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991.
Xiaonan Zhu Yihu Song Shaohui Chen Peihua Du Qiang Zheng 《Polymer International》2011,60(9):1355-1361
An acrylate processing aid (ACR)‐based ionomer containing lanthanide (La(III)) ion was synthesized and the influences of the ionomer on thermal stability, fusion time, transparency and tensile properties of rigid poly(vinyl chloride) (PVC) were investigated. Results revealed that the ionomer with a suitable La(III) content behaved as a good stabilizer as well as processing aid to the rigid PVC product. The ionomer could accelerate fusion of PVC much more quickly than ACR because of the strong interaction between La(III) carboxylate and PVC. Moreover, it exhibited a stabilizing efficiency comparable to lanthanum and calcium stearates (LaSt3 and CaSt2). The composite stabilizer of ionomer/zinc stearate (ZnSt2) exhibited an ability to improve initial discoloration better than LaSt3/ZnSt2 and CaSt2/ZnSt2 because the ionomer could form a complex with ZnSt2 much more slowly than LaSt3 and CaSt2. The compounds stabilized using ionomer/ZnSt2 exhibited a transparency comparable to those stabilized using organotin or liquid barium/zinc stabilizers, which was much better than those stabilized using LaSt3/ZnSt2 and CaSt2/ZnSt2. Copyright © 2011 Society of Chemical Industry 相似文献
992.
In this study, NiCu composite coating was electrochemically deposited on a copper electrode (Cu/NiCu) and tested for hydrogen evolution reaction (HER) in 1 M KOH solution for long-term electrolysis with the help of cathodic current–potential curves and electrochemical impedance spectroscopy (EIS) techniques. The bulk and surface composition of the coating was determined using atomic absorption spectroscopy (AAS) and energy dispersive X-ray (EDX) analysis. The surface morphology was investigated by scanning electron microscopy (SEM). The effect of electrolysis on the corrosion behavior of the Cu/NiCu electrode was also reported. It was found that the NiCu coating had a compact and porous structure with good time stability. The HER activity of the coating was stable over 120 h electrolysis and the HER mechanism was not modified during the operation. The corrosion tests showed that the corrosion resistance of the Cu/NiCu electrode changed when a cathodic current was applied to the electrolysis system. 相似文献
993.
David R. Vernon Paul A. Erickson Chang-Hsien Liao Jon Hsu Hong-Yue Tang 《International Journal of Hydrogen Energy》2009
Hydrogen can be produced via steam reformation of many feedstocks. External heat sources provide the thermal energy required by the endothermic steam reformation reactions. Temperature control of the steam reformation reactor is critical to reactor performance and catalyst life. Closed-loop control systems are typically used to modulate the heat input rate based on a comparison between a set point temperature and a temperature measurement. The location of the temperature sensor relative to the heat input location is a choice made during reactor design that can have significant impact on reactor temperature control. 相似文献
994.
995.
A transient, three-dimensional computational investigation of coupled heat and mass transfer in an annular cylindrical hydrogen storage tank, equipped with fins and filled with MmNi4.6Fe0.4, is presented. The effects of different parameters such as length, thickness and thermal conductivity of fins and overall heat transfer coefficient on the hydrogen storage performance of the tank are studied. The predicted hydrogen storage capacity at different supply pressures showed good agreement with the experimental data reported in the literature. In addition, it is observed that the use of fins enhances heat transfer within the hydride bed and consequently 40% improvement of the time required for 90% storage can be achieved over the case without fins. 相似文献
996.
对近几年来聚烯烃功能性棚膜专用树脂、功能性助剂的开发以及功能性棚膜的加工配方和工艺研究进行了综述,指出采用棚膜专用树脂,选用受阻胺类复合耐老化体系、接枝反应型流滴防雾体系和稀土有机化合物转光体系等助剂,以及反应挤出成型技术是今后棚膜研究和生产的发展方向。 相似文献
997.
998.
Porous metals are of interest for their high surface area and potential for enhanced catalytic behavior. Electrodeposited NiCu thin films with a range of compositions were electrochemically dealloyed to selectively remove the Cu component. The film structure, composition, and reactivity of these samples were characterized both before and after the dealloying step using scanning electron microscopy, energy-dispersive spectroscopy, and electrochemical measurements. The catalytic behavior of the dealloyed porous Ni samples towards the hydrogen evolution reaction was measured and compared to that of the as-deposited samples. The dealloyed samples were generally more reactive than their as-deposited counterparts at low overpotentials, making the dealloying procedure a promising area of exploration for improved hydrogen evolution catalysts. 相似文献
999.
Anthony Garron Dariusz ŚwierczyńskiSimona Bennici Aline Auroux 《International Journal of Hydrogen Energy》2009
To our knowledge, the present study is the first investigation by liquid-phase calorimetry of the mechanism of hydrogen generation by hydrolysis of sodium borohydride catalyzed by Co2B nanoparticles generated in situ. The differential reaction calorimeter was coupled with a volumetric hydrogen measurement, allowing a simultaneous thermodynamic and kinetic study of the reaction. At the end of the reaction, the catalyst was characterized ex situ by TEM, XRD, magnetism, N2 adsorption, TGA–DTA, and the liquid hydrolysis products were analyzed by Wet-STEM and 11B-NMR. The in situ preparation method made it possible to form nanoparticles (<12 nm) of Co2B which are the active phase for the hydrolysis reaction. In semi-batch conditions, the Co2B catalyst formed in situ is subsequently reduced by each borohydride addition and oxidized at the end of the hydrolysis reaction by OH− in the presence of metaborate. A coating of the nanoparticles has been observed by calorimetry and physico-chemical characterization, corresponding to the formation of a 2–3 nm layer of cobalt oxide or hydroxide species. 相似文献
1000.
The aim of this work is to study the influence of the addition of different oxides to an alumina support, on surface acidity and platinum reducibility in platinum-based catalysts, as well as their effect on the activity and selectivity in CO preferential oxidation, in presence of hydrogen. A correlation between surface acidity and acid strength of surface sites and metal reducibility was obtained, being Pt-support interaction a function of the acid sites concentration under a particular temperature range. In platinum supported on alumina catalysts, CO oxidation follows a Langmuir-Hinshelwood mechanism, where O2 and CO compete in the adsorption on the same type of active sites. It is noteworthy that the addition of La2O3 modifies the reaction mechanism. In this case, CO is not only adsorbed on the Pt active sites but also on La2O3, forming bridge bonded carbonates which leads to high reactivity at low temperatures. An increase on temperature produces CO desorption from Pt surface sites and favours oxygen adsorption producing CO2. CO oxidation with surface hydroxyl groups was activated producing simultaneously CO2 and H2. 相似文献