Polymers from 12-hydroxymethyltetrahydroabietic acid and its vinyl and acrylate esters

12-Hydroxymethyltetrahydroabietic acid has been homopolymerized by melt condensation and homopolyester has been obtained. Vinyl 12-hydroxymethyltetrahydroabietate has been prepared from 12-hydroxymethyltetrahydroabietic acid by vinyl interchange procedure with vinyl acetate, and has been homopolymerized, copolymerized with vinyl chloride, vinyl acetate, and terpolymerized with styrene and acrylonitrile. The acrylate ester of 12-hydroxymethyltetrahydroabietic acid also has been prepared from 12-hydroxymethyltetrahydroabietic acid and acrylyl chloride. The acrylate thus obtained has been homopolymerized and copolymerized with vinyl chloride and vinyl acetate. Polymers thus obtained have been characterized.     

A fluorimetric and circular dichroism study of hemoglobin--effect of pH and anionic amphiphiles

In this work, bovine hemoglobin (Hb) has been studied mainly by the fluorescence method. pH has been found to exert a profound effect on Hb structure. This has been confirmed by fluorescence and circular dichroism (CD) studies. The pH-induced change in quaternary structure of Hb indirectly affects its secondary structure. This in turn affects ligand binding to Hb at various pH. The binding of two amphiphiles, a bile salt and a surfactant, have been investigated. The pH-induced structural modification of Hb has been confirmed by studies with the well-known denaturant urea and the polarity probe ANS, which has been used as an extrinsic fluorophore.     

Improvement of properties of silica‐filled styrene‐butadiene rubber composites through plasma surface modification of silica

The performance of plasma surface modified silica filler in styrene‐butadiene rubber (SBR) matrix has been analyzed. The conditions of plasma modification have been optimized by taking secant modulus as a standard parameter and the occurrence of the modification has been confirmed by surface area determination and Fourier transform infrared spectroscopy. The plasma‐modified surface of silica has been found to be composed of carbon–carbon double bonds and carbon–hydrogen bonds. Silane treatment also has been carried out on silica filler surface for a comparative assessment of its influence in the curing behavior and filler–rubber interaction. The cure reactions of all the rubber compounds have been found to be proceeded according to first‐order kinetics. A reduction in the cure reaction rate constant has been observed with the loading of unmodified and surface modified silica, emphasizing the cure deactivation of the matrix rubber by the silica filler. The filler dispersion, as revealed by scanning electron microscopy, has been found to be greatly improved by the plasma as well as silane treatment. The filler–rubber interaction has been found to be greatly improved by both surface treatments, but the best balance of mechanical properties has been observed with plasma surface modification only. Copyright © 2004 John Wiley & Sons, Ltd.     

A new nebulizer for atomic spectrometry

The rotating disc nebulizer has been redesigned with respect to the principle parameters that determines its analytical performance. The flow pattern of the aerosol attained has been optimized by altering the shape of the inner chamber of the nebulizer to obtain optimum aerodynamic characteristics. The optimum angle of impact and "free flight" distance has been established using particle size distribution and mass transport efficiency as criteria. Analytical characteristics have been determined by monitoring the emission signal from aqueous standards. The accuracy has been assessed by using reference steel samples. Using standard solutions of different viscosity the performance of the nebulizer with respect to viscosity changes of the sample has been compared with that of a commercial Meinhardt nebulizer. The rotating disc nebulizer has been less affected by changes in viscosity making it possible to use this nebulizer with slurry and oil samples.     

Preparation of thin films comprising palladium nanoparticles by a solid-liquid interface reaction technique

A new approach to the formation of palladium nanoparticulate films with diameter between 6 and 50 nm by the solid-liquid interface reaction technique (SLIRT) has been presented. A solid film of palladium nitrate was formed by the modified spin coating method. This film is subsequently immersed in a reducing solution to initiate a reaction at the interface and ultimately transforms it to a palladium metal film. The kinetics of palladium reduction has been studied by UV-visible spectroscopy. The characterization of the palladium film has been performed by various physicochemical techniques such as XRD, ED, XPS, SEM, EDX, TEM, and UV-visible spectroscopy. The texture and morphology of the materials has been investigated by atomic force microscopy (AFM). At a constant palladium nitrate concentration, the average diameter of palladium nanoparticles decreases with an increase of hydrazine concentration. The effect of concentration of hydrazine on the particle size has been discussed. The palladium film formation mechanism has been proposed for the SLIRT.     

超声幅照下ABS塑料表面的粗化研究

由于外层镀有金属的塑料制品兼有塑料及金属材料的优点,因而是一类具有广泛用途的新型复合材料。其中以金属化的ＡＢＳ塑料的应用最为广泛。＊＊Ｓ塑料金属化的方法很多,其中以电镀法最受重视ｌ‘］。为保证金属镀层与塑料表面具有良好结合力,使塑料表面形成四坑、微孔等均匀微观粗糙状态的粗化工艺是相当关键的步骤之一ｐ‘。现国内外广泛采用铬一硫酸混合液的化学粗化法,但该法对环境污染较大。随着环保要求的日益高涨,其它粗化法越来越受到人们的重视［’］。本文探索了利用超声波的空化效应来粗化ＡＢＳ塑料表面、为ＡＢＳ塑料的电…     

Alpha-cyclodextrin functionalized CdS nanocrystals for fabrication of 2/3 D assemblies

Different types of cyclodextrins (CDs) have been tested as mediators for the water phase transfer of organic-capped CdS nanocrystals (NCs), and alphaCD has been demonstrated to be the most effective system. The formation of a complex based on alphaCDs and colloidal NCs has been considered to be responsible for the phase transfer process and extensively investigated by optical, structural, and calorimetric measurements, as a function of the experimental parameters (pH and NC and CD concentration). A mechanism for the complexation phenomena has been suggested. The fabrication of 2/3 D supramolecular architectures has been proposed according to two different strategies. First, a layer-by-layer procedure has been used to obtain multilayered structures where polyelectrolyte layers have been intercalated with negatively charged alphaCD-CdS NC complexes by exploiting electrostatic interaction between polyelectrolyte and cyclodextrin OH groups. Second, a monolayer of CdS NCs has been deposited onto a self-assembled monolayer of sulfated CDs, thus combining the use of an electrostatic-force-based approach and host-guest chemistry. The important role played by host-guest interactions has then been revealed.     

113mIn radioisotope generator system

Tin-indium generator systems were made with commercial hydrated zirconium oxide, silica gel and hydrated zirconium oxide prepared by the AMPHLETT method. The adsorption capacity of tin has been determined by both spectrophotometric analysis and gammaspectrometry. Zirconium break-through has been determined and compared with the literature values. The dependence of the adsorption capacity on the particle size has been investigated. The effect of autoclaving on the generator systems has been examined.     

Kinetics and mechanism of the production of higher olefins from stearic acid in the presence of an alumina-supported nickel sulfide catalyst

A nickel sulfide catalyst which efficient in the decarbonylation of fatty acids to olefins and dienes has been obtained for the first time by treating alumina-supported nickel sulfate with hydrogen, and its properties have been studied. In its presence, the olefin selectivity of the reaction can exceed 90%. The kinetics of stearic acid deoxygenation to heptadecenes has been investigated, a kinetic model has been constructed, and a mechanism has been proposed for the reaction over this catalyst. Olefin oligomerization is the dominant side reaction. Kinetic evidence for the catalytic inhibition of oligomerization by nickel hydrides formed on the catalyst has been obtained. The compositions of active site–reactant adsorption complexes have been discussed.     

量子化尺寸纳米颗粒及其在生物体系中的作用

本文从胶体化学与物理化学的角度介绍了纳米颗粒的尺寸量子化效应。介绍了作者所进行的纳米颗粒在生物体系中的应用工作。纳米颗粒金和二氧化硅能显著地提高葡萄糖氧化酶的生物活性。纳米颗粒金能提高视黄醛仿生膜的光电响应电流和寿命。作者用纳米颗粒的吸附浓集效应、吸附定向效应、和量子尺寸效应来解释这些效应     

Dimerization of 1-Isopropenylnaphthalene: Structural Study of the Dimer

1-Isopropenylnaphthalene has been dimerized by cationic initiation. The structure of the dimer does not depend on the initiator. The cyclization of the dimeric ion takes place on carbon 8 (peri). The structure has been established both by x-ray diffractometry and by NMR. The complete crystallographic structure has been determined. The dimers of various substituted isopropenylnaphthalenes have been obtained in the same way and have the same structure.     

Determination of the surface potential for hollow-fiber membranes by the streaming-potential method

A procedure has been proposed for measuring the surface potential of hollow-fiber membranes by the streaming-potential method under the conditions of a tangential flow of a solution. The zeta-potential and surface charge of nanofiltration hollow-fiber polyacrylonitrile membranes have been measured. The measurements have been performed for membranes with different porosities, which were obtained by partial drying of initial humid membranes. The porosity has been determined from the electrical conductivity of a membrane. An equation has been proposed for calculating the charge transfer by a solution flow in a porous layer. It has been shown that the use of the proposed equation makes it possible to obtain more correct values of the membrane surface potential.     

Charge storage performance of doped carbons prepared from polyaniline for supercapacitors

Doped carbons have been prepared from polyaniline for supercapacitors. The morphology of samples has been characterized by scanning electron microscope, the surface chemical composition of samples has been investigated by X-ray photoelectron spectroscopy, and the surface area of samples has been calculated by Brunauer–Emmett–Teller measurement. Electrochemical properties have been studied by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements in 6 mol L⁻¹ potassium hydroxide. Their charge storage performance has been evaluated, and the effect of nitrogen atomic functionalities on the pseudocapacitive property has been studied. The experimental results have proved two mechanisms of energy storage in doped carbons: double-layer formation and pseudocapacitance. The overall specific capacitance of doped unactivated carbon is mainly attributed to pseudocapacitance, that of doped activated carbon prepared by physical activation is attributed to the synergic effect of pseudocapacitance and double-layer capacitance, but that of doped activated carbon prepared by chemical activation is mainly attributed to double-layer capacitance.     

Indirect atomic absorption spectrophotometric determination of arsenic

Arsenic has been determined indirectly by atomic absorption spectroscopy by estimating molybdenum in a solution of arsenomolybdic acid in methyl isobutyl ketone. Interference from other ions has been eliminated by prior extraction of arsenic as the diethyldithiocarbamate in diethyl ether. Arsenic has been determined in the presence of phosphate, silicate and germanium (IV). The method has also been used for the determination of arsenic in organic material.     

Synthesis, characterization, and thermal study of polyaniline composite with the photoadduct of potassium hexacyanoferrate (II) involving hexamine ligand

The present paper involves the synthesis of polyaniline (PANI) composite with photoadduct of potassium hexacyanoferrate (II) involving hexamine as a ligand and cobalt chloride as a complexing agent via in situ oxidative polymerization by ammonium persulphate. The photoadduct has been synthesized by photoirradiation followed by substitution with the hexamine ligand. The final product has been isolated by using CoCl₂ as complexing agent. Viscosity average molar mass has been determined by viscosity method using Ostwald’s viscometer. The photoirradiation, substitution, and successful synthesis have been proved by recording pH, UV–visible spectra before and after irradiation, and FTIR of the photoadduct. The composite based on the synthesized photoadduct has been subjected to FTIR, X-ray diffraction, and SEM characterization techniques. Thermal analysis has been done by using TG and DSC technique. FTIR absorption peaks confirm the insertion of photoadduct in the backbone of PANI. SEM of the composite also supports its successful synthesis. The XRD of photoadduct shows crystalline structure, which has remained dominant in the composite, hence proving the successful synthesis of PANI composite with photoadduct. Thermal analysis shows high thermal stability of photoadduct which in turn has improved the thermal stability of PANI composite, therefore, shows the potential of composite for high-temperature application purposes.     

The solution behavior of poly(vinylpyrrolidone): its clouding in salt solution, solvation by water and isopropanol, and interaction with sodium dodecyl sulfate

This article deals with the solution properties of poly(vinylpyrrolidone) (PVP) in salt and surfactant environment. The cloud point (CP) of PVP has been found to be induced by the salts NaCl, KCl, KBr, Na2SO4, MgSO4, and Na3PO4. On the basis of CP values for a salt at different [PVP], the energetics of the clouding process have been estimated. The effect of the surfactant, sodium dodecyl sulfate (SDS), on the salt-induced CP has also been studied, and reduction in CP at low [SDS] and increase in CP at high [SDS] have been observed. The water vapor adsorption of PVP has been determined by isopiestic method. The results display a BET Type III isotherm whose analysis has helped to obtain the monolayer capacity of PVP and formation of multilayer on it. The solvation of PVP in a solution of water and a water-isopropanol mixture has been determined by conductometry from which contribution of the individual components were estimated. The interaction of PVP with SDS in solution led to formation of a complex entity, which has been studied also by conductometry adopting a binding-equilibrium scheme. SDS has been found to undergo two types of binding as monomers in the pre- critical aggregation concentration (CAC) range and as small clusters in the post CAC region. The stoichiometries of binding and binding constant were evaluated.     

Surface and in-depth characterization of TiC/C and Ti(C,N) layers by means of AES and Factor Analysis

Magnetron sputtered TiC/C multilayers and Plasma Vapour Deposited Ti(C,N) layers have been investigated by AES. The carbon sensivity factor has been calibrated for the correct composition of a TiC standard sample. Nitrogen has been measured indirectly based on the Ti(L3M23M23)/Ti(L3M23V) peak area ratio in the direct E.N(E) spectrum using Ti, TiC and TiN standard samples. The influence of Tougaard background removal has been tested. As the less accurate method taking the Ti peak-to-peak ratio has been found to give adequately good results. It has been possible to recalculate AES depth profiles, where only peak-to-peak values and no peak areas in the direct spectrum are available. Factor Analysis has been applied to AES depth profiling results. The data matrix in each column contains the linked experimental spectra of the measured elements. Based on the standard spectra the main components of a TiN layer on silicon have been identified by Factor Analysis. The structure of a TiC/C multilayer system has been resolved by the characteristic C(KLL) peak shape in C and TiC. Factor Analysis enables to calculate the individual profiles for Ti, TiC and C.     

Diels-Alder reaction of anthracene on carbosilane dendrimer

The dendritic macromolecule with 4, 8, 16 and 32 bicyclo end groups on the periphery has been created by the Diels-Alder reaction of anthracene and maleimide. The dendritic skeleton with triple bonds has been prepared by the hydrosilation and the alkynylation of bis(phenylethynyl)dimethylsilane as a core. The peripheral anthracene on dendrimers has been substituted by the reaction of chlorosilyl groups containing dendritic generations and 9-anthracenecarbinol. NMR and MALDI-TOF mass spectrum has characterized these Diels-Alder products.     

Extraction of uranium, thorium and lanthanides using Cyanex-923: Their separations and recovery from monazite

The extraction behavior of uranium, thorium and lanthanides, represented by cerium and ytterbium, by Cyanex-923 has been investigated. The effect of different variables like the concentration of acids, metal ion and extractant, nature of diluent and temperature has been studied. A composition for the extracted U(VI) and Th(IV) species has been proposed. Based on the partition data some important binary and ternary separations involving the aforesaid metal ions have been achieved. The proposed procedure has been applied for the recovery of uranium, thorium and lanthanide fraction from monazite sand. The stability and regeneration capacity of the extractant have been evaluated.     

Synthesis and microstructure-mechanical property relationships of segmented polyurethanes based on a PCL-PTHF-PCL block copolymer as soft segment

The goal of this work has been the synthesis of novel materials based on a biodegradable polycaprolactone-block-polytetrahydrofurane-block-polycaprolactone diol (PCL-b-PTHF-b-PCL). The segmented thermoplastic polyurethanes (STPU) have been synthesised in bulk without catalyst at different molar ratios and their characterization has been performed by different techniques. The physic-chemical interactions, responsible for the unique polyurethane properties, have been evaluated by total attenuated Fourier transform infrared spectroscopy (ATR-IR) in the amide I region using a Gaussian deconvolution technique and, on the other hand, atomic force microscopy (AFM) has been employed to determine the phase microstructures. The effect of increase the hard segment content (HS) has been discussed from the viewpoint of the miscibility of hard and soft segments, analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). The influence of HS content on the microstructure-mechanical property relationships has also been investigated. Special attention has been focused on the wettability of the samples, measured through water contact angle measurements (WCA), to determine the tendency for biocompatibility of the samples.