环型聚苯乙烯结构与性能的研究

本文通过多种分析测试手段，详细研究了环型聚苯乙烯（ＲＰＳ）分子链结构、聚集态结构、热性能及稀溶液性质，并与线型聚苯乙烯（ＬＰＳ）作了对照。结果表明：ＲＰＳ链结构确为环状结构，由于链结构不同于ＬＰＳ，因此链刚性及其随分子量的变化关系也不同于ＬＰＳ，这是导致其性质与ＬＰＳ存在很大差异的根本原因。ＲＰＳ链堆积较ＬＰＳ松散，由于线团密度ＲＰＳ大于ＬＰＳ，所以宏观上二者比容并无多大差异，但ＲＰＳ比容受分子量影响较ＬＰＳ大。ＲＰＳ的Ｔｇ随分子量变化关系受自由体积和构象熵即链刚性两种因素的影响。动态光散射及小角Ｘ光散射实验结果说明，ＲＰＳ的扩散行为、流体力学半径和无扰分子尺寸与ＬＰＳ相比有很大不同。     

FOF-18结构与性能的量子化学研究

用B3LYP法,在6-31G基组水平上优化了FOF-18的几何构型,得其稳定的几何构型;在振动分析的基础上求得体系的振动频率、IR谱;采用Monte-Carlo方法预估了密度;设计等键等电子反应计算了生成焓;运用Kamlet公式预测爆速、爆压和爆热;将计算性能与CL-20的性能作比较。结果表明,FOF-18整个分子呈N字形,且存在7个强吸收峰,密度2.06g/cm3、生成焓501.03kJ/mol、爆速9411.82m/s、爆压42440.76MPa、爆热6637.46kJ/kg,该化合物的性能与CL-20接近。     

Efficient usage of highly dispersed Pt on carbon nanotubes for electrode catalysts of polymer electrolyte fuel cells

A Pt-deposited carbon nanotube (CNT) shows higher performance than a commercial Pt-deposited carbon black (CB) with reducing 60% Pt load per electrode area in polymer electrolyte fuel cells (PEFCs) below 500 mA/cm². K₂PtCl₄ and H₂PtCl₆·6(H₂O) are used for the Pt deposition onto multi-walled CNTs (MWCNTs), which are produced by the catalytic decomposition of hydrocarbons. The electric power densities produced using the Pt/CNT electrodes are greater than that of the Pt/CB by a factor of two to four on the basis of the Pt load per power. CNTs are thus found to be a good support of Pt particles for PEFC electrodes. TEM images show 2–4-nm Pt nanoparticles dispersed on the CNT surfaces. These high performances are considered to be due to the efficient formation of the triple-phase boundaries of gas–electrode–electrolyte. The mechanisms of Pt deposition are discussed for these Pt-deposited CNTs.     

银型抗菌沸石的合成

沸石类抗菌材料是一种无机多功能材料，具有耐酸，耐碱，过滤除污，吸附除臭以及长效广泛的杀菌和抑菌效果，主要介绍液相，固相离子交换法将具有抗菌性能的银离子与沸石合成为抗菌沸石，用正交法确定两种方法的较佳条件，并进行比较，用红外光谱对沸石原样与抗菌沸石进行比较分析，同时对合成的抗菌沸石进行了抗菌性能测试。     

不饱和酸结构对不饱和聚酯树脂固化行为的影响

通过IR分析了用顺酐和反酸与聚酯合成不饱和聚酯树脂的反应机理,讨论了二种树脂体系固化放热曲线不同的原因。     

Comparison Between a Pt–Rh/Ba/Al2O3 and a Newly Formulated NOX-Trap Catalysts Under Alternate Lean–Rich Flows

In situ FT-IR spectroscopy coupled with mass spectrometry have been used to study the mechanism of nitrates formation and reduction over a common Pt–Rh/Ba/Al₂O₃ NO _x storage catalyst, compared with a different alumina-based compound.The experimental device used consists of a transmission reactor cell (having a very small dead volume) dedicated to the evolution of surface species, and of a mass spectrometer combined with a FT-IR micro-cell for gas analysis, allowing time resolved analysis in stationary and transient conditions.At the first time the nitration properties of the catalysts under a lean flow have been studied in the appropriate temperature window (473–673 K). The dynamics of nitrates formation has been pointed out, as well as the different coordination sites on the compounds surface. Then the catalysts have been alternatively exposed to rich and lean flows very close to the real exhaust composition. This has allowed the identification of reduction pathway, active sites, intermediate species and by-products for NO _X -trap reaction. In particular, we have differentiated the role of the support and of the noble metal in the mechanism, as well as of isocyanate adspecies and ammonia among the detected species. The very high NO _X storage properties and the selectivity (near 100%) in nitrogen of the newly designed catalyst have been pointed out.     

RF sputter deposition of poly(tetrafluoroethylene) films as masking materials for silicon micromachining

Polymers have been studied extensively because of their wonderful array of properties. Their properties can be tailored by many means and can be made useful in many ways. Polymers can be crosslinked or branched and can provide different properties, such as conduction and passivation. This study dealt with the RF sputter deposition of poly(tetrafluoroethylene) (PTFE) films with the aim of using them as masking materials during the fabrication of various micromachined structures. The films were deposited on silicon substrates at different plasma powers (100, 150, and 200 W) for a constant deposition time (60 min). To test the masking properties, the deposited films were immersed in a 20 wt % aqueous KOH solution at 80°C for 60 min. The films showed lower contact angles and interfacial tension, and this indicated good adhesion of the films to the silicon substrates. Good adhesion is an essential quality of masking materials during micromachining. The structural properties of the as‐deposited and etched films were studied with Fourier transform infrared and X‐ray photoelectron spectroscopy. These indicated that the bonding groups and binding energies of C? F and C? CF matched the reported values well. Furthermore, the presence of C? F and C? CF bonds, even after the etching of silicon substrates in highly alkaline KOH solutions for 60 min, showed that the PTFE films remained unchanged in the etchant and, therefore, could function as good masking materials during the fabrication of micromachined structures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1183–1192, 2004     

Infrared studies of the interaction of carbon monoxide and dinitrogen with ferrisilicate MFI-type zeolites

Fourier transform IR spectroscopy of CO and N₂, adsorbed at liquid nitrogen temperature, was used to characterize an MFI-type H-FeZSM-5 ferrisilicate which was synthesized with a Si/Fe ratio of 50. Thermal treatment of this material at 773 and 973 K was performed in order to follow formation of extraframework species. On samples fired at 773 K Brønsted acid sites were present which gave an O-H stretching band at 3630 cm^–1. These hydroxyl groups formed adducts with both probe molecules, which were monitored by the corresponding bathochromic shift, . Corresponding values for adsorbed CO and N₂ were = –270 and = – 100, respectively. Increasing the firing temperature up to 973 K led to complete removal of iron from the zeolite framework, and consequent disappearance of Brønsted acidity. In this process, extraframework iron oxide species were formed which were also characterized by IR spectroscopy of the adsorbed probe molecules. Both CO and N₂ gave Lewis-type adducts with coordinatively unsaturated Fe³⁺ ions present in the extraframework material. A comparison is made with results of a previous study on the H-GaZSM-5 isomorph.     

二苯并噻吩合成方法的改进

对文献报道的由联苯和硫在AlCl3催化下反应合成二苯并噻吩(DBT方法中的提纯过程作了改进，大大简化了提纯步骤，使制备DBT的时间缩短了一半，产率为63．4％，经提纯后的成品含量达99．7％，其纯度、外观、晶相均优于进口试剂，但成本远低于进口试剂。产品用FT-IR、LRS、XRD和^1H NMR表征结果与文献报道完全相符合。     

Isotopic Oxygen Exchange and EPR Studies of Superoxide Species on the SrF2/La2O3 Catalyst

By using the in situ IR spectroscopy, the superoxide species (O₂⁻), characterized by the O–O stretching peak at 1130 cm⁻¹, was detected on the SrF₂/La₂O₃ catalyst at temperatures up to 973 K. The introduction of ¹⁸O₂ isotope caused the 1130 cm⁻¹ peak to shift to lower wavenumbers (1095 and 1064 cm⁻¹), consistent with the assignment of the spectra to the superoxide species. A good correlation between the rate of the disappearance of the O₂⁻ species and that of the formation of C₂H₄ was observed, suggesting that O₂⁻ was the active oxygen species responsible for the oxidative coupling of methane (OCM) on the SrF₂/La₂O₃ catalyst. This conclusion was reinforced by the EPR experiments (g_xx = 2.0001, g_yy = 2.0045, g_zz = 2.0685), showing that O₂⁻ was the only paramagnetic oxygen species detectable on the O₂-preadsorbed SrF₂/La₂O₃ catalyst. These results suggest that superoxide O₂⁻ can be a stable active oxygen species, whose role in the OCM reaction cannot be overlooked.