POLYMER BULLETIN
·
2016
·Vol. 74
·期 2
·359-367
·
IF 1.371
Wei Kun,Ma Biao,Wang Hainian,Liu Yu,Luo Yu
A series of novel epoxy polymer shell microcapsules with n -tetradecane and dimethylbenzene as binary core materials are successfully synthesized via interfacial polymerization. Dimethylbenzene is used as the solvent for epoxy and n -tetradecane. The chemical structure, surface morphology, and thermal properties of the microencapsulated phase-change materials (micro-PCMs) are characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscope. Results show that the micro-PCMs have relatively spherical profiles and smooth surfaces with diameters ranging from 10 to 70 μm. The epoxy shell successfully encapsulates the binary core. Phase-change enthalpy and binary core content in the micro-PCMs increase with the increasing mass ratio of the binary core to the epoxy resin. The micro-PCMs degrade in two steps, and the resulting microcapsules exhibit good thermal stabilities. The degradation temperature decreases, as the core-to-shell mass ratio increases.
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JOURNAL OF MATERIALS SCIENCE
·
2016
·Vol. 51
·期 18
·8502-8515
·
IF 2.302
Ran Junhui,Wang Haiying,Cheng Xinjian
Fluorescent chemosensors based on silica nanoparticles and silicate glass slides were well designed and prepared. The as-prepared fluorescent silica particles and glass slides exhibited highly selective sensing and absorbing abilities to Pd 2+ ions in aqueous phase. SiO 2 nanoparticles were first synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS), and then –NH 2 groups were introduced to silica by treating with 3-aminopropyltriethoxysilane (APTES). Subsequently, 4-amino-1,8-naphthalic anhydride (ANA) was incorporated with the reaction of –NH 2 groups. Finally, salicylaldehyde (SA) was introduced by the reaction between amino groups in ANA and the –CHO groups in SA. Thus, the fluorescent silica nanoparticles were obtained. This method was expanded to prepare fluorescent silicate glass slides. Upon the addition of Pd 2+ ions, the fluorescence quenched immediately. These chemosensors were selectively sensitive to Pd 2+ ions as low as 10 μM. The absorption efficiency of fluorescent nanoparticles and glass slides for Pd 2+ reached to 38.38 and 27.50 %, respectively. And the chemosensors also could be easily recycled and reused for at least five times. Fluorescent silica nanoparticles with only ANA or SA (not ANA and SA together) also exhibited the sensing ability to Pd 2+ ions; however, it showed the shortage of Pd 2+ ions selectivity. It suggested that it is necessary to introduce both ANA and SA for the high sensitivity and selectivity to Pd 2+ ions.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2016
·Vol. 80
·期 2
·326-332
·
IF 1.473
Ma Wenle,Feng Yongmei,Wang Li,Xue Junying,Cui Hongtao
Abstract Mn 3 O 4 nanoparticles were prepared at 60 °C in ethanol solution by a facile precipitation method. It was found that the particle size of the as-prepared Mn 3 O 4 depended on the alkalinity of precipitants. Nanoparticles with average size of 6 nm were obtained by using morpholine as precipitant which had low alkalinity, while 10 nm particles were produced by using NaOH as precipitant. The former particles presented higher degree electrochemical double-layer capacitor-like behavior and higher electrochemical performance than the latter. This could be attributed to the effective faradaic reactions of particles, which originated from the low equivalent series resistance resulting from their smaller particle size. Graphical Abstract Mn 3 O 4 nanoparticles were prepared in ethanol by a facile precipitation method using precipitants with different alkalinity. It was found that smaller particles (a) were generated by using precipitant with low alkalinity as compared with the one with higher alkalinity (b). As a result, the Mn 3 O 4 nanoparticles presented a high-degree electrochemical double-layer capacitor-like behavior due to their low equivalent series resistance.
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Journal of the Iranian Chemical Society
·
2016
·Vol. 13
·期 10
·1759-1765
·
IF 1.3
Wang Tingting,Zhang Dan,Zhang Ziliang,Han Juan,Wang Yun,Tang Xu
As a novel and green pretreatment technique to trace samples, polyoxyethylene cetyl ether (POELE20)–(NH 4 ) 2 SO 4 aqueous two-phase extraction system was coupled with high-performance liquid chromatography to analyse synchronously chloramphenicol (CAP), thiamphenicol (TAP) and florfenicol (FF) in chicken and pork samples. It was found that the extraction efficiency ( E %) and enrichment factor ( F ) of the three antibiotics were influenced by the types of salts, the concentration of salt, the concentration of POELE20, system temperature and pH. The final optimal condition was as following: the phase-forming salt is (NH 4 ) 2 SO 4 , the concentration of (NH 4 ) 2 SO 4 is 0.141 g mL −1 , the concentration of POELE20 is 0.03 g mL −1 , the temperature is 298.15 K, and the system pH is 4.5. This POELE20–(NH 4 ) 2 SO 4 ATPS was applied to separate and enrich three antibiotics in real sample under the optimal conditions, and it was found that the recovery was 97.20–102.00 % with a RSD of 0.61–4.85 %. The limit of detection for CAP, TAP and FF were 0.10, 0.50 and 0.50 μg kg −1 , and the limit of quantitation for CAP, TAP and FF was 0.15, 1.50 and 1.50 μg kg −1 . Seven times the experiments were used to verify the repeatability and veracity of this method, and the RSD for the intra-day and inter-day were 1.13–3.22 and 1.74–4.72 %.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2016
·Vol. 408
·期 25
·7095-7103
·
IF 3.125
Yu Linpo,Liu Yang,Zhou Ming
Ruthenium(II) complexes with carboxylic acid as a bioconjugatable group, i.e., [Ru(bathophenanthroline disulfonate)(2,2′-bipyridine)(4-methyl-4′-(3-carboxypropyl)-2,2′-bipyridine)] 0 , (C 49 H 38 N 6 O 8 S 2 Ru), and [Ru(bathophenanthroline disulfonate) 2 (4-methyl-4′-(3-carboxypropyl)-2,2′-bipyridine)] 2− · 2Na + , (C 63 H 44 N 6 O 14 S 4 RuNa 2 ) were characterized spectroscopically and electrochemically. As potential labels for electrochemiluminescence (ECL) immunoassays, the ECL intensities of the free labels in homogenous aqueous buffer solutions were compared under a condition that is similar to the one employed by a commercial clinical immunoassay system. The two labels were found to be more emissive and, thus, can be detected at 10 - 12 pM compared with 5× 10 −12 pM of the label currently used in the commercial ECL system. Furthermore, the improved ECL emission of the free labels in homogenous solutions was proven to be translated into more intense ECL signal in heterogeneous sandwich immunoassay and, thus, leading to a lower limit of detection in immunoassay. The data obtained from these ECL labels shed light on the further development of ECL-based clinical immunoassay technology.
Electrochemiluminescence immunoassays were carried out with three different ruthenium(II) complex labels. It was proved that the higher signal intensities found with the novel labels in homogeneous solutions were maintained in heterogeneous sandwich format.
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PubMed
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JOURNAL OF SURFACTANTS AND DETERGENTS
·
2017
·Vol. 20
·期 5
·1121-1127
·
IF 1.45
Chen Xuewei,Xin Yujuan,Yu Fangcai,Lan Zhili
A series of carboxylic ester-containing imidazolium-based zwitterionic surfactants, namely, monoalkyl 2-(3-methylimidazolium-1-yl) succinate inner salts (C n MimSU, n = 8, 10, 12 and 14), have been synthesized. Their structures were confirmed by 1 H NMR, 13 C NMR and FTIR. The typical physicochemical properties parameters such as isoelectric point, critical micelle concentration (CMC), surface tension at CMC ( γ
CMC ), surface pressure at CMC (Π CMC ), adsorption efficiency (p C
20 ), the maximum surface excess ( Γ
m ), the minimum molecular cross-sectional area ( A
min ) and the value of CMC/ C
20 were determined. The effect of the long-chain length on the important physicochemical properties of C n MimSU was studied. It is found that the surface activity of C n MimSU is enhanced with the long-chain length increases.
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Reaction Kinetics Mechanisms and Catalysis
·
2017
·Vol. 122
·期 1
·525-538
·
IF 1.264
Li Xin,Meng Fanhui,Cheng Yang,Gao Yuan,Li Zhong
Mesoporous silica (SiO 2 ) supported highly dispersed Ni catalysts with ZrO 2 and surfactant β-cyclodextrin (CD) were prepared by the impregnation method, and their catalytic performance for three-phase methanation of CO were evaluated. It is shown that ZrO 2 promotes the dispersion of Ni species on mesoporous SiO 2 , leading to the increase in Ni dispersion and methanation activity. For the ZrO 2 content, the optimum is 5 wt%. Moreover, when adding CD in the preparation of Ni5Zr/SiO 2 catalyst, CD was found effectively enhanced the dispersion of Ni species and interaction between Ni species and support, leading to a smaller size of NiO particles and more exposed active surfaces, which promotes the CO adsorption capacity. As the molar ratio of CD/Ni rises, the crystallite size of metallic Ni decreased. Ni5Zr/SiO 2 (1:5) catalyst prepared with 5 wt% ZrO 2 and 1:5 molar ratio of CD/Ni shows the optimal catalytic activity for the three-phase CO methanation reaction. This is because of the highest dispersion of metallic Ni and smallest size of NiO particles.
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BIOTECHNOLOGY AND BIOPROCESS ENGINEERING
·
2017
·Vol. 22
·期 1
·76-82
·
IF 1.16
Gu Jia-Li,Tong Hong-Fei,Sun Lai-Yu
Macroporous magnetic agarose particles (MMAPs) were prepared with calcium carbonate as the porogent by the water-in-oil suspension thermal regeneration method. MMAPs with good sphericity and appropriate particle size were obtained. The physical properties of the beads were determined and it was found that the water content (92.1%), porosity (94.4%) and mean pore diameter (120.1 nm) of the MMAPs were higher than those for the normal magnetic particles, indicating successful generation of macropores after calcium carbonate addition. Compared with normal magnetic particles, the mass transfer of biomolecules in MMAPs was remarkably enhanced. Finally, MMAPs were modified with 5-amino-benzimidazol (ABI) ligand and the adsorption capacity of IgG reached 153 mg/mL, higher than that of the normal magnetic particles (126 mg/mL). Moreover, adsorption behavior of MMAPs to IgG was little changed after twenty-five recycled use. Hence, MMAPs prepared herein showed great potential for bioseparation.
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JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
·
2016
·Vol. 25
·期 11
·5014-5019
·
IF 1.094
Zeng Xiaojun,Liu Weiliang
Boron carbide (B 4 C)-silicon (Si) composites have been prepared by aqueous tape casting, laminating, and spark plasma sintering (SPS). The influences of silicon (Si) content on the phases, microstructure, sintering properties, and mechanical properties of the obtained B 4 C-Si composites are studied. The results indicate that the addition of Si powder can act as a sintering aid and contribute to the sintering densification. The addition of Si powder can also act as a second phase and contribute to the toughening for composites. The relative density of B 4 C-Si composites samples with adding 10 wt.% Si powder prepared by SPS at 1600 °C and 50 MPa for 8 min is up to 98.3%. The bending strength, fracture toughness, and Vickers hardness of the sintered samples are 518.5 MPa, 5.87 MPa m 1/2 , and 38.9 GPa, respectively. The testing temperature-dependent high-temperature bending strength and fracture toughness can reach a maximum value at 1350 °C. The B 4 C-Si composites prepared at 1600, 1650, and 1700 °C have good high-temperature mechanical properties. This paper provides a facile low-temperature sintering route for B 4 C ceramics with improved properties.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2016
·Vol. 408
·期 27
·7595-7605
·
IF 3.125
Bo Chunmiao,Wang Chaozhan,Wei Yinmao
Immobilized metal affinity chromatography (IMAC) has been widely used for the specific separation of biopolymers. However, leakage of metal ions from IMAC adsorbents is of concern in IMAC. In this study, we designed a novel tridenate bis(5-methyltetrazolium)amine (BMTA) to reduce the leakage of metal ions by improving the affinity to immobilized metal ions. The ligand was bonded onto silica via three-step reaction to prepare a high-performance IMAC stationary phase. The chromatographic behaviors of ribonuclease A, cytochrome c , and lysozyme on the Cu(II)-, Ni(II)-, and Zn(II)-chelated stationary phase were investigated with respect to pH effect and elution with an imidazole gradient. The retention times of these three proteins increased by increasing the pH of the mobile phase but decreased by increasing the concentration of the competitive displacer. The retaining strength of the three proteins on the chelated stationary phase were in the order Cu(II) > Ni(II) > Zn(II). The behavior of these three proteins was consistent with the properties of a typical IMAC. The BMTA ligand exhibited a much stronger affinity for Cu(II) and Ni(II) than iminodiacetic acid (IDA), which is often regarded as a standard tridentate IMAC ligand. Quantum mechanical calculations at the B3LYP/6-31G level were used to image the coordination mode of the protein-metal ions-BMTA complex. In addition, a fused histidine-tagged cecropin b-human epidermal growth factor (CB-EGF) from Escherichia coli crude extract was purified by the Ni(II)-chelated stationary phase, and the purity of the CB-EGF was determined to be at least 90 %. These results suggest that the BMTA ligand may have potential applications in the preparation of therapeutics.
A novel ligand of tridenate bis(5-methyltetrazolium)amine (BMTA) was designed to reduce the leakage of metal ions from the column in immobolized metal affinity chromatography (IMAC).
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 28
·期 1
·949-957
·
IF 1.798
Qiu Qingchao,Yang Weihua,Zhan Yangfan,Wang Hao
The development of non-noble metal catalysts is of great interest due to their significant potential application in both fuel cell system and metal-air batteries, particularly when considering long term commercial deployment. Fe/N/C is a promising non-Pt electrocatalyst for the oxygen reduction reaction (ORR), but its catalytic activity is considerably inferior to that of Pt in acidic medium. In this paper, an improved Fe/N/S/C catalyst (denoted as Fe–N–S/C) is presented. Nitrogen-sulfur-iron-doped porous carbon material is synthesized by the pyrolysis of dicyandiamide, a kind of abundant and inexpensive compound, with thiourea as additional sulfur source in argon atmosphere. The Fe–N–S/C shows excellent performance for the ORR with the onset and half-wave potential at 0.89 and 0.78 V (vs.RHE) in 0.1 M H 2 SO 4 solution, respectively, which are significantly higher compared to those of the catalysts derived from only dicyandiamide (0.85 and 0.75 V). Our results indicate that as compared to the commercial 20 % Pt/C catalyst, the synthesized catalyst exhibits not only higher current density and long-term durability but also higher tolerance to methanol poisoning. More importantly, the synthetic method is simple and inexpensive.
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JOURNAL OF POROUS MATERIALS
·
2017
·Vol. 25
·期 4
·1027-1034
·
IF 1.624
Chen Yongquan,Yang Haitao,Nie Jun,Zhu Xiaoqun
Highly flexible silica aerogels were fabricated by using 2-(3-(triethoxysilyl)propylcarbamoyloxy) ethyl acrylate (TESEA), methyltriethoxysilane (MTES), and polydimethylsiloxane (PDMS) as co-precursors through photopolymerization and sol–gel process, then followed by ambient pressure drying. Attributing to photolysis of the photoacids generators, the radical and Brönsted acid (HSbF 6 ) were generated simultaneously under irradiation. The radical initiated the photopolymerization of acrylate which induced the gelation and fixed the shape of the gel quickly, the acid allowed the sol–gel process occurring gradually. Due to the enhancement of the polymer, the strength of aerogels was improved. The aerogels had low density (~ 0.098 g/cm 3 ), high porosity (~ 94.8%), high flexibility and high elastic recovery. Moreover, the silica aerogels have hydrophobic and oleophilic properties, which endows them with an ability of oil water separation.
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