Effect of ammonium salts on poly(ethylene terephthalate) materials

The study of the effect of solutions of ammonium salts of low concentrations on polyester fibre material showed that modification of the material with ammonia formed by thermal hydrolysis of ammonium salts differs from modification with ammonia obtained by the reaction of equimolar quantities of ammonium nitrate and sodium hydroxide and is similar to the process that takes place when ammonia is added to the working solution. Of the salts examined, ammonium fluoride in the concentration of 0.02–0.35 M at 130°C and 30-min process time is the most active modifying agent. In these conditions, ammonium fluoride and the products of its high-temperature hydrolysis — hydrogen fluoride and ammonia — have the strongest catalytic effect on hydrolysis of cyclic oligomers with formation of their linear form. On the whole, ammonium fluoride has a stronger modifying effect on polyester material than aqueous ammonia. __________ Translated from Khimicheskie Volokna, No. 1, pp. 17–21, January–February, 2007.     

Synthesis and characterization of water-soluble diazonium salts as contrast-enhancement materials

Water soluble aromatic diazonium double salts, p-diazodiphenylamine chloride zinc chloride (DZS-1) and p-diazoanisol chloride zinc chloride (DZS-2), have been evaluated as photobleachable dyes for contrast enhancement lithography. After testing the bleaching characteristics, aqueous solutions of DZS-1 and poly(vinyl alcohol) were used as a contrast enhancement material. Thermal stability, resist contrast, exposure parameters and other bleaching characteristics of the photobleachable membranes were investigated. A. commercial i-line photoresist was used to evaluate the contrast ratio of the DZS-1/PVA CEL layer. The contrast ratio obtained in this investigation is 1.67.     

Electrochemical characterisation of tetra- and octa-substituted oxo(phthalocyaninato)titanium(IV) complexes

The synthesis and electrochemical characterisation of the following oxotitanium tetra-substituted phthalocyanines are reported: 1,(4)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (5a); 1,(4)-{tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (5b); 2,(3)-(tetrabenzyloxyphthalocyaninato)titanium(IV) oxide (6a) and 2,(3)-{tetrakis[4-(benzyloxy)phenoxy]phthalocyaninato}titanium(IV) oxide (6b). The electrochemical characterisation of complexes octa-substituted with 4-(benzyloxy)phenoxy (9b), phenoxy (9c) and tert-butylphenoxy (9d) groups is also reported. The cyclic voltammograms of the complexes exhibit reversible couples I-III and couple IV is quasi-reversible for complexes 5a, 5b, 6a and 6b. The first two reductions are metal-based processes, confirmed by spectroelectrochemistry to be due to Ti^IVPc²⁻/Ti^IIIPc²⁻ and Ti^IIIPc²⁻/Ti^IIPc²⁻ redox processes and the last two reductions are ring-based processes due to Ti^IIPc²⁻/Ti^IIPc³⁻ and Ti^IIPc³⁻/Ti^IIPc⁴⁻. Chronocoulometry confirmed a one-electron transfer at each reduction step. The electrochemistry of the above complexes is also compared to the previously reported 5c, 5d, 6c and 6d.     

Carbonization of tetra-(octadecyl) titanate under very high pressures

Tetra-(octadecyl) titanate, a less reactive organic titanate, was carbonized under pressures up to 60 kb and the products were investigated by X-ray diffractometry and electron microscopy. The carbonization occurred on the high temperature side of a line connecting atmospheric-pressure/200°C and 60kb/480°C in the p-T chart. Due to explosions, however, flawless products could be recovered only above 30 kb and not far off the line. All the recovered carbonized products showed higher carbon yields and larger X-ray L_c-values than the equivalents obtained by pyrolyses under atmospheric pressure. The product at 30kb/420°C was composed of rutile and needle-shaped carbon fragments of various lengths, in which short graphitic lattice fringes were found to be stacked across the fragment axis. The products under pressures of 50 kb or higher contained rutile, β-titania and carbon fragments of numerous shapes, in which lattice fringes appeared rather irregular as compared with those in the 30 kb/420°C product.     

Studies of arenediazonium salts as a new class of electropolymerization initiator

Electropolymerization holds great potential as a novel process for applying surface coatings onto a variety of substrates. Cathodic electropolymerization has been conducted successfully on metal substrates using initiation systems, such as sulfuric acid and potassium persulfate. However, each of these initiation systems has its own deficiency. This provided the motivation for investigating arenediazonium salts as a new class of cathodic electropolymerization initiators. Our studies found that arenediazonium salts can be easily reduced at reduction potentials lower than that of water to generate initiating free radicals. The reduction efficiency is very high. A copolymer of methyl acrylate and acrylonitrile has been polymerized onto steel surfaces using one of these salts, 4-methyl benzenediazonium tetrafluoroborate, as initiator. Cyclic voltammetry and reflection absorption infrared spectroscopy (RAIRS) studies suggest a strong interaction exists between the initiator and the substrate, which can potentially enhance coating adhesion. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2265–2272, 1999     

四(对-磺酸钠苯基)卟啉的提纯

改进了四（对－磺酸钠苯基）卟啉（TPPS4）的合成,特别是提纯方法。以四苯基卟啉为原料,经氢横酸或浓硫酸处理合成了TPPS4,详细介绍了后处理过程。     

聚亚苯基乙烯衍生物作为电致发光材料的研究进展

含有大共轭体系的聚亚苯基乙烯衍生物具有柔性好、驱动电压低和能带结构可调性等优点,一直是聚合物有机电致发光材料的研究重点。聚亚苯基乙烯衍生物的结构具有多重性,可以通过不同的合成方法获得,材料的设计较为便利。本文主要综述了最近几年来PPV衍生物电致发光材料的研究进展,并对其发展方向及应用前景进行评述。     

Studies of pyrrole black electrodes as possible battery positive electrodes

It is shown that a polypyrrole, pyrrole black, may be formed anodically in several aqueous acids. The polypyrrole film shows a redox couple at less positive potentials than that required to form the film and the charge associated with these reduction and oxidation processes together with their stability to cycling varies with the anion in solution and the potential where the polypyrrole is formed; over-oxidation of the film caused by taking its potential too positive has a particularly disadvantageous affect. In the acids HBr and HI, the polypyrrole films can act as a storage medium for Br₂ or I₂ so that they may be used as a substrate for a X₂/X^– electrode. Such electrodes may be charge/discharge cycled and the pyrrole/Br₂ electrode shows promise as a battery positive electrode.     

Polypyrrole as possible electrode materials for the aqueous-based rechargeable zinc batteries

Polypyrrole (PPy) thin film electrode was galvanostatically synthesized and characterized in 0.1 M HCl on graphite electrode as cathode materials for the aqueous-based rechargeable zinc batteries. The charge/discharge characteristics of PPy and zinc electrode in 0.1 M ammonium chloride and in the 0.1 M ammonium chloride with addition of 0.1 M sodium citrate were investigated. Electrochemical characteristic of possible Zn|PPy cell in chloride/citrate containing electrolyte was discussed and simulated.     

Poly(ethylene glycol)-poly(epsilon-caprolactone) block oligomers as injectable materials

A family of segmented low MW poly(ethylene glycol)-poly(epsilon-caprolactone) (PEG-PCL) oligomers was synthesized by reacting PCL-based macrodiisocyanates and diblocks comprising MPEG and PCL short segments. The oligomers have the following general structure: MPEG350-(CL)_n-HDI-PCL530-HDI-(CL)_n-MPEG350. The composition of the oligomers and their molecular weight was determined by ¹H and ¹³C-NMR, FT-IR and GPC. Depending on the length of the (CL)_n block, soft waxes to hard solids were produced. The isothermal crystallization process was performed at various temperatures and investigated by DSC, FT-IR and WAXS, while the mechanical behavior was determined using a compression test. All the oligomers investigated were able to crystallize at low temperatures (4 and 25 °C), while at body temperature, only oligomers comprising longer (CL)_n blocks (n=5 and above), were able to crystallize.     

Studies on Me/Al-layered double hydroxides (Me = Ni and Co) as electrode materials for electrochemical capacitors

Me/Al-layered double hydroxides (Me=Ni and Co) prepared by the chemical co-precipitation method have been shown to be outstanding novel materials for electrochemical capacitors. The crystalline structure and the electrochemical properties of the electrodes have been studied by considering the effect of the mole ratio of nickel/cobalt. X-ray diffraction analysis shows that the materials belong to hexagonal system with layered structure. Cyclic voltammetric measurements indicate that Me/Al-layered double hydroxides with the Ni/Co mole ratio of 4:6 exhibit excellent capacitive properties within the potential range of 0.0-0.6 V versus Hg/HgO in 6 mol/L KOH electrolyte. Charge/discharge behaviors have been observed with the highest specific capacitance values of 960 F/g at the current density of 400 mA/g. Impedance studies show that the enhanced electrical properties and high frequency response are attributed to the presence of Co oxides.     

Pd(0)-catalyzed Heck reactions of isopropenyl acetate using bmim salts as pre-ligands

In the present paper, simple homogeneous catalytic protocols are presented for the production of methylketones under palladium catalysis from isopropenyl acetate and aryl or benzyl halides. Several reaction conditions were investigated and, although the use of Pd(OAc)₂/K₂CO₃/PPh₃ in ethanol gave the desired products in good yields, the use of bmim salts, to substitute PPh₃, as precursors of NHC ligands proved equally effective.     

Tris(acrylato)uranylates as a scaffold for NLO materials

Novel uranyl acrylate complexes with general formula R[UO₂(CH₂CHCOO)₃] (RK⁺, NH₄⁺, Rb⁺, or Cs⁺) were synthesized and characterized by X-ray diffraction, IR spectroscopy and second harmonic generation (SHG) measurements. All four compounds are isostructural and crystallize in the non-centrosymmetric P2₁3 space group. Acrylate anions act as bidentate chelating ligands forming [UO₂(CH₂CHCOO)₃]⁻ complexes which are connected through electrostatic interactions with counter ions. SHG measurements revealed the inverted correlation between the Q = I_2ω/I_2ω SiO₂ values and the radii of counter ions.     

The synthesis and electrochemical properties of a new tetra-(crown-ether-thiafulvalene)-annulated phthalocyanine derivative

A novel, metal-free, crown-ether-tetrathiafulvalene annulated phthalocyanine was synthesized by tetramerization of the corresponding phthalonitrile derivative; both compounds were characterized by elemental analysis, IR, UV–vis, DPV or CV and MS spectra. The crystal structure of the precursor was determined by X-ray crystallography. The charge transfer absorption bands of the two compounds lay ～400 nm after addition of 7,7,8,8-tetracyanoquinodimethane. Electrochemical studies revealed that both compounds displayed good complexation selectivity for Na⁺ ion with large positive redox shifts, indicating that they may be a new redox-active sensor.     

Electrooxidation and dischargeability of transition-metal borides as possible anodic materials in neutral aqueous electrolytes

A number of transition-metal borides were studied as anodic materials for neutral aqueous batteries. These borides are shown to have considerably high electrochemical activities in neutral electrolytes. The discharge capacities for TiB₂ reach 1,350 mAh g⁻¹ at a constant current density of 50 mA g⁻¹, exceeding those for all the metal electrodes reported so far. Amorphous CoB_x can deliver a discharge capacity of >650 mAh g⁻¹, and even simply ball-milled FeB_x can also give a discharge capacity of >200 mAh g⁻¹. These results suggest the possible use of boride compounds as a large family of new anodic materials for constructing neutral aqueous batteries with high electrochemical capacity and rate capability.     

Functional poly(p-phenylene)s as targeting and drug carrier materials

Polymers have a substantial attention in drug delivery systems owing to the diverse intrinsic advantages. It is important to carry the drug to the target site and release to exert its effects. Herein, poly(p-phenylene)s with amino and poly(ethylene glycol) substituents (PPP-NH₂-g-PEG) were used as a carrier for doxorubicin (DOX), an anticancer drug, and haloperidol, a sigma receptor targeting ligand. Both human cervix adenocarcinoma cell line (HeLa) and human keratinocyte cell line (HaCaT) having different Sigma receptor 1 (SigmaR1) expression levels were compared. HeLa was found to express twofold SigmaR1 compared to HaCaT cells. Cell imaging studies showed that, DOX cell uptake was higher in HeLa cells when targeted with haloperidol.     

Hydration of poly(acrylic acid) sodium salts

Summary Drying and water uptake of poly(acrylic acid) sodium salts with different degrees of neutralization were studied. The slowing down of drying speed in solid state was not due to Tg but due to the difficulty of the release of water molecule bound to two metal carboxylates or carboxyls. The equilibrium water uptake remained almost constant below 33 % neutralization, whereas it increased linearly with neutralization beyond 33 %. This was explained by the appearance of vacant sites in octet coordination.     

Hydration of poly(acrylic acid) potassium salts

Summary Drying and water uptake of poly(acrylic acid) potassium salts with different degrees of neutralization were studied. The slowing down of drying speed in solid state was not due to Tg but due to the difficulty of the release of water molecule bound to two metal carboxylates or carboxyls. The equilibrium water uptake decreased below 25% neutralization, whereas it increased linearly with neutralization beyond 25%. The bending in the plot of equilibrium water uptake was explained by the appearance of vacant sites in bodycentered cubic coordination. The initial decrease was attributable to the sum of the two opposite effect, that is, the decrease of free carboxyl groups and the increase in dielectric nature. The results were discussed in connection with those for sodium salts described in the preceding paper.