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排序方式: 共有150条查询结果,搜索用时 22 毫秒
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Achille M. Bivigou-Koumba Eckhard Görnitz André Laschewsky Peter Müller-Buschbaum Christine M. Papadakis 《Colloid and polymer science》2010,288(5):499-517
Several series of symmetrical triblock copolymers were synthesized by the reversible addition fragmentation chain transfer
method. They consist of a long block of poly(N-isopropylacrylamide) as hydrophilic, thermoresponsive middle block, which is end-capped by two small strongly hydrophobic
blocks made from five different vinyl polymers. The association of the amphiphilic polymers was studied in dilute and concentrated
aqueous solution. The polymer micelles found at low concentrations form hydrogels at high concentrations, typically above
30–35 wt.%. Hydrogel formation and the thermosensitive rheological behavior were studied exemplarily for copolymers with hydrophobic
blocks of polystyrene, poly(2-ethylhexyl acrylate), and poly(n-octadecyl acrylate). All systems exhibited a cloud point around 30 °C. Heating beyond the cloud point initially favors hydrogel
formation but continued heating results in macroscopic phase separation. The rheological behavior suggests that the copolymers
associate into flower-like micelles, with only a small share of polymers that bridge the micelles and act as physical cross-linkers,
even at high concentrations. 相似文献
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The title redox couple, in noncoordinating perchlorate medium, has been used to probe the electrochemical behavior of different IrO2-based electrodes; pure oxide electrodes, as well as IrO2-SnO2 mixtures, have been investigated. The obtained results show that the electrode material strongly affects the electrochemical response. A tentative explanation, based on the different point of zero charge of the considered oxides, is presented. 相似文献
36.
Augusto De Renzi Achille Panunzi Michaelangelo Scalone Aldo Vitagliano 《Journal of organometallic chemistry》1980,192(1):129-132
Amination of PtII-allene complexes of the type cis[PtCl2(Me2CCCHR)(PPh3)] gives the new four-membered C, N chelate aminoalkenyl complexes [Me2(PPh3)Cl]. These undergo ready insertion of carbon monoxide into the CPt σ-bond; the resulting acyl complexes are oxidized by hydrogen peroxide to aminoacidato complexes, and the free unsaturated β-aminoacids can be recovered in good yield by ligand displacement. 相似文献
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Gian Paolo Boldrini Achille Umani-Ronchi Mauro Panunzio 《Journal of organometallic chemistry》1979,171(1):85-88
The tetraethylammonium undecacarbonylhydridotriferrate [(C2H5)4N+ HFe3(CO)11?] (I): which can be easily prepared in a two-step sequence from iron pentacarbonyl, triethylamine and tetraethylammonium chloride, selectively reduces nitroarenes to amines and α, β-unsaturated carbonyl compounds to the corresponding saturated compounds both in good yield. I reacts with some organic halides to give dehalogenated products. 相似文献
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A method to extract and analyze organic compounds from water is presented. A solid phase micro-trap (micro-SPE) directly connected to the micro-analytical column is used. Sensibility and specificity needed for trace analysis are guaranteed by mass spectrometric electron ionization (EI) detection. A new micro-HPLC/EI-MS interface called Capillary-EI (Cap-EI) is described. The ultimate evolution of this interface is also presented: in this extremely simplified interface the analytes are nebulized, vaporized and ionized in the small volume of the ion source. This interface, called Direct-EI, exploits nano- and micro-HPLC columns with a mobile phase flow rates ranging from 0.3 to 1.5 microL/min. Contemporary use of micro SPE, Cap-EI or Direct-EI gives us a powerful technique to identify and quantify organic pollutants at part per billion level (ppb). 相似文献
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