Preparation of acrylic resin/modified nano-SiO<Subscript>2</Subscript> via sol-gel method for leather finishing agent

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%.     

离子交换树脂悬浊液的介电弛豫谱研究

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.     

粘鼠胶的成分分析

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。     

氮丙啶交联剂的交联性能及固化动力学研究

合成了一种氯丙啶交联剂，并以丙烯酸树脂乳液为模型化合物对交联剂的交联性能及固化动力学进行了研究。结果表明：在丙烯酸树脂乳液中加入适量的氯丙啶交联剂，可使胶膜的力学性能及耐水碱性，耐溶剂性都得到很大的提高；但交联对玻璃化转变温度的影响较小。用程序升温DSC（差示扫描量热法）方法对固化反应动力学进行了研究，计算出固化反应的活化能。     

Selective photochemical cleavage of an α-ketoamide in a highly functionalised macrolide ascomycin

A novel photochemical amide cleavage reaction of (6S)-methoxyascomycin opening a pathway for the selective cleavage of the pipecolic acid, is described. The scope of this reaction with several analogues carrying suitable protecting groups is examined.     

Synthesis and anion recognition of neutral receptors based on multiamide calix[4]arene

Two multiamide calix[4]arenes (5, 6) were synthesized and characterized by NMR, MS and elemental analysis. The binding properties of receptors with some anions (π-O₂NPhOPO₃²⁻, π-O₂NPhO⁻, H₂PO₄⁻, Ac⁻, Cl⁻, Br⁻ and I⁻) were studied by UV-Vis spectra. The results indicate that the tetraamide calix[4]arenes (5, 6) have a good selectivity to the anions containing aromatic ring (π-O₂NPhOPO₃ ²⁻, π-O₂NPhO⁻). The 1 : 1 complexes between host and guest were formed through multiple hydrogen bonding and π-π interactions. The hosts 5 and 6 also show a definite binding ability for the anions (H₂PO₄⁻, Ac⁻, Cl⁻) that have no ultraviolet absorption, which provides a simple method of spectrum detection for these anions.     

Liquid chromatography of isomers of aromatic acids on microbore column packed with anion-exchange resin

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.     

Phosphorus based epoxy terminated structural adhesive 2. Curing, adhesive strength and thermal stability

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.     

A chelating resin containing bis(2-benzimidazolylmethyl)amine: synthesis and metal-ion uptake properties suitable for analytical application

A new stable chelating resin was synthesized by incorporating the bis(2-benzimidazolyl methyl)amine into Merrifield polymer through CN 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.     

ICP-AES法测定高纯氧化铕中稀土杂质元素

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。