JOURNAL OF AOAC INTERNATIONAL
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2019
·Vol. 97
·期 1
·121-127
·
IF 1.201
Wang Lili,Deng Jian,Ji Xuezhen,Liu Wanbin,Liang Jun,Yan Xiaona,Chen Dan,Xie Jie
A novel derivative β-cyclodextrin (β-CD) bonded silica gel (β-CD/SiO2) was prepared via carbodiimide activation and used as a chiral stationary phase (CSP). The β-CD/SiO2 CSP was characterizedby X-ray photoelectron spectroscopy and FTIR spectroscopy to prove the successful immobilization of β-CD onto the surface of the silica gel.The thermal behavior of the CSP was studied by differential scanning calorimetry and then used forthe chiral separation of racemic naproxen using HPLC. Several factors affecting the separation efficiency of naproxen enantiomers were investigatedsystematically. The following parameters were selected: methanol–0.01 M phosphate buffer solution (85 + 15, v/v, pH 3.5) was the mobile phase, the flow rate was 1.0 mL/min, and the column temperature was 35°C. Under optimal conditions, the racemic naproxen was efficiently separated with a resolution factor (RS) of 1.70 and a separation factor (α) of 1.25. This method was successfully used for the enantiomeric separation and purity assessment of naproxen in commercial naproxen sustained release tablets.
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Journal of Materials Chemistry A
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2019
·Vol. 7
·期 12
·6832-6839
·
IF 10.733
Yinghua Zhu,Jiang Cao,Hong Chen,Qipeng Yu,Baohua Li
Polymer electrolytes have attracted great attention due to their promising abilities, however, only on further improving their safety and electrochemical performance can they be used as next generation electrolytes. Here, a novel composite polymer electrolyte (CPE) with nano-SiO2 acting as a cross-linking agent to form a 3D cross-linked network was synthesized to improve the electrochemical stability and mechanical ability. The novel CPE exhibited some excellent properties such as high ionic conductivity (4.65 × 10−3 S cm−1 at room temperature) with a broad electrochemical stability window (∼5.4 V vs. Li/Li+), high ionic transfer number (0.45), high mechanical robustness and flexibility (Young’s module ∼8.9 MPa, breaking strain 181%), and excellent interface stability. The lithium metal battery LiFePO4/CPE/Li was assembled and delivered a specific capacity of 160 mA h g−1 with a capacity retention of above 90% after 500 cycles at 1C. Furthermore, to cooperate with high voltage cathode materials LiNi0.8Co0.1Mn0.1O2 and LiNi0.5Mn1.5O4, the novel CPE still delivered superior cycling performance compared to traditional electrolytes.
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ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Sudip Kumar Lahiri,Pengcheng Zhang,Cheng Zhang,Lin Liu
Limited robustness is a serious drawback for superhydrophobic coatings and degrades the performance of superhydrophobic surfaces in practical applications. Although fluororeagents have excellent durability for superhydrophobicity, their use has been restricted due to various health and environmental concerns. In this work, we describe a facile and efficient fabrication strategy for creating robust fluorine-free superhydrophobic composite coatings that are prepared by a simple dip-dry method, in which the H3BO3-incorporated SiO2–alkyl-silane coatings are deposited on woven cotton fabric surfaces followed by polydimethylsiloxane modification. The coated surface shows a large water contact angle of 157.95 ± 2° and a small sliding hysteresis angle (SHA) of 3.8 ± 0.6°, demonstrating excellent superhydrophobicity. The coated fabric surface also exhibited robustness and durability, withstanding a tape-peeling test (under 48.05 kPa) for around 80 repetitions and sandpaper rubbing (loaded 100 g) for 40 cycles. Furthermore, the coated fabric surface displayed self-healing and oil–water separation capacities. The developed superhydrophobic coatings in this study are robust, environmentally benign, and easy to fabricate, showing promising applications in textile industries.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2019
·Vol. 136
·期 26
·47713
·
IF 2.188
Lichao Liu,Hang Zhao,Fei Wang,Ping Xue,Jing Tian
Rheological behaviors of ultrahigh-molecular-weight polyethylene (PE)/high-density PE/SiO 2 blends are investigated using parallel-plate rheometer and capillary rheometer. The molecular chain conformational change mechanism is used to explain flow instabilities during extrusion. The viewpoints are proposed: (1) critical shear rate depends on the relative strength of irreversible viscous loss and reversible elastic orientation for molecular chains in transverse velocity gradient field inside the die and (2) critical shear stress depends on the extent of molecular chain conformational change inside the die, and the ease of conformational recovery after leaving the die. Modified nano-SiO 2 particles are detected a certain interfacial adhesion in PE matrix. The interfacial interaction limits viscous flow inside the die and conformational recovery after leaving the die, thus causing not only the flow instabilities to occur prematurely on shear rate and delaying sharkskin on shear stress, but also an alternate “sharkskin-melt fracture” appearance after global extrusion fracture. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47713.
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ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Xiaobai Li,Hongwei Ma,Peng Wang,Zhenchao Liu,Jinwu Peng,Wei Hu,Zhenhua Jiang,Baijun Liu
The practical applications of phosphoric acid-doped polybenzimidazole (PA–PBI) as high-temperature proton exchange membranes (HT-PEMs) are mainly limited by their poor dimensional-mechanical stability at high acid doping levels (ADLs) and the leaching of PA from membranes during fuel cell operation. In this work, to overcome these issues, we fabricated novel cross-linked PBI networks with additional imidazole groups by employing a newly synthesized bibenzimidazole-containing dichloro compound as cross-linker and an arylether-type Ph-PBI as matrix. Ph-PBI featured by good solubility under high molecular weight offers satisfactory film-forming ability and mechanical strength using for the matrix. Importantly, the additional imidazole moieties in BIM-2Cl endow the cross-linked PBI membranes improved dimensional-mechanical stability with simultaneously enhanced ADLs and proton conductivity. Furthermore, superior acid retention capability is obtained by incorporating porous polyhydroxy SiO2 nanoparticles into these cross-linked networks. As a result, the SiO2/cross-linked PBI composite membranes are suitable to manufacture membrane electrode assemblies (MEAs), and an excellent H2/O2 cell performance with a peak power density of 497 mW cm–2 at 160 °C under anhydrous conditions can be achieved.
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BIOSENSORS & BIOELECTRONICS
·
2019
·
IF 9.518
Hui-Fang Cui,Ting-Ting Zhang,Qi-Yan Lv,Xiaojie Song,Xiao-Jing Zhai,Gai-Gai Wang
A stable and sensitive electrochemical acetylcholinesterase (AChE) biosensor for detection of organophosphorus pesticides (OPs) was developed by doping Au nanorods (AuNRs)@mesoporous SiO 2 (MS) core-shell nanoparticles into CS/TiO 2 -CS (CS denotes for chitosan) immobilization matrix. AuNRs@MS core-shell nanoparticles were synthesized and characterized. The doping and the biosensor fabrication process were probed and confirmed by scanning electron microscopy and electrochemistry techniques. The doping conditions were optimized. The matrix both before and after AChE immobilization had a mesoporous nanostructure . The nanoparticles dispersed homogeneously within the matrix. The doping significantly enhanced the electro-conductivity of the TiO 2 -CS hydrogel, and dramatically improved the bioelectrocatalytic activity and OPs detection sensitivity of the AChE immobilized matrix. The detection linear ranges for both dichlovos (DDVP) and fenthion were from 0.018 μM (4.0 ppb) to 13.6 μM, and the limit of detection (LOD) was 5.3 nM (1.2 ppb) and 1.3 nM (0.36 ppb), respectively. The biosensor exhibited high reproducibility and accuracy in detecting OPs spiked vegetable juice samples. In addition, it exhibited very high detection stability and storage stability. The developed AChE biosensor was provided to be a promisingly applicable tool for OPs detection with high reliability, simplicity, and rapidness.
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Polymer-Plastics Technology and Materials
·
2019
·
IF 0
Bin Zhang,Yujie Jiang
Design and fabrication of SiO2@ammonium molybdate(AM) core-shell nanotubes are important for polylactic acid (PLA), these two components form a well-defined core-shell configuration that is distinct from simple core-shell or hybrid structures. The PLA was investigated by limiting oxygen index, vertical burning test and smoke density, cone calorimeter test, SEM and TGA. The results showed that SiO2@AM nanotube can effectively increase the flame retardancy and smoke suppression properties, and that it can apparently reduce heat release rate, total heat release and total smoke release. Furthermore, the addition of SiO2@AM nanotube brings better mechanical properties than the sample contain SiO2 nanotube. Here, SiO2@AM nanotube was considered to be an effective flame retardant in PLA.
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ENERGY & FUELS
·
2019
·
IF 3.021
Zhiming Huang,Ping Li,Xiao Luo,Xia Jiang,Lei Liu,Fan Ye,Jiazhe Kuang,Yue Luo,Yuanzhu Mi
In the current study, novel environmentally friendly and interfacially active carbon nanotubes/SiO2 nanomaterials (CNTs/SiO2) for emulsified crude oil separation were prepared via grafting nano-SiO2 on the surface of oxidized carbon nanotubes (Ox-CNTs). The structure of the as-prepared CNTs/SiO2 was characterized by Fourier transform infrared spectroscopy, UV–visible absorption spectra, Raman spectra, X-ray diffraction spectra, thermogravimetric analysis, field-emission scanning electron microscope, and energy-dispersive X-ray spectroscopy. Besides, three-phase contact angles (θ) were employed to evaluate the wettability of CNTs/SiO2. Also, it was found that the θ value of CNTs/SiO2 was about 90°. The nanomaterials with interfacial activity can spontaneously assemble at the oil–water interface, thus improving the droplet coalescence in the emulsion. Afterward, the demulsification performance was evaluated in crude-oil emulsions using the bottle test, which demonstrated that the demulsification efficiency demulsification efficiency could reach 87.40%. Also, the water phase was clear, while the optimum concentration and sedimentation time were 500 ppm and 30 min, respectively. Furthermore, the possible demulsification mechanism was evaluated by an optical microscope. The findings in this work might provide a novel environmentally friendly and interfacially active nanomaterial as a crude oil demulsifier.
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MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Amin Deng,Jun Yuan,Chenze Qi,Yong Gao
In this study, the templated fabrication of hollow SiO 2 microspheres with thiol-rich surfaces and their application as adsorbents for toxic metal ions were demonstrated. (Cyclohexane + TEOS)-in-water Pickering emulsion was first prepared employing detachable polyurethane- g -poly (N,N-dimethyl acrylamide) (PU- g -PDMA) copolymer micelles as emulsifiers. The subsequent Pickering emulsion interface directing sol-gel reaction of TEOS led to the formation of SiO 2 microspheres. Hydrophobic PU cores of PU- g -PDMA copolymer emulsifier micelles were in-situ entrapped in the formed SiO 2 layers, while hydrophilic PDMA shells were completely exposed on the surfaces of the SiO 2 shells, forming polymer brush-like structure. The subsequent removal of PDMA shells through the cleavage of the reversible disulfide linkages between PU core and PDMA shells left a large number of thiol groups on the surfaces of hollow SiO 2 microspheres. The resulting hollow SiO 2 microspheres with thiol-rich surfaces, described as SiO 2 @SH in the text, demonstrated a promising recyclable adsorption for toxic metal ions. ~88% of adsorption capacity for Pb 2+ has been maintained after four cycles of adsorption-desorption. The structure of hollow SiO 2 @SH microspheres was carefully characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy , respectively.
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Scientific Reports
·
2019
·Vol. 9
·期 1
·1-9
·
IF 4.011
Yang Yushan,He Haishan,Li Yougui,Qiu Jian
Robust, buoyant, superhydrophobic PVB/SiO 2 coatings were successfully formed on wood surface through a one-step solvothermal method and a nanoimprint lithography method. The as-prepared PVB/SiO 2 /wood specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermogravimetric/differential thermogravimetric (TG–DTG) analyses. The superhydrophobic property and abrasion resistance of rose-petal-like wood were measured and assessed by water contact angle (WCA) and sand abrasion tests. The results show that PVB/SiO 2 /wood not only exhibited a robust superhydrophobic performance with a WCA of 160° but also had excellent durability and thermostability during the sand abrasion tests and against corrosive liquids. Additionally, the as-prepared PVB/SiO 2 /wood specimens show high buoyancy.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Xinna Gao,Xueyan Wang,Zheng Yang,Yuhua Shen,Anjian Xie
A novel multi-functional yolk-shell SiO 2 @TiO 2 /CDs(y-STCs) nanocomposite with interesting structure of SiO 2 cores, porous TiO 2 shell, and cavities was synthesized by using a simple method. The experimental results indicate that the yolk-shell structure and modification of carbon dots (CDs) play important roles in the enhancement of SERS signals and photocatalytic performance. The y-STCs nanocomposite used as the SERS substrate showed excellent efficiency and reproducibility for the detection of rhodamine 6G (R6G). The detection limit of R6G was shown to be as low as 6 × 10 −8 M. Furthermore, the fabricated y-STCs nanocomposite utilized as the photocatalytst for the degradation of dinitraphenols (DNP) can greatly shorten reaction time to 120 min compared with previous studies, and the DNP degradation rate could reach 96% under simulated sunlight irradiation. The y-STCs nanospheres also possessed excellent cycle stability for the photocatalytic degradation of DNP. Thus, the bi-functional y-STCs nanocomposite may have potential applications in the detection and photocatalytic degradation of organic pollutants.
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Arabian Journal of Chemistry
·
2018
·
IF 2.969
Du Yue,Jiaheng Lei,Lina Zhou,Xiaodi Du,Zhenran Guo,Junsheng Li
Ordered meso/macroporous H 3 PW 12 O 40 /SiO 2 nanocomposites with high specific surface areas were prepared using cationic surfactant and monodispersed polystyrene spheres (PS) as dual-template. The characterization results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption-desorption, and small-angle XRD patterns confirmed the existence of ordered meso/macroporous structure and the wide-angle XRD patterns, Fourier transform infrared spectroscopy (FTIR), X-ray photoemission spectroscopy (XPS) measurements suggested the high dispersivity of the Keggin-type heteropolyacid (HPA) on silica matrix. There was an optimum value of cationic surfactant usage and proper calcination temperature of ordered meso/macroporous H 3 PW 12 O 40 /SiO 2 catalyst leading to ultra-high specific surface areas. Furthermore, the ordered meso/macroporous H 3 PW 12 O 40 /SiO 2 catalyst was evaluated for ultra-deep oxidative desulfurization (ODS) of cyclic sulphur-containing compounds using hydrogen peroxide (H 2 O 2 ) as oxidant. Under optimum reaction conditions, dibenzothiophene (DBT) could be removed within 100 min at 30 °C by meso/macroporous H 3 PW 12 O 40 /SiO 2 catalyst. The excellent catalytic activity should be attributed to the combination of ordered meso/macroporous architecture and high surface area of H 3 PW 12 O 40 /SiO 2 catalyst which promoted the mass transport of reactants and products in the pore channel and provided more accessible catalytic active sites. In addition, the meso/macroporous H 3 PW 12 O 40 /SiO 2 catalyst showed good stability with only 1.9% efficiency decreased after 6 cycles.
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