallization and the lower crystallization temperature of TPI during non-isothermal crystallization were observed with the increase of SSBR content. All these results are in line with the crystallization behavior of the miscible amorphous/crystalline polymer blends because of the neglectable phase separation arising from the high viscosity of both rubber components leading to the slow dynamic of molecules. However, as the content of SSBR reached a high level, the nucleation density of the system increased with SSBR content increasing due to the phase separation exerting its influence on TPI crystallization.

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WANG Zhengzhou, YANG Ting
Preparation and Properties of Expanded Vermiculite Coated Expanded Polystyrene/Cement Composite Foams
2018 Vol. 39 (5): 1098-1104 [Abstract] ( 33 ) [HTML 1KB] [PDF 6395KB] ( 29 )   
doi: 10.7503/cjcu20170654

Expanded polystyrene(EPS) particles were encapsulated with epoxy resin and then with expanded vermiculite(EV) to obtain surface inorganically modified EPS(CEPS) particles. The CEPS particles were mixed with cement, water and other additives, and cured at room temperature to prepare CEPS/cement composite foams. The effects of the coating amount and CEPS content on mechanical properties and insulation performance of the composite foams were investigated, and the fire resistance of composite foam materials was also studied by cone calorimetry and butane flame spray combustion. The results show that the flexural strength, compressive strength, dry density and thermal conductivity of the composite foams increase with the increase of the coating amount. The composite foam with 1000 mL of CEPS has lower dry density and thermal conductivity, which are 269.3 kg/m3 and 0.0544 W/(m·K), respectively, and the flexural strength and compressive strength of the composite foam are relatively high. The cone calorimeter test results show that the peak heat release rate, total heat release and total smoke release of the composite foams are decreased gradually with the increase of the coating amount, and the ignition time of the foams is prolonged. The results of butane flame spray combustion indicate that the fractured surface of the composite foams can be maintained intact after burning, and only the EPS beads exposed on the fractured surface of the composite foams are burned out.

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LIU Zhihui, QIU Tianyuan, DU Liuyi, YANG Junxing, LIU Kang, WANG Bowei
Preparation and Characterization of Chitosan Alginate Plastic Scaffolds
2018 Vol. 39 (5): 1105-1112 [Abstract] ( 32 ) [HTML 1KB] [PDF 4652KB] ( 33 )   
doi: 10.7503/cjcu20170565

Based on anion and cation electrostatic load principle, using sodium alginate and chitosan as raw materials, sustained-release microspheres were obtained by the drip method and layer-by-layer self-assembly. The microspheres were then put into a certain percentage of sodium alginate-chitosan solution, and a new kind of scaffold with microspheres embedded in the spongy structure called sustained-release microsphere-type scaffolds was obtained. The influences of the component ratio of the sustained-release microspheres on the porosity, contraction, hydrophilicity and degradation properties of the sustained-release microsphere-type scaffolds were investigated. The pore size was between 140 and 200 μm analyzed by scanning electron microscopy(SEM). There was no difference in the cytotoxicity text of the scaffold's leachate between the experimental group and the control group. When the component ratio of microspheres was 10%, the scaffolds had the highest porosity ratio(68.2%-70.8%), the lowest contraction percentage(4.4%-5.2%) and the best hydrophilicity. The less microspheres the scaffolds had, the faster the degradation rate was. For preventing the degradation rate too fast and carrying more medicines, the scaffolds, whose component ratio of microspheres was 20%, are much better. The microsphere-type scaffold material has good plasticity before freeze-drying. The microsphere-type scaffolds provided an example of the combination with sustained-release systems and existing porous scaffold materials.

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