铈离子引发N-对甲苯基丙烯酰胺类聚合物膜上丙烯酰胺接枝共聚合的研究

合成了NTAAM,NTMAAM,NPMAAM功能单体,发现这类功能单体与铈离子组成的体系能引发丙烯酰胺聚合,带有这类功能单体的聚合物和共聚物铸成的膜,能用铈离子引发丙烯酰胺接枝共聚合。这可从反应后的膜比基膜有较大的吸水率、与水有较小的接触角,也可从扫描电子显微镜观察到表面上有凸起图象的高分子链,以及从膜表面的X射线光电子能谱所证实。同时研究了共聚物膜的组成、反应条件对接枝共聚合的影响。     

有机官能化MSU-x孔分子筛的界面特征

MSU- x是自 M41S系列介孔分子筛问世以来所合成的另一类新型介孔分子筛材料 ,它具有三维立体交叉排列的 " worm- like"孔道结构特征及采用中性模板剂、廉价无毒等诸多合成优点 [1～ 4],有着潜在的应用价值 .为了改善纯硅的介孔材料的表面和孔道性质 ,扩大其应用领域 ,除了在骨架引入金属离子或在其孔道中负载催化活性物质外 ,对介孔材料进行有机官能化制备无机-有机杂化材料改善其骨架和孔道性质是当前研究的热点之一 [5].正是由于活性有机基团的存在 ,使得这些材料可直接用于催化反应 ,或作为中间介质成为其它络合离子的主体 .由于有机基…     

Compehensive two-dimensional gas chromatography (GC×GC) and its applicability to the characterization of complex (petrochemical) mixtures

In general, petrochemical products contain only a limited number of chemical classes of compounds (sample dimensionality). The enormous number of individual components within these classes, however, soon puts limitations upon a single chromatographic technique when it comes to adequate characterization of these products. Comprehensive two-dimensional gas chromatography (GC×GC) clearly opens the possibility of estimating the composition of hydrocarbon mixtures in a far more detailed fashion than hitherto possible. Although the emphasis of papers of GCxGC thus far almost exclusively applies to the unsurpassed peak-capacity, in the oil industry there is a need for characterization, rather than for analyzing all the individual compounds. In principle a GCxGC system can provide an almost perfect match between its intrinsic properties and the dimensionality of oil samples. To establish the applicability of GCxGC towards petrochemical analytical challenges, a commercially aavailable prototype instrument was subjected to an exhaustive characterization of a typical hydrocarbon precess stream and a fast characterization of a light gas oil. Although there are no fundamental limitations towards the quantitative aspects of a GCxGC system, this paper confines itself to qualitative results only. Quantitative aspects of GCxGC will be published in a forthcoming paper.     

介孔分子筛的制备与苯加氢反应的催化性能

1992年美国Mobil公司的研究人员首次报道合成出具有规则孔结构的M41S系列介孔分子筛材料.由于介孔材料独特的性质,引起了人们极大的兴趣,在其合成与性能等方面进行了大量的研究,合成出了多种系列不同性能的介孔分子筛,并研究了介孔分子筛作为催化剂或催化剂载体在各类催化反应中的催化性能.     

SYNTHESES AND STRUCTURES OF POLYPHENYLSILSESQUIOXANES

Phenyltrichlorosilane was hydrolyzed both ifi. toluene and in ether from which two kinds of prepolymers were obtained with different structures, molecular weights, and molecular weight distributions. Polymers were prepared from the prepolymers in various polymerization conditions. The ladderlike, branched, and crosslinked structures formed under different polymerization conditions were characterized by means of FTIR, ~1H and ~(29)Si-NMR, and elemental analysis. Azeotropic distillation of solvents and H_2O formed during polymerization was found useful in removing H_2O from the system and high molecular weight products with perfect ladderlike structure were obtained.     

Citrate selectivity of poly(neutral red) electropolymerized films

The synthesis and the spectroscopic and potentiometric characterization of electropolymerized films obtained from neutral red (NR) on Pt surface are described. FT Raman and NMR spectroscopy were used for evaluation of the resulting poly(NR) layers. Then potentiometry was applied to study the characteristics of the complexation of carboxylates with the poly(NR) films. A potentiometric poly(NR) sensor showing high selectivity for citrate anion was employed for its determination in soft drinks.     

TiO_2/PVDF复合中空纤维膜的制备和表征

采用相转化法制备了二氧化钛 (TiO2 ) 聚偏氟乙烯 (PVDF)复合中空纤维膜 .应用牛血清白蛋白截留实验、扫描电子显微镜、热重分析、X射线衍射分别对复合膜的分离性能、微观结构、热稳定性和晶相组成进行了分析 .结果表明复合膜的性能与纯PVDF膜的相比有显著的改善 ,其中对牛血清白蛋白的截留率从 3 2 7%提高到 86 6 7% ,单根纤维的断裂应力从 3 35MPa提高到 4 70MPa ,提高了 4 0 3% .氮气吸附实验测定的孔径分布进一步表明复合膜的孔径分布变窄 ,孔径变小 .     

Characterization and determination of 28 elements in fly ashes collected in a thermal power plant in Argentina using different instrumental techniques

Different techniques were selected for comprehensive characterization of seven samples of fly ashes collected from the electrostatic precipitator of the San Nicolás thermal power plant (Buenos Aires, Argentina). Particle size was measured using laser based particle size analyzer. X-ray diffraction powder (XRD) analysis and scanning electron microscopy (SEM) were used to characterize the mineral phase present in the matrix consisting basically of aluminosilicates and large amounts of amorphous material. The predominant crystalline phases were mullite and quartz. Major and minors elements (Al, Ca, Cl, Fe, K, Mg, Na, S, Si and Ti) were detected by energy dispersive X-ray analysis (EDAX). Trace elements (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, V and Zn) content was quantified by inductively coupled plasma optical emission spectrometry (ICP OES). Different acid mixtures and digestion procedures were compared for subsequent ICP OES measurements of the dissolved samples. The digestion procedures used were: i) a mixture of FH + HNO₃ + HClO₄ (open system digestion); ii) a mixture of FH + HNO₃ (MW-assisted digestion); iii) a mixture of HF and aqua regia (MW-assisted digestion). Instrumental neutron activation analysis (INAA) was employed for the determination of As, Ba, Co, Cr, Ce, Cs, Eu, Fe, Gd, Hf, La, Lu, Rb, Sb, Sc, Sm, Ta, Tb, Th, U and Yb. The validation of the procedure was performed by the analysis of two certified materials namely, i) NIST 1633b, coal fly ash and ii) GBW07105, rock. Mean elements content spanned from 41870 μg g^− 1 for Fe to 1.14 μg g^− 1 for Lu. The study showed that Fe (41870 μg g^− 1) ? V (1137 μg g^− 1) > Ni (269 μg g^− 1) > Mn (169 μg g^− 1) are the main components. An enrichment, with respect to crustal average, in many elements was observed especially for As, V and Sb that deserve particular interest from the environmental and human health point of view.     

Synthesis and characterization of UV-curable polydimethylsiloxane epoxy acrylate

UV-curable polydimethylsiloxane epoxy acrylate (PSEA) was synthesized by hydrosilylation of allyl glycidyl ether with hydrogen-containing polydimethylsiloxane to give polydimethylsiloxane-type epoxy resin which modified with acrylic acid. The curing speed and the double bond conversion in the UV cured film were influenced by the purity of PSEA with Fourier transform infrared spectroscopy (FT-IR) measurements. The influences of the synthetic process, such as, the reaction temperature, the concentration of reactants and the catalyst which determined the purity and activity of resins were discussed in detail. The structures of this resin were characterized by ¹H-NMR and FT-IR spectra. The molecular weight was checked by gel permeation chromatography, and M_n is 45,000. The properties of the cured film were also investigated by thermogravimetric analyzer, dynamical thermal mechanical analysis, and etc. For example, tensile strength (6.9 Mpa), elongation (20%), hardness (A; 18), water absorption (24 h; 2%), weight loss (40 min, 300 °C; 5%) and etc.