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931.
Amarildo Otavio Martins 《Analytica chimica acta》2004,521(2):157-162
This study describes the functionalization of biopolymer chitosan, using the complexing agent 8-hydroxyquinoline (oxine) by reaction of diazotization. The chelating resin was characterized by degree of deacetylation, infrared, Raman spectroscopy. The efficiency of the chelating resin and accuracy of the proposed method was evaluated by the metal ion recovery technique in the analysis of potable water, lake water, seawater and a certified sample of oyster tissue. The metal ions Cd(II) and Cu(II) in the samples were previously enriched in a minicolumn and flow injection flame atomic absorption spectrometry (FI-FAAS) determined the concentrations of the analytes. The chelating resin exhibited high selectivity for Cd(II) at pH 7 and for Cu(II) at pH 10. The eluent concentration was tested by the use of HNO3 in concentrations of 0.1-3 mol l−1 maximum response was obtained at 0.5 mol l−1 for Cd(II) and Cu(II), with R.S.D. values of 0.4%. The analytes gave relative standard deviations (R.S.D.) of 1.5 and 0.7% for solutions of Cd(II) and Cu(II), respectively (n = 7) containing 20 μg l−1 of the metal ions, defining a high reproducibility. The limits of detection (LOD) were 0.1 μg l−1 for Cd(II) and 0.4 μg l−1 for Cu(II). The analytical properties of merit were obtained using the parameters previously optimized with preconcentration time of 90 s. The chelating resin showed chemical stability within a wide range of pH and the efficiency was not altered for the preconcentration of the metal ions during all the experiments. 相似文献
932.
Jian Zhong Ma Jing Hu Zong Sui Yang Lingyun Liu 《Journal of Sol-Gel Science and Technology》2007,41(3):209-216
Acrylic resin/nano-SiO2 (AR/nano-SiO2) composite was prepared by physical blends of acrylic resin (AR) and nano-SiO2, which was synthesized via the sol-gel method of tetraethoxysilane (TEOS) catalyzed with alkali. The synthetic conditions,
such as surfactant type, the content of nano-SiO2 sol, stirring speed, mixed temperature and ultrasonic treatment, on nanocomposites’ property were studied in detail. DSC
indicated the glass transition temperature of AR/nano-SiO2 (Tg = −26.7°C) was a little higher than that of the acrylic resin (Tg= −29.6°C). Water uptake confirmed that the water resistance
of AR/nano-SiO2 was improved by 55.94% and the solvent resistance by 54.79% when compared with AR. The improved properties of leather finished
by AR/nano-SiO2 were shown, in contrast to AR treatment; water vapor permeability was increased by 9.15% and the finish adhesion by 10.35%. 相似文献
933.
离子交换树脂悬浊液的介电弛豫谱研究 总被引:2,自引:0,他引:2
研究了D354阴离子交换树脂分散在不同浓度KCl溶液中的悬浊液的频率域介电谱,发现在测量频率为106~107 Hz处出现了显著的介电弛豫现象,得出了介电常数、电导率以及弛豫时间随KCl溶液浓度的特异的变化关系,理论分析表明,该弛豫是一个以界面极化为主的非单一极化机制的弛豫过程,进而利用Maxwell-Wagner界面极化理论和双电层性质解释了该体系的特异介电行为,得到了树脂悬浊液在外加交变电场下的离子迁移和聚集信息,并确定了该树脂在静态平衡下双电层中对离子的相对离子强度. 相似文献
934.
使用各种分离、分析手段剖析粘鼠胶的组成,首先使用适当溶剂,通过分级沉淀分离粘鼠胶的各组分。然后用傅立叶变换红外光谱仪、核磁共振波谱仪对分离后的组分进行结构鉴定。 相似文献
935.
936.
Summary A low-capacity, anion-exchange, porous-polymer resin was used as the packing material in a microbore column. Using a phosphate buffer containing various organic modifiers, retention behavior of substituted benzoic acid isomers with amino, chloro, methyl, nitro and carboxylic groups was investigated. The effect of ethanol, acetonitrile and sodium dodecylsulfate used as organic modifiers on the retention behavior at various eluent pH values was studies and optimum separations of the positional isomers reported. 相似文献
937.
Phosphorus based epoxy terminated structural adhesive 2. Curing, adhesive strength and thermal stability 总被引:1,自引:0,他引:1
Sankar Prasad BhuniyaSukumar Maiti 《European Polymer Journal》2002,38(1):195-201
The curing behavior of phosphorus based epoxy terminated polymers was studied using diaminodiphenyl ether, diaminodiphenyl sulfone, benzophenone tetracarboxylic dianhydride and the commercial hardener of Ciba-Geigy's two-pack araldite, as curing agent. The adhesive strength of these adhesives was measured by various ASTM methods like lap-shear, peel, and cohesive tests on metal-metal, wood-wood and wood-metal interfaces. All these results were compared with the synthesized epoxy resins prepared from bisphenol-A and epichlorohydrin having the epoxy equivalent value of 0.519. The thermal stability of both the virgin resin and its cured form was also studied by thermogravimetric analysis. 相似文献
938.
A new stable chelating resin was synthesized by incorporating the bis(2-benzimidazolyl methyl)amine into Merrifield polymer through CN covalent bond and characterized by elemental analysis, IR and thermal study. The sorption capacity of the newly formed resin for Ag(I), Cu(II), Fe(III), Hg(II) and Pb(II) as a function of pH have been studied. The resin exhibits no affinity for alkali or alkaline earth metals. In column operation it has been observed that Ag(I) in trace quantities can be separated from different complex matrices and Hg(II) can be removed from the river water spiked with Hg(II) at usual pH of natural waters. 相似文献
939.
ICP-AES法测定高纯氧化铕中稀土杂质元素 总被引:1,自引:0,他引:1
研究了锌粉还原 5709萃淋树脂分离富集 ICP AES法测定高纯氧化铕中14个稀土杂质元素的方法,用ICP AES法测定稀土元素工作曲线下限为(以氧化物计)镧为0.05mg·L-1,铈、镨、钇为0.25mg·L-1,钕、钐、铽、镝、钬为0.1mg·L-1,铒、铥、镱、镥、钇为0.05mg·L-1,回收率为90%~106%。方法简便、准确、快速,可用于99.99%氧化铕中14个稀土杂质元素的测定。 相似文献
940.
Scrap car tyre particles can be used as filler or toughening agent in rigid epoxy matrices if the resultant interface is adequate. The objective of this work was to investigate the effects of use of different silane coupling agents (SCAs) to improve the interface between the epoxy resin and recycled rubber particles. For this purpose, seven different SCA were used to modify surfaces of the rubber particles. After the preparation of epoxy-rubber specimens, tensile Charpy impact and plane-strain fracture toughness tests were conducted. Mechanical tests and fractographic studies revealed that some of the SCA can improve of the interface between the epoxy matrix and the rubber particles leading to increases in strength while slight decreases in toughness of the samples. 相似文献