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1.
陈海珍 《宁波大学学报(理工版)》2004,17(4):444-448
选用了钛酸丁酯、硬脂酸和乙二醇作为表面活性剂,采用表面化学修饰和表面物理修饰2种方法修饰纳米氧化钛,然后分散在乙二醇溶剂中形成溶胶溶液.并通过红外光谱仪、紫外分光计、原子力显微镜,分析了表面化学修饰后的纳米氧化钛表面化学结构的变化,观测了纳米氧化钛溶胶在乙二醇溶剂中稳定性.试验结果表明表面活性剂与纳米氧化钛的表面的不饱和键之间形成了新的化学结构,粒子表面可能接枝上有机长链,提高了纳米粒子在溶剂中的相容性.表面化学修饰后的纳米氧化钛与乙二醇溶剂形成了较稳定的溶胶体系,而且纳米溶胶粒径较小.表面活性剂添加量与纳米粒子添加量控制在(1~1.2):1时,可以获得纳米溶胶粒径较小,同时溶胶稳定性较好的纳米氧化钛-乙二醇溶胶体系. 相似文献
2.
Su Nee Tan Daniel Fornasiero Rossen Sedev John Ralston 《Colloids and surfaces. A, Physicochemical and engineering aspects》2004,250(1-3):307-315
The foam behaviour of low molecular weight polypropylene glycols (PPG) was investigated as a function of concentration and molecular weight (190–2000 g mol−1). For each polypropylene glycol, foam stability increases with concentration and passes through a maximum, beyond which foamability is suppressed as the solubility limit of the glycol is exceeded and droplets of glycol form. Light-scattering data as well as static and dynamic surface tension results provide the key information leading to these interpretations. A maximum in foamability was observed for the PPG molecules with increasing molecular weight (caused by a change in molecular conformation at the interface). This suppresses the Marangoni effect and leads to a decrease in foam stability. 相似文献
3.
The rotation-tunneling spectrum of the second most stable gGg′ conformer of ethylene glycol (1,2-ethanediol) in its ground vibrational state has been studied in selected regions between 77 and 579 GHz. Compared to the study of the more stable aGg′ conformer, a much larger frequency range was studied, resulting in a much extended frequency list covering similar quantum numbers, J?55 and Ka?19. While the input data were reproduced within experimental uncertainties up to moderately high values of J and Ka larger residuals remain at higher quantum numbers. The severe mixing of the states caused by the Coriolis interaction between the two tunneling substates is suggested to provide a considerable part of the explanation. In addition, a Coriolis interaction of the gGg′ ground vibrational state with an excited state of the aGg′ conformer may also contribute. Relative intensities of closely spaced lines have been investigated to determine the signs of the Coriolis constants between the two tunneling substates relative to the dipole moment components and to estimate the magnitudes of the dipole moment components and the energy difference between the gGg′ and the aGg′ conformers. Results of ab initio calculations on the total dipole moment and the vibrational spectrum were needed for these estimates. The current analysis is limited to transitions with quantum numbers J?40 and Ka?6 plus those having J?22 and Ka?17 which could be reproduced within experimental uncertainties. The results are aimed at aiding radioastronomers to search for gGg′ ethylene glycol in comets and in interstellar space. 相似文献
4.
高抗冲聚丙烯序列结构的综合表征 总被引:3,自引:0,他引:3
用高分辨^13C NMR、FTIR等手段获得了高抗冲聚丙烯的组成和序列分布等链结构方面的信息。用DSC、WAXD等方法研究了它们的结晶行为、熔融转变及晶体结构,多种方法相结合有效地表征了高抗冲聚丙烯的序列结构。 相似文献
5.
The synthesis of oligoethylene glycols of defined lengths possessing different end functionalities is described. The utility of these molecules towards the development of a generic membrane anchor is demonstrated. 相似文献
6.
文中用MNDO方法研究了三甲基膦和环氧乙烷加成产物裂解反应机理 相似文献
7.
Xiujie Li Weiping Zhang Shenglin Liu Xiuwen Han Longya Xu Xinhe Bao 《Journal of molecular catalysis. A, Chemical》2006,250(1-2):94-99
The interfacial interaction of Mo species with the HBeta zeolite was studied by multinuclear MAS NMR, XRD and N2 adsorption. As proved by the quantitative 27Al MAS NMR, this interaction is so strong as to dealuminate the framework of HBeta, and leads to a new peak appearing at −14 ppm, which indicates the formation of crystalline Al2(MoO4)3. This can also be detected by XRD measurements when the Mo loading is as high as 9.0 wt.%. The corresponding quantitative 29Si and 1H MAS NMR spectra show that the amount of silanols and Brønsted acidic sites decrease obviously with increasing Mo loading. This also reveals an interaction between Mo species and HBeta support through an oxygen bridge resulting from condensation with the hydroxyls on the support. At higher Mo loadings, the interaction is so strong that it results in an extraction of aluminum from the zeolite framework, and subsequently appearance of Al2(MoO4)3 and loss of Brønsted acidic sites. These can be correlated to the low catalytic activity of Mo/HBeta in metathesis of ethylene and 2-butylene to propylene. 相似文献
8.
研制了天然气和氧经偶联反应制环氧乙烷的Ag-Ba-Cs/Al2O3催化剂(NEO-1)。用N2+O2+C2H4和偶联产物气加氧作原料气,在250℃,空速2500h^-1时,乙烯转化率和EO选择性分别达到了30%和80%,NEO-1催化具有适宜的比表面和孔结构,用XPS分析发现,与新鲜的催化相比,经活化和反应后的催化剂表面的Ba,Cs原子浓度增高,并具有较多的吸附氧物种。 相似文献
9.
钯II催化CO/乙烯共聚加压原位红外光谱研究 总被引:1,自引:1,他引:1
聚酿以其优良的物理、化学性能及原料(CO乙烯)简单易得的优点,在世界范围内已引起人们的普遍关注.为寻找价廉的催化剂或改良高效或(11)一双磷催化剂以推动聚酮的工业化进程,必须对共聚机理进行深入的研究.S;,n[’,’1、DrentP]等人根据对产品主链和端基的分析首先 相似文献
10.
玻璃管负载纳米TiO2薄膜的制备及其对乙烯降解的研究 总被引:6,自引:0,他引:6
采用sol—gel技术,在细玻璃管表面制备了La掺杂复合TiO2薄膜,采用封闭循环装置考察了催化剂负载质量、镧掺杂量、热处理温度和湿度等因素对催化活性的影响.结果表明,随着薄膜层数的增加,乙烯降解率增加,UV-VIS在近紫外的吸收随层数的变化与之吻合;镧掺杂量为1.5%、热处理温度500℃催化剂活性最高,而湿度的增大有利于提高乙烯的降解率和降解速度. 相似文献