Properties of ethylene-propylene copolymer/PA-1010 blends using ethylene-propylene copolymer-graft-acrylic acid as a compatibilizing agent

The modification of ethylene-propylene copolymer (EP) has been accomplished by radical EP-graft-acrylic acid (EP-g-AA) has been used to obtain ternary PA/EP/EP-g-AA blends by melt mixing. Different blend morphologies were observed by scanning electron microscopy; the domain size of the EP-dispersed phase in the polyamide 1010 matrix of compatibilized blends decreased compared with that of uncompatibilized blends. It is found that EP-g-AA used as the third component has a profound effect on the mechanical properties of the resulting blends. This behavior has been attributed to serious chemical interactions taking place between the two components. Thermal analysis shows that some thermal properties of PA in compatibilized PA/EP/EP-g-AA changed because of chemical reactions taken place during the blending process. Wide angle x-ray diffraction measurements also confirmed this result. (C) 1996 John Wiley & Sons, Inc.

Studies of Oxygen Reduction on Polycobaltprotoporphyrin Film with RRDE

The mechanism of oxygen reduction on polycobaltprotoporphyrin IX dimethyl ester (PolyCoPP) film has been studied by using the rotating ring(Au)-disk(pyrolytic graphite, PG) electrode (RRDE) technique. The PolyCoPP/PG electrode promotes the oxygen reduction via two-electron process which produces peroxide as a main product in O-2-saturated 0.1 mol.dm(-3) NaOH. Once HO2- has been formed, no further reduction to OH- takes place at the disk. When the disk potential shifts to more negative, either the direct reduction of O-2 to OH- or the further reduction of HO2- to OH- occurs.

SIMULTANEOUS DETERMINATION OF GUANINE, URIC-ACID, HYPOXANTHINE AND XANTHINE IN HUMAN PLASMA BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH AMPEROMETRIC DETECTION

A reversed-phase high-performance liquid chromatographic method with amperometric detection is described for the separation and quantification of uric acid, guanine, hypoxanthine and xanthine. The isocratic separation of a standard mixture of the compounds was achieved in 5 min on a Spherisorb 5 C-18 reversed-phase column, with a mobile phase of NaH2PO4 (300 mmol dm(-3) pH 3.0)-methanol-acetonitrile-tetrahydrofuran (97.8 + 0.5 + 1.5 + 0.2). Uric acid, guanine, hypoxanthine and xanthine were completely separated, with detection limits in the range 2-20 pmol per injection. The effect of pH and the composition of the mobile phase on the separation are described. The hydrodynamic voltammograms of these compounds were recorded at a glassy carbon electrode. The linear range of the calibration graph for each compound was: uric acid; 1-5000 mu mol dm(-3); guanine, 0.5-2000 mu mol dm(-3); hypoxanthine, 0.1-500 mu mol dm(-3) and xanthine, 0.5-5000 mu mol dm(-3). The within- and between-day precision was good. The uric acid and hypoxanthine content in human plasma was measured using the proposed method. Good recoveries of uric acid (97.9-103%), hypoxanthine (98.0-99.2%), guanine (96.0-98.3%) and xanthine (96.0-102%) were obtained from human plasma. The results of electrochemical detection were in good agreement with those of UV detection.

SYNTHESIS AND PHOTOCHROMISM IN SOLUTION OF PHENOXYNAPHTHACENEQUINONE DERIVATIVES

Two new phenoxynaphthacenequinone derivatives, 6-[4-(2-(4-hydroxyphenyl)isopropyl)phenoxy] -5,12-naphthacenequinone (7) and 6-[4-(potassium sulfophenylazo)phenoxy]-5,12-naphthacenequinone (8), were synthesized, and their photochromism in solution was investigated and compared with that of 6-phenoxy-5,12-naphthacenequinone (1). On the basis of the spectral data and the selective irreversible reaction of ammonia with the colored phenoxy-ana-naphthacenequinone, the concentrations of the ana forms at the photostationary state (PSS), achieved by 365 nm UV irradiation, and the molar extinction coefficients of the pure ana forms at 481-482 nm of compounds 1, 7 and 8 in dimethylsulfoxide (DMSO) were found to be 83 mol.% and 1.70x10(4) mol(-1) dm(3) cm(-1), 82 mol.% and 1.62x10(4) mol(-1) dm(3) cm(-1) and 16 mol.% and approximately 1.34x10(4) mol(-1) dm(3) cm(-1) respectively; the absorption spectra of the colored ana forms of 7 and 1 in DMSO were estimated; the rate;constants of photoconversion induced by 365 nm light were obtained. The results show the strong effect of the structure of the phenoxynaphthacenequinones on their photochromism in solution. In addition to DMSO solution, compound 7 exhibited normal photochromism in toluene, benzene, chloroform and a DMSO-ethanol mixed solvent, but not in dimethylformamide (DMF) in which a photoinduced reaction occurred between 7 and DMF or impurities.

Thermal decomposition processes of polyaniline and poly-o-toluidine investigated by direct pyrolysis mass spectrometry

The thermal decomposition of polyaniline(PAn) and poly-o-toluidine(POT) was studied by means of direct pyrolysis mass spectrometry(DM) and MS/MS, The results showed that both benzene-diamine and quinone-diimine units were produced, and the intensities of fragments corresponding to quinone-diimine units increased as the oxidation degrees increased, The mechanism of thermal decomposition of PAn and POT was given for the first time.

Synthesis and catalytic properties of layered double hydroxides pillared by heteropolyoxometalate

Layered double hydroxides (LDHs) pillared with heteropolyoxometalate have been synthesized via both restructuring of hydrotalcite-like compounds and direct anion exchange under microwave field. LDHs and their derivatives are both found to be efficient for alkylation of isobutane with butene with a higher butene conversion and selectivity towards C-8(0).

RHEOLOGICAL PROPERTIES FOR CONCENTRATED-SOLUTION OF CHITOSAN - DEPENDENCE OF SOLVENTS

Rheological properties for concentrated solution of chitosan were investigated in different solvents, such as HCOOH, CH3COOH, HCl and 0.2 mol.dm-3 CH3COOH+ 0.l mol.dm-3 CH3COONa aqueous solutions. It was shown that viscosities and flow behavior of the sol

STUDY ON COMPLEXES OF RARE-EARTH WITH L-PHENYLALANINE BY POTENTIOMETRY WITH CALORIMETRY

The stability constants and thermodynamic functions for complexes of rare earth with L-phenylalanine have been determined by potentiometry and calorimetry at 25-degrees-C and ionic strength of 0.15mol.dm-3(NaCl). Stability of the complexes shows the "Tetrad effect". The entropy change makes a predominant contribution to the stability of these complexes. The ligand is coordinated to rare earth ions through its -CO2- and -NH2 group, and dehydration of ions plays an important role in coordination reaction.

SERRS OF PHTHALOCYANINE DERIVATIVES LB MONOLAYER

SERRS of copper tetrakis(2,4-ditert-penthyl phenoxy) Phthalocyanine LB monolayer on Ag island film and RRS of the compound in solid state have been obtained. On comparison between the spectra, it is proposed that the macrocycle of the molecule on the Ag substrate is oriented parallel to the surface.

四苯基卟啉合钴电化学催化还原二卤代乙烷的研究

本文以电化学、薄层电化学,可见·紫外现场光谱电化学和计算机数字模拟等方法,研究了四苯基卟啉合钻在N,N-二甲基甲酰胺和1,2-二氯乙烷溶液中电化学催化还原1,2-二澳乙烷和1,2-二氯乙烷的电极过程,测定了平行催化反应速率常数分别为1.2×10~3和5mol~(-1)·dm~3·S~(-1).

STUDIES ON THE REACTION AND STRUCTURE OF THE COMPLEXES OF ALKALINE-EARTH METAL WITH CHLOROPHOSPHONAZO-DBC

In this paper, the reaction and structure of the complexes of alkaline earth metal (Ca, Sr, Ba) with 2-(4'-chloro-2'-phosphonazo)-7-(2', 6'-dibromo-4'-chlorophenylazo 1, 8-dihydroxy-3, 6-naphthalene disulfonic acid (Chlorophosphonazo-DBC) have been studied. This ligand has eight forms under different acidity. The protonation reactions take place at [H+] > 0.36 mol.dm-3. The ligand begins dissociations at pH > 0.5. Two protons are released in the complexes formation reactions(Me2+ + 2HI half-arrow-pointing-left and half-arrow-pointing-right MeL2 + 2H+). The stability constants of the complexes of Calcium, Strontium and Barium have been determined by Yoe-Jone method, Majumder-Chakrabartty method and calculation method. The order of the stability of complexes is as follows: Sr > Ba > Ca. The structure of the complexes have also been studied by infrared spectroscopy, Laser Raman spectroscopy, NMR, and EPR. The results show that these groups of N = N, PO3H2 and OH are active groups in the complex reactions. The structure of the complexes of Strontium, Barium and Calcium with chlorophosphonazo-DBC are represented and the reaction and the complex bonds are discussed in this paper.

溶液中铅(Ⅱ)的某些氮杂芳香碱配合物形成的热力学研究

本文用 pH-电位滴定法在以 KNO_3为支持电解质、离子强度为0.1 mol/dm~3,温度为15,25,35和45℃条件下,测定了Pb(Ⅱ)的α,α′-联吡啶(bipy)和邻二氮菲(phen)配合物的稳定常数.应用温度系数法求出了各配合物形成反应的热力学函数变化.着重讨论了配体的碱性与配合物稳定性的关系.

稀土元素-氨三乙酸-氨基酸混配型配合物的研究

为探索多元体系中稀土离子与氨基酸的配位作用,本文在25℃和0.15mol/dm~3(NPCl)离子强度条件下,用pH电位法测定了稀土—氨三乙酸分别与蛋氨酸、丝氨酸生成混配型配合物的稳定常数。讨论了上述混配型配合物稳定常数随稀土原子序数的变化规律以及钇的位置。