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81.
82.
R. WinterP.G. Nixon R.J. TerjesonJ. Mohtasham N.R. HolcombD.W. Grainger D. GrahamD.G. Castner G.L. Gard 《Journal of fluorine chemistry》2002,115(2):107-113
A new perfluorinated acrylate monomer containing the SF5(CF2)6-perfluorinated side chain was synthesized and polymerized into films. Bulk monomer characterization is consistent with the molecular structure based on FTIR, mass spectrometry and NMR analyses. The surface properties of polymer coatings were studied with aqueous wetting (contact angle) and X-ray photoelectron spectroscopy (XPS) methods. The surface composition is shown to be highly enriched in the terminal side chain SF5-chemistry and exhibits properties consistent with a highly apolar, non-wetting perfluorinated polymer surface. Depth-dependent XPS studies using angular-resolved methods (ADXPS) confirmed a non-stoichiometric enrichment of sulfur and fluorine at the film ambient interface, consistent with a surface presence of the terminal SF5-group and possibly film structural anisotropy in the surface zone. Time-of-flight (TOF) secondary ion mass spectrometry (SIMS) analysis supplements the XPS data by showing the presence of all expected SF5-acrylate chemistry components in the outer 15 Å of the film surface. 相似文献
83.
Yoichi M.A Yamada 《Tetrahedron》2004,60(18):4087-4096
A novel catalyst PWAA, an assembled complex of phosphotungstic acid (H3PW12O40) and a non-cross-linked copolymer of N-isopropylacrylamide with an ammonium, was developed. It is an amphiphilic, cross-linked, and supramolecular insoluble complex and showed catalytic activity on oxidation with aqueous hydrogen peroxide. PWAA, used in 2.7×10−5-2.0×10−3 mol equiv., catalyzed oxidation of allylic alcohols, amines, and sulfides efficiently. The turnover number (TON) of PWAA reached up to 35,000. PWAA showed a good stability in organic/aqueous media and was reused three to five times. 相似文献
84.
D-72 resin supported nickel-copper catalysts prepared by solvated metal atom impreg-nation (SMAI) were studied by magnetic measurements and X-ray photoelectron spectro-scopy (XPS). The Ni particles on the catalysts are very highly dispersed and displaysuperparamagnetic behaviour. Ni-Cu alloy clusters were found to be formed. The sur-face compositions are different from the bulk concentrations. In contrast with the surfaceenrichment in copper generally observed on conventional Ni-Cu catalysts, the surfaces ofthese catalysts are enriched in nickel. The nickel is in both zero and valent states, whilecopper is mainly in metallic state. Catalytic data show that the formation of Ni-Cu alloyclusters has a profound effect on the catalytic activities of the catalysts in the hydrogena-tion of furfural. The activity of the Ni:Cu ratio of one bimetallic catalysts is much higherthan that of the Ni or Cu monometallic catalyst. 相似文献
85.
A copolymer of poly(acrylonitrile-co-styrene) (SAN) was synthesized via an emulsion polymerization method. Novel polymer electrolyte membranes cast from the blends of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), SAN and fumed silica (SiO2) are microporous and can be used in polymer lithium-ion batteries. The membrane shows excellent characteristics such as high ionic conductivity and good mechanical strength when the mass ratio between SAN and PVDF-HFP and SiO2 is 3.5/31.5/5. The ionic conductivity of the membrane soaked in a liquid electrolyte of 1 mol/L LiPF6/EC/DMC/DEC is 4.9×10-3 S cm-1 at 25℃. The membrane is electrochemical stable up to 5.5 V versus Li /Li in the liquid electrolyte. The influences of SiO2 content on the porosity and mechanical strength of the membranes were studied. Polymer lithium-ion batteries based on the membranes were assembled and their performances were also studied. 相似文献
86.
87.
粘度法研究高分子溶液行为的实验改进(Ⅱ) 总被引:13,自引:0,他引:13
高分子在粘度计毛细管管壁上的吸附不仅会导致毛细管有效管径减小,而且可以导致毛细管界面性质发生显著改变,具体表现为测定高分子溶液流过时间t之前和之后纯溶剂的流过时间t0和t0′与高分子溶液流过时间t对浓度作图外推到浓度为零时的值t0^*并不一致。不同温度时聚乙烯吡咯烷酮(PVP)水溶液粘度测定结果表明,当吸附讷发子显著改变了毛细管界面性质时,需要将高分子溶液粘度测定方法由t/t0′改为t/t0^*。经过改进的粘度测定方法不仅更加普适合理,而且更加简单有效。 相似文献
88.
高聚物非等温结晶动力学 总被引:2,自引:0,他引:2
由于等温DSC法测定结晶动力学参数在实验上存在着一定的局限性,这些缺点可通过非等温DSC法来克服。本文基于上述观点介绍了高聚物非等温结晶动力学的理论和实验方法,并对影响动力学过程的一些因素进行了讨论,对非等温结晶动力学的最新情况及发展倾向,应用情况作了介绍。 相似文献
89.
A versatile process for the preparation of composite films consisting of magnetite (Fe3O4) nanoparticles embedded in a polyaniline (PANI) matrix is reported. Spectroscopic properties of polyaniline matrix (PANI-EB), polyaniline protonated with camphor sulfonic acid (PANI-CSA0.5) PANI-ES and PANI/Fe3O4-CSA0.5 composites were studied, both in the state of the solutions of m-cresol and in thin films processed from the same solvents. The results of these studies indicate that m-cresol can be used for PANI/Fe3O4 composite preparation. Such films show both reasonably high electrical conductivity and magnetic permeability. A controlled application of a magnetic field during the casting process resulted in the formation of the materials with an unusual combination of magnetic and transport properties. The obtained films show the behavior that can be explained by the presence of both ferromagnetic and paramagnetic phases. The superparamagnetic contribution, if any, is very small. Application of the external magnetic field during fabrication of the composites stimulates creation of the aggregates of magnetic particles which, although keeps conductivity at a relatively high level, leads to a small decrease of the conductivity value. 相似文献
90.
Nadine Metz 《European Polymer Journal》2007,43(4):1202-1209
Acetone oxime acrylate has been synthesized as a new active ester monomer. Free radical polymerization yielded a reactive polymer soluble in various organic solvents, such as chloroform, dioxane, DMSO, acetone, methanol, dichloromethane, DMF, and ethanol. Controlled radical polymerization of acetone oxime acrylate was successfully conducted using the RAFT, NMP and Iniferter method. Partly polymer analogous reaction with N-isopropylamine resulted in the reactive copolymer poly(N-isopropylacrylamide-co-acetone oxime acrylate), which featured a lower critical solution temperature (LCST) of 61 °C in water. Further, the reactivity of the copolymer was exemplary proven by complete reaction with ammonia yielding poly(N-isopropylacrylamide-co-acrylamide), which does not possess a LCST. 相似文献