排序方式: 共有19条查询结果,搜索用时 21 毫秒
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Meifang Liu Xin ZhangMauro Zammarano Jeffrey W. GilmanTakashi Kashiwagi 《Polymer Degradation and Stability》2011,96(5):1000-1008
A combination of montmorillonite (MT) clay and catalysts was used to explore possible synergistic effects in reducing the flammability of poly(styrene-co-acrylonitrile) (SAN). Several catalysts, including ammonium phosphomolybdate hydrate (NHPMo), melamine phosphomolybdate hydrate (MEPMo), zinc phosphomolybdate hydrate (ZnPMo) and sodium phosphomolybdate hydrate (NaPMo), were used. The combination of MT (Cloisite 20A) with NHPMo showed synergistic enhancement in improving the char formation and reducing the peak mass loss rate of SAN40 as compared with SAN40 composites containing MT or NHPMo alone, while similar synergistic performance was not obtained between MT and NaPMo or ZnPMo or MEPMo. The better flame retardancy with this combination is probably due to the two primary aspects. One is the increased catalytic activity of the combination of Cloisite 20A and NHPMo probably due to the overlapping degradation temperature range of the combination of 20A/NHPMo and SAN40, which probably results in more char formation; the other is more NHPMo being around or on the clay stacks while less is in the galleries of the clay; this probably bridges the clay stacks and strengthens the clay network with char formed during the degradation process. High temperature rheological data confirmed the formation of a stronger network structure in SAN40/20/NHPMo; this benefits flame retardancy by allowing fewer cracks to form in the outer char layer on the polymer mass. The more continuous char layer suppresses bubbles transport of fuel vapors and heat transfer through the char layer, thereby reducing the mass loss rate. 相似文献
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A novel sensor have been constructed by layer‐by‐layer hybridizing phosphomolybdate (POM) and poly(ferrocenylsilane) (PFS) on a cysteamine modified gold electrode. The properties and performance of the sensor have been measured by electrochemistry and atomic force microscopy in detail. The results showed that the constructed multilayers modified gold electrode combined the properties of POM and PFS, and exhibited good electrocatalytic ability to a series of inorganic ions, including BrO , IO , NO , Fe3+, ascorbic acid and SO . The well catalytic activity of the sensor was ascribed to the porous structure of hybrid POM‐PFS multilayer. The resulted sensor exhibited extremely fast amperometric response, low detection limit, high selectivity and wide linear range to these analyses. 相似文献
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The molybdenum blue reaction, used predominantly for the determination of orthophosphate in environmental waters, has been perpetually modified and re-optimised over the years, but this important reaction in analytical chemistry is usually treated as something of a 'black box' in the analytical literature. A large number of papers describe a wide variety of reaction conditions and apparently different products (as determined by UV–visible spectroscopy) but a discussion of the chemistry underlying this behaviour is often addressed superficially or not at all. This review aims to rationalise the findings of the many 'optimised' molybdenum blue methods in the literature, mainly for environmental waters, in terms of the underlying polyoxometallate chemistry and offers suggestions for the further enhancement of this time-honoured analytical reaction. 相似文献
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《Journal of Coordination Chemistry》2012,65(3):275-283
A novel molybdenum phosphate complex, [Ni(1)(en)2(PO4)2Mo5O15][Ni(2)(en)2- (H2O)2]?·?H2en?·?3H2O (1), has been synthesized under hydrothermal conditions. The complex was characterized by elemental analysis, FT-IR, DTA/TG and single crystal X-ray diffraction. The compound is orthorhombic, space group P212121, with a?=?12.580(3), b?=?17.676(4), c?=?17.969(4)?Å, V?=?3995.5(15)?Å3, Z?=?4, and was refined to R 1?=?0.0301, wR 2?=?0.0715. It possesses an unprecedented one-dimensional chain structure constructed from molybdenum phosphate clusters and nickel complex fragments. 相似文献
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固体石蜡碳糊—磷钼酸根电极的研制与应用 总被引:1,自引:0,他引:1
研究了以固体石蜡作粘和剂的碳糊电极,在磷钼酸溶液中活化一定时间后,该电极对1.0×10~(-6)~5.0×10~(-4)mol·L~(-1)的磷钼酸有能斯特响应,斜率约为30mV,检出限为3.2×10~(-7)mol·L~(-1).电极的稳定性和选择性较好,已用于矿石、水样中磷的测定,结果满意. 相似文献
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Magdalena Skunik Beata Baranowska Dina Fattakhova Krzysztof Miecznikowski Malgorzata Chojak Alexander Kuhn Pawel J. Kulesza 《Journal of Solid State Electrochemistry》2006,10(3):168-175
Using the layer-by-layer technique, carbon submicroparticles, that have been modified and stabilized with monolayers of Keggin-type
phosphododecamolybdate (PMo12O403−), can be dispersed in multilayer films of organic polymers, poly(3,4-ethylenedioxythiophene), i.e., PEDOT, or poly(diallyldimethylammonium)
chloride, i.e., PDDA, deposited on glassy carbon or indium-tin oxide conductive glass electrodes. The approach involves alternate
treatments in the colloidal suspension of PMo12O403−-covered carbon submicroparticles in the solution of monomer, 3,4-ethylenedioxythiophene or in solution of PDDA polymer. Electrostatic
attractive interactions between anionic phosphomolybdate-modified carbon submicroparticles and cationic polymer layers permit
not only uniform and controlled growth of the hybrid organic–inorganic film but also contribute to its overall stability.
The system composed of PMo12O403−-covered carbon submicroparticles dispersed in PEDOT is characterized by fast dynamics of charge transport and has been used
to construct symmetric microelectrochemical redox capacitor. The PDDA-based system has occurred to be attractive for electrocatalytic
reduction of hydrogen peroxide. 相似文献
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Preparation of Keggin‐type phosphomolybdate by a one‐step solid‐state reaction at room temperature and its application in protein adsorption 下载免费PDF全文
Qing Chen Li‐Ming Shen Jie Xia Xu‐Wei Chen Jian‐Hua Wang 《Journal of separation science》2014,37(19):2716-2723
Keggin‐type phosphomolybdate ((C19H42N)3PMo12O40) is prepared by a one‐step solid‐state reaction at room temperature and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, and elemental analysis. The as‐prepared phosphomolybdate is demonstrated to be an efficient adsorbent for proteins. In this particular case, the selective adsorption of neutral protein hemoglobin is achieved. While under the same conditions virtually no adsorption of acidic and basic proteins, represented by bovine serum albumin and cytochrome c, are observed. A solid‐phase extraction procedure is developed for the selective isolation of hemoglobin. At pH 6, a sorption efficiency of 91.4% is achieved for 100 μg/mL hemoglobin in 1.0 mL solution by using 5.0 mg of the phosphomolybdate. The adsorption behavior of hemoglobin fits well with a Langmuir adsorption model, corresponding to a theoretical adsorption capacity of 55.86 mg/g. The retained hemoglobin could be readily recovered by using a 60 mmol/L imidazole solution at pH 7, giving rise to a recovery of 64.7%. The practical application of phosphomolybdate for protein adsorption is demonstrated by the selective isolation of hemoglobin from human whole blood followed by a sodium dodecyl sulfate polyacrylamide gel electrophoresis assay. 相似文献