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选用甲基三氯硅烷和苯基三氯硅烷为主要原料合成了梯形聚甲基倍半硅氧烷(有机硅树脂Ⅰ)和梯形聚苯基倍半硅氧烷(有机硅树脂Ⅱ).并进行了红外光谱和差热分析. 相似文献
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目的研究以四甲基铵基笼形聚倍半硅氧烷(Octa TMA POSS)为填料,制备壳聚糖基复合膜,对壳聚糖薄膜的水蒸气阻隔性能和力学性能进行改善。方法采用溶液共混流延法制备复合膜,测定其水蒸气透过系数、表面接触角、溶胀度、溶解度、吸附等温曲线、拉伸性能、成膜液流变性能、微观形貌和X射线衍射等。结果笼形聚倍半硅氧烷的加入可提高复合膜对水分子的阻隔性,尤其是质量分数为3%时,其水蒸气透过系数下降了15.9%。同时,壳聚糖薄膜的力学性能也得到改善,在质量分数低于5%时,壳聚糖薄膜的抗拉强度、弹性模量可同时得到提高。结论四甲基铵基笼形聚倍半硅氧烷的加入可改善壳聚糖薄膜的阻湿性能和力学性能,可大大提升其在食品包装领域的应用潜力。 相似文献
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首先采用硅烷偶联剂通过水解缩合反应方法合成氨基功能化倍半硅氧烷(POSS-NH2),利用其表面氨基通过表面接枝聚合方法在倍半硅氧烷表面接枝磺化聚苯胺以实现其共价功能化,将磺化聚苯胺功能化倍半硅氧烷和聚二甲基硅氧烷通过溶液共混,利用滴涂法在Q235钢材表面制备出疏水防腐涂层。通过核磁共振(NMR)和傅里叶转换红外光谱(FT-IR)对氨基功能化倍半硅氧烷和磺化聚苯胺功能化倍半硅氧烷的结构进行表征分析;利用光电子能谱(XPS)分析磺化聚苯胺功能化倍半硅氧烷的化学组成和元素含量比例;利用扫描电子显微镜(SEM)表征磺化聚苯胺功能化倍半硅氧烷的微观形貌,观察到表面形貌较规整、呈颗粒状、纤维较粗的结构;采用静态接触角测试分析了四种涂层的疏水性,制备出的共价功能化POSS/PDMS防腐复合涂层疏水性最佳,接触角达到115°;采用EIS电化学阻抗谱和Tafel极化曲线测试表征了四种涂层的耐腐蚀性能,结果表明:共价功能化POSS/PDMS防腐复合涂层的腐蚀电位更大,腐蚀电流密度较小,由此表明所制备的材料具有优异的防腐性能。并且发现涂层的接触角越大,防腐性能越好。 相似文献
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以乙烯基倍半硅氧烷与七甲基氢三硅氧烷(HMHTS)为原料,按照不同的配比,通过硅氢加成反应制备几种乙烯基倍半硅氧烷衍生物,然后将其与加成型液体硅橡胶进行混合固化,并利用1 H-NMR、XRD、UV-Vis和TG等仪器对固化产物的性能进行表征。结果发现:随着Vi-POSS衍生物结构中七甲基三硅氧基的增多,其与液体硅橡胶的相容性会越来越好,透光率可以达到85%以上;当Vi-POSS衍生物结构中保留2或4个乙烯基时,可以将液体硅橡胶的拉伸强度由3.72MPa提高到6.27MPa;同时还可以显著提高液体硅橡胶的热稳定性。 相似文献
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Humbul Suleman Abdulhalim Shah Maulud Zakaria Man 《International Journal of Thermophysics》2016,37(9):94
The solubility of carbon dioxide in aqueous alkanolamine solutions was investigated in the high gas loading region based on experimental measurements and thermodynamic modeling. An experimental phase equilibrium study was performed to evaluate the absorption of carbon dioxide in aqueous solutions of five representative alkanolamines, including monoethanolamine, diethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-1-propanol and piperazine. The carbon dioxide loadings of these solutions were determined for a wide range of pressures (62.5 kPa to 4150 kPa), temperatures (303.15 K to 343.15 K) and alkanolamine concentrations (2 M to 4 M). The results were found to be largely consistent with those previously reported in the literature. Furthermore, a hybrid Kent–Eisenberg model was developed for the correlation of the experimental data points. This new model incorporated an equation of state/excess Gibbs energy model for determining the solubility of carbon dioxide in the high-pressure–high gas loading region. This approach also used a single correction parameter, which was a function of the alkanolamine concentration. The results of this model were in excellent agreement with our experimental results. Most notably, this model was consistent with other reported values from the literature. 相似文献
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Amin Bemani Alireza Baghban Shahaboddin Shamshirband Amir Mosavi Peter Csiba Annamaria R. Varkonyi-Koczy 《计算机、材料和连续体(英文)》2020,63(3):1175-1204
In the present work, a novel machine learning computational investigation is
carried out to accurately predict the solubility of different acids in supercritical carbon
dioxide. Four different machine learning algorithms of radial basis function, multi-layer
perceptron (MLP), artificial neural networks (ANN), least squares support vector machine
(LSSVM) and adaptive neuro-fuzzy inference system (ANFIS) are used to model the
solubility of different acids in carbon dioxide based on the temperature, pressure, hydrogen
number, carbon number, molecular weight, and the dissociation constant of acid. To
evaluate the proposed models, different graphical and statistical analyses, along with novel
sensitivity analysis, are carried out. The present study proposes an efficient tool for acid
solubility estimation in supercritical carbon dioxide, which can be highly beneficial for
engineers and chemists to predict operational conditions in industries. 相似文献
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Synthesis and characterisation of cerium sulphide over optical fiber and its gas sensing application
A.K.C. Theoderaj I.D. Jacob M. Chitra 《Materialwissenschaft und Werkstofftechnik》2021,52(11):1248-1258
In this study, a cladding-modified optical fiber-based gas sensor is proposed for detection of carbon dioxide gas. Cerium disulphide (CeS2) is synthesised and coated by chemical bath deposition (CBD) route over the region in which cladding is removed. This synthesised cerium disulphide is characterised by x-ray diffraction (XRD), photoluminescence spectrum (PL), ultra violet-visible absorption spectrum, ultra violet -visible reflectance and transmittance spectrum, scanning electron microscope images (SEM) and energy dispersive x-ray spectrum (EDX). The response of the sensor is recorded for different concentrations of test gases (nitrogen dioxide and carbon dioxide) and the sensor's selectivity is compared and analysed. It is observed that cerium disulphide is more sensitive to carbon dioxide compared to nitrogen dioxide. 相似文献
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Supercritical fluid chromatography of PAHs was performed with pure carbon dioxide and helium headspace carbon dioxide at various cylinder fill levels. The retention times of the PAHs increased when helium headspace carbon dioxide was used as a carrier fluid relative to pure carbon dioxide. The increased retention times were affected by the level of the liquid phase present in the helium headspace carbon dioxide cylinder. As more liquid phase was removed from the cylinder, the effect of helium on the solvating power of CO(2) was reduced because the relative amount of helium dissolved in the liquid phase decreased. Furthermore, the effect of helium headspace carbon dioxide was investigated with methanol-modified carbon dioxide mobile phases for the analysis of steroids. We observed that the relative solubility of helium in carbon dioxide resulted in longer retention times when compared to pure carbon dioxide as the liquid level of carbon dioxide decreased. 相似文献
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The development of a cost effective CO2-based hydrometallurgical process was realized through examining the extraction performance of a nearcritical carbon dioxide/CO2-soluble alkylamine extraction system over a large range of temperatures, pressures, and compositions, as well as through characterizing the phase behavior of the highly CO2-soluble alkylamines. A most important discovery of this research is that Fluorolink exhibits a higher CO2
solubility than other fluorinated alkylamines examined in past efforts. Development of these novel polymeric chelating agents is of great utility since these CO2-philic materials show high solubilities of 15 wt% at 860 psi and 25 °C. In addition to its high thermodynamic affinity for carbon dioxide, Fluorolink was chosen as the model complexing agent because of its ability to target the zinc metal ions of interest and form stable metal complexes. The chelating power of the complexing agent is validated by the large formation constant for the zinc metal complex of 1.0×1013 and the quantitative zinc extraction efficiency of 99% attained using a hexane/Fluorolink extractant system. It is because of the materials high CO2 solubility as well as its chelating power that the complexing agent was capable of extracting zinc in quantitative amounts from aqueous solutions containing high metal loadings of 5,000 ppm while operating at relatively low system pressures of 1,500 psi and below. This analysis validated the extraction mechanism via examination of reagent partitioning behavior, existence of zinc in carbon dioxide, stoichiometry of complexation process, and identification of the anion responsible for charge neutralization. 相似文献
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Murzin A. A. Babain V. A. Shadrin A. Yu. Smirnov I. V. Lumpov A. A. Gorshkov N. I. Miroslavov A. E. Muradymov M. Z. 《Radiochemistry》2001,43(2):177-182
A number of procedures for determining the solubility of metal complexes in supercritical carbon dioxide (SC-CO2) were compared. The solubility of adduct of uranyl trifuoroacetylacetonate with pyridine at a pressure of 300 atm and a temperture of 60°C exceeds 100 g l-1 (26 mg of U per 1 ml of SC-CO2). Partial degradation of the adduct under these conditions was observed. 相似文献
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超临界二氧化碳循环可应用于火力发电、核能发电、太阳能热发电等多种发电技术领域,作为新型的动力循环系统替代目前广泛使用的汽轮发电机组或燃气轮机发电机组。在进入商业化应用之前,需要对超临界二氧化碳循环技术在各种应用场景下的优势及其潜在的社会和经济效益进行探讨。通过分析超临界二氧化碳循环的特点和优势,探索其与化石能源、核能、太阳能、生物质能、余热等各种热源相结合的可行性,提出多种发电系统方案,可为今后超临界二氧化碳循环的商业化应用提供参考。随着超临界二氧化碳循环技术不断成熟,设备成本进一步降低,其系统简化、结构紧凑、效率高等优势将更加突显。 相似文献
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Experiments to determine the solubility of methane and carbon dioxide in PA-11 have been performed in the temperature range 50--90 °C and the pressure ranges 50--150 bar for methane and 20--40 bar for carbon dioxide. In general, the results agree fairly well with previous experiments for similar polymers, as well as showing correct trends in terms of temperature and pressure. The solubility of the gases follows Henrys law-type behavior except for methane at very high pressures. Diffusivities were also measured for the same systems at the same conditions. While the diffusivities are subject to more uncertainty than the solubility measurements, the expected (Arrhenius) trends are observed. Agreement with other experimental data using different methods is also good.Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27,
2003, Boulder, Colorado, U.S.A. 相似文献
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When supercritical carbon dioxide is used for extraction of trace compounds from lipid-rich samples, the resulting extract can contain a substantial amount of lipid coextractive which interferes in the subsequent chromatographic analysis. In this case, a cleanup step, which is time-consuming, is required in order to remove or reduce the lipid content in the extract. In this study, we report on a new approach for the extraction of trace compounds which significantly reduces the quantity of lipid coextractives, thereby eliminating the need for a sample cleanup step. An autoclave high-pressure reactor equipped with a mechanical stirring device was used for mixing gases, such as carbon dioxide and nitrogen, to generate the desired fluid mixtures. The composition of the mixtures could be adjusted by two mass flow controllers prior to the autoclave mixing device. The generated carbon dioxide/nitrogen binary mixtures were then employed to facilitate supercritical fluid extraction (SFE) at high pressures and elevated temperatures. The pressurized CO(2)/nitrogen binary fluid mixture demonstrated sufficient solvation power for quantitative recoveries of trace fortified organophosphorus and incurred organochlorine pesticides from poultry fat while significantly reducing lipid solubility in the fluid. This allowed the development of a method that produced an extract with minimal lipid content that could be used directly for gas chromatographic analysis, thereby eliminating the need to clean-up the extract. 相似文献